加温後のtsAF8細胞の細胞周期

Thermotolerance in tsAF8 cells develops during incubation at 34℃ after heating at 45℃, while it is suppressed by the following incubation at a non-permissive temperature of 39.7℃ after the same heating. The incubation temperature after heating may affect the cell cycle and consequently thermotolerance. In the present study, a relationship between the thermotolerance and the cell cycle of tsAF8 was investigated. The cell cycle fractions and DNA synthesis were measured by flow cytometry using double staining with propidium iodide and bromodeoxyuridine. When the tsAF8 cells were heated at 45℃ for 20 min, and thereafter incubated at 34℃, bromodeoxyuridine uptake in the S phase cells (DNA synthesis) was recovered to 65.1% 6 h after the heating, and the cells showed gradual accumulation in the G(2)/M phase. When the cells were incubated at 39.7℃ after heating at 45℃ for 20 min, then showed inhibition of thermotolerance development, the DNA synthesis was recovered to 15.1% temporarily 6 h after the heating, but it became 0% after 12 h, and the cells did not remarkably accumulate in any phases of the cell cycle. This inhibition of DNA synthesis at 39.7℃ was considered to be the result of cell survival decreasing by a step-down heating. However, the relationship between the thermotolerance and the cell cycle was not found out in tsAF8 cells, because the cells did not accumulate in any phases of the cell cycle under the inhibitory condition of thermotolerance.tsAF8細胞は45℃の加温後34℃で培養すると温熱耐性が速やかに発現するが,加温後,制限温度である39.7℃で培養すると温熱耐性の発現が抑制される｡加温後の培養温度が細胞周期に影響し,その結果として温熱耐性発現に影響を与えている可能性があることから,今回,Propidium Iodide(PI)とbromodeoxyuridine(BrdU)でtsAF8細胞を二重染色し,フローサイトメトリーによって温熱耐性と細胞周期の関係の有無について調べた｡tsAF8細胞を45℃20分の加温後34℃で培養すると,6時間後にはG(1)期の細胞が減少し,12時間後にはG(2)/M期への蓄積が見られた｡しかし,加温後39.7℃で培養した場合には細胞周期の進行がほとんど見られなかった｡BrdU の取込みは,加温せずに39.7℃で培養した場合には活発に行われ,また,45℃20分加温後34℃で培養した場合には,6時間後にはBrdUの取り込みは65.1%まで回復した｡しかし,温熱耐性発現の抑制が観察される45℃20分加温後39.7℃で培養した場合には,BrdUの取込み量は6時間後に一時的に15.1%に回復するが,12時間後には取込み量はゼロとなった｡BrdUの取り込みが阻害されたのはstep-down heatingの現象による細胞生存率の減少が原因だと考えられたが,温熱耐性発現の抑制が観察される条件下では細胞周期の特定の時期への集積がなかったことから,温熱耐性と細胞周期との関係はtsAF8細胞においては見い出されなかった

Rationalization of measures to protect the working environment in radiation controlled areas from the perspective of the relationship between surface and airborne contamination

放射線管理区域において業務従事者の放射線防護が正確に実施されていることを確認するために放射性同位元素の環境測定が行われている。しかし，実際の測定においては，濃度が低いなど実測困難な場合が多いこと，多くの人手と経費を要していることから，より合理的な測定の実施ができないかということについての検討が期待されている。このため本総説では，まず大学などの放射線管理区域における作業環境測定方法の現状についてまとめた。次に，放射線管理区域の床，作業台などにおける放射性同位元素の表面汚染と空気汚染に着目し，汚染粒子の移行など表面汚染と空気汚染の関係機構について，また，スミア法や直接測定法などの各種表面汚染測定法の汚染採取効率などを指標とした特性とこれら測定法の改良の試みについてまとめた。さらに，実際の作業場所において，作業内容，換気，表面材料などが表面汚染と空気汚染の関係に及ぼす影響について，その検討例を紹介した。得られた知見をまとめるとともに，測定箇所・測定頻度の適性化やそれぞれの測定箇所に適した測定法の選定など作業環境測定の一層の合理化に向けて，今後どのような検討が必要なのかについて提案した。In radiation controlled areas, measures have been taken to assess the radiation dose to workers, but these efforts are limited due to high labor and cost factors in extremely low dose radiation controlled areas. And so they have been expected to be rationalized. Therefore, we first reviewed the present conditions of these working environment measurement and elucidated the relationship between surface and airborne contamination in radiation controlled areas. Second, we reviewed the qualities of several surface contamination measurements such as smear test and possibilities for their improvement. As a result, we developed some future programs for rationalization of the working environment measurements, for example, an algorithm for selecting the proper surface contamination measurement for each measurement area based on the conditions specific to that area

Study of hadron interactions in a lead-emulsion target

Topological and kinematical characteristics of hadron interactions have been studied using a lead-emulsion target exposed to 2, 4 and 10 GeV/c hadron beams. A total length of 60 m $\pi^-$ tracks was followed using a high speed automated emulsion scanning system. A total of 318 hadron interaction vertices and their secondary charged particle tracks were reconstructed. Measurement results of interaction lengths, charged particle multiplicity, emission angles and momenta of secondary charged particles are compared with a Monte Carlo simulation and appear to be consistent. Nuclear fragments emitted from interaction vertices were also detected by a newly developed emulsion scanning system with wide-angle acceptance. Their emission angle distributions are in good agreement with the simulated distributions. Probabilities of an event being associated with at least one fragment track are found to be greater than 50% for beam momentum $P > 4$ GeV/c and are well reproduced by the simulation. These experimental results validate estimation of the background due to hadron interactions in the sample of $\tau$ decay candidates in the OPERA $\nu_{\mu} \to \nu_{\tau}$ oscillation experiment.Comment: 14 pages, 11 figure

現像温度および時間のマンモフイルム特性に与える影響

The influence for developing temperature and processing time within film processing conditions was investigated using four mammographic films, Konica New CM, Fuji UM-MA HC, Kodak Min-R M and Kodak EB/RA (for rapid system). And Fuji UR-2, a double-emulsion film, was used as a control. Those sensitometric strips exposed by a sensitometer were processed in the different combinations of developing temperatures ranging from 28 to 36℃, processing times from 45 to 210 sec. Average gradient, relative speed and base plus fog obtained from the measured film characteristic curves were evaluated for the different developing temperatures and times. Fuji UR-2 was scarcely affected and mammographic films were greatly affected in the different combinations without an increase in base plus fog except EB/RA. In New CM, UM-MA HC and Min-R M, the average gradients and the relative speeds increased as the developing temperature was higher and the developing time was longer, but the increases were limit on the combination of 36℃ and 210 sec in New CM and UM-MA HC. In EB/RA, the average gradients were almost constant and the relative speeds increased slightly like the double-emulsion film. These results suggested that it would be possible to contribute to dose reduction and advancement of contrast in New CM, UM-MA HC and Min-R M by changing these processing parameters.フィルム処理条件において,現像温度と処理時間に対する影響を4種類のマンモグラフィ用フィルムKonica New CM, Fuji UM-MA HC,Kodak Min-R M,迅速処理用Kodak EB/RAについて調べた｡そして,比較基準用として両面乳剤フィルムFuji UR-2を用いた｡感光計で露光したフィルムを現像温度28～36℃,処理時間45～210秒で処理した｡特性曲線から得られたフィルム特性（平均階調度,相対感度,カブリ濃度）を異なる現像温度,現像時間に対して評価した｡UR-2はほとんど影響を受けず,マンモグラフィ用フィルムは,カブリ濃度が上昇することなく,現像条件の影響を大きく受けた。New CM, UM-MA HC,Min-R Mは現像温度の上昇,処理時間の延長に伴い,平均階調度と相対感度は増加した｡しかし,New CM, UM-MA HCの36℃,210秒で増加は限度に達した｡EB/RAの平均階調度は一定で,相対感度は両面乳剤フイルムと同 様にわずかな増加であった｡これらの結果は,New CM, UM-MA HC, Min-R Mにおいて,処理条件を変化させることにより,被曝低減,コントラスト向上に貢献できる可能性を示唆していた

Approach on the simple and easy method for measurement of airborne radioactive iodine((125)I)

放射性ヨウ素（(123)I，(125)I，(131)I）は飛散しやすいなどの特性があり，他の放射性核種に比べ慎重な取扱いが求められている。また，この核種の空気中濃度限度は非常に低く，濃度測定には大量の空気を吸引しなければならず，そのための装置も大掛かりとなる。このため，本研究では，活性炭ろ紙をホルダにセットし，これを注射器に取り付けた簡易な装置を考案・試作し，空気中の放射性ヨウ素濃度を簡便に測る方法について実験・検討した。その結果，まず放射性ヨウ素にNa(125)Iを用いた場合の捕集効率は44.5％であることが分かった。次に，50mℓ注射器を用いて1ℓの空気を吸引・ろ過し，Nal（Tl）ウェルタイプシンチレーションカウンタで30分間放射能を測定した場合，本装置では空気中濃度限度の2.12倍の濃度の(125)Iが測定可能であり，気体状ヨウ素の漏れを防いで捕集効率を94.3％以上に上げることができれば，空気中濃度限度まで測定可能であることが示された。このため，本法は簡便かつ安価に異常を検知する測定方法として利用できるのではないかと考えられた。Radioactive iodines (iodine-123, -125, -131) are used as the marker in vitro test, nuclear medicine and so on. It is necessary to handle them carefully, because radioactive iodines scatter easily. As air concentration limits of radioisotopes are very low levels, we should prepare the measurement technique using a large-volumed aspirator and large-scaled equipments. In this study, we examined the simple and easy method for the measurement of concentration of airborne radioactive iodines. We designed and manufactured the simple set of holder and charcoal filter connected to hypodermic syringe. The collecting efficiency of airborne iodine-125 by this system was 44.5%. In the case of that a liter of the air was filtered by this system connected to 50 mℓ syringe and counted the radioactivity for 30 minutes by the NaI(Tl) well-type scintillation counter, It is indicated that iodine-125 of air concentration limit can be measured

A Study of Reconstruction of Magnetic Resonance Image

磁気共鳴は医学におけるイメージングにおいて重要なモダリティーであり,高度な数学的手法が画像の再構成に取り入れられている｡画像再構成の数学的手法および画像再構成にいたるまでの数学的な過程を理解するこは,MRIを学ぶものにとって非常に重要であるが,成書において明確な説明はなされていない｡ここでは,MR画像の再構成法を,複素関数と複素フ-リェ係数を用いて導いたので報告する｡Magnetic resonance is an important modality for medical imaging, and advanced mathematical techniques are introduced into the reconstruction of images. Clearly understandable explanations of the reconstruction of the MR image and of the mathematical derivation process have not been presented in the texts. Reconstruction of MR image is presented using the complex function and its relevant Fourier coefficients

The influence of air attenuation in characteristic curve for mammographic screen-film system

マンモグラフィ専用装置を使用して，距離法で低エネルギー領域のX線におけるマンモグラフィ用増感紙／フィルムシステムの特性曲線を得るためには，空気滅弱の影響を考慮する必要がある。その影響について，実効エネルギーから空気減弱分を補正，照射線量測定による補正，Bednarek法を応用した新距離法の3種類の方法を使って検討した。さらに，一般撮影装置でも，マンモ用システムに対して距離法で特性曲線を作成し，エネルギ ーの変化による影響についても検討した。その結果，3方法の特性曲線およびグラディエント曲線は，新距離法が高濃度域でわずかにずれるもののほぼ一致した。新距離法に対する平均階調度，最大階調度の最大誤差は，2.7％，0.2％であり，一般撮影用装置の距離法と3方法との間では，一般撮影用装置の距離法に対して最大誤差は2.7％，1.5％であった。以上のことから，エネルギーの変化による特性曲線への影響はほとんどなく，低エネルギー領域での特性曲線は空気特配の補正を行うことのみで得られると考えられる。It is necessary to take air attenuation into account when we use inverse square sensitometry to obtain characteristic curve for the mammographic screen-film system at low x-ray energies as used with the dedicated unit. Three kinds of the inverse square sensitometry approach of correcting by air attenuation obtained from effective energy, of correcting by exposure dosimetry and of using modified the technique of Bednarek were employed to investigated the influence of x-ray energy in the characteristic curves for the mammographic screen-film system. In addition, the inverse square sensitometry with the general radiographic unit was employed and the influence of x-ray high energy in the characteristic curves was also investigated for the same screeri-film system. Though characteristic curves and gradient curves of the new inverse square sensitometry were a little lower than the others in high-density region, the curves with three kinds of methods almost coincided. Maximum relative errors of average gradient and maximum gradient for modified the technique of Bednarek were found to be 2.7% and 0.2% among the others respectively. Moreover, maximum relative errors of gradient and maximum gradient for the inverse square sensitometry with the general radiographic unit were 2.7% and 1.5% among three kinds of methods with the dedicated unit respectively. It was considered that the characteristic curves for the mammographic screen-film　system were little influenced by x-ray energy and could be obtained only by correcting　air attenuation from above results

Views concerning nursing and nursing course of senior high school guidance teachers

1993年に岡山県で行った先の研究で,高校生の看護課程の選択にあたって,進路指導を行っている教師の役割が大きい事を報告した｡今回は3年経った1996年に,同じ郵送調査を岡山県および周辺10県の普通科高校617校より無作為に選んだ127校において実施した｡64校より得られた回答を要約すると以下の通りであった｡1.教師が挙げた看護婦不足の理由はまず｢勤務時間が厳しい(85.9%)｣,｢仕事の内容が厳しい(53.1%)｣といった仕事のきつさで,次いで｢仕事の割には社会的評価が低い(32.8%)｣であった｡2.教師が学生に肯定的イメージとして看護課程を勧める理由は,｢まず専門職であること(73.4%)｣,次いで｢人に貢献できる喜び(53.1%)｣であった｡これらの結果は前回の結果と比較して統計的な有意差は認めなかった｡3.近年進められている3年制看護課程(準学士課程)から4年制課程(学士課程)への移行に関して,教師はこれらは学生の関心を呼ぶとし(79.8%),看護課程へ進学する者は増加するであろうとしている(57.8%)｡またこれまでよりこの課程への進学を教師は勧め易くなるとしている(56.3%)。これらの率は前回の結果と比較すると統計的に有意に高かった。A previous study in Okayama prefecture in 1993 indicated the importance of high school teachers' influential rule on student's choice of nursing course. The same questionnaire survey was sent out by mail in 1996 to guidance teachers of 127 general high schools randomly selected from 617 schools in 10 prefectures, in and around Okayama. Data obtained from 64 teachers were analyzed and the results were as follows; 1. They suggested that shortage of nursing manpower was due to the harsh working conditions such as long and irregular hours (85.9%) and hard work (53.1 %), and also the low social esteem of nurse (32.8%). 2. The aspect of nursing noted by teachers were job specialty (73.4%) and devotion to people (53.l%). There were no statistical difference between these results and those of the previous study. 3. The teachers answered that the new four-year nuersing course (baccalaureate) currently being promoted from over the the present three-year course (associate degree) would be an incentive to students (79.8%) and might increase the number of students choosing to study nursing (57.8%). And they also noted that they would more readily recommend this course to students than before. These rates were significantly increased compared to the results of the previous report

Measurement of sampling time in MRI and reconstruction of MR image

MRIにおいてk-spaceを構築するためにはエコー信号をサンプリング時間に従って採取する必要がある.このサンプリング時間を測定するために,FOV(field of view)の左半分にファントムを置くことにより階段関数となるスピン分布を生成した｡得られたエコー信号を,階段関数をフ-リェ変換したときに得られるフ-リェ係数と比較することによりサンプリング時間を求めた｡得られたサンプリング時間を用いて,MRI MULTI-TEST PHANTOMをMRI装置でスキャンすることにより得られたエコー信号をサンプリングしk-spaceを構築した。このk-spaceをフ-リェ逆変換することによりMRI MULTI-TEST PHANTOMの画像を再構成することができた。Regarding the construction of k-space in MRI, it is necessary to extract the required data from the echo signals with the rate of sampling time. In order to measure the sampling time, a rectangular phantom was placed on the left side of the FOV in the body coil of an MRI equipment, and got analog signals in the sequence of spin echo. The sampling time was determined by comparing the measured signals with the Fourier coefficients obtained by transforming the step function which was similar to the profile of the FOV. The MRI MULTI-TEST PHANTOM was scanned, and the k-space was constructed with the extracted data from the echo signals with the rate of the determined sampling time. The MRI images of the MULTI-TEST PHANTOM were reconstructed by inverse-transforming the obtained k-space

Senior high school students' recognition and interest in allied medical education of college

1996年7～9月にかけて,岡山県周辺の10県下高校普通科3年在学中の学生に志望進路,志望分野とともに大学,短期大学における医療技術教育への認識と関心についてアンケート調査を行った｡サンプリングによって依頼した127校のうち回答が得られたのは52校(回収率40.9%)で,得られた回答数は合計1,998人(男子891人,女子1,077人,不明30人)であった｡これらの分析から,これらの地域では進学志望者の率は高く,特に男子に著名で,男女ともに理系への志望が多いことを認めた｡医療技術系大学の認識は看護学科を除いて低く,関心も特に男子で低かった｡4年制大学の進学を志望する学生にとっては, 3年制の多い医療技術系短期大学には関心が寄せがたく, 4年制へ移行した場合には関心も志望も高まる事が認められた｡将来この分野を担う人材の確保には現在の医療短大の4年制化や医療技術職の待遇改善が重要である と結論づけた｡A survey was carried out by senior high school students in Okayama and nine surrounding prefectures from July through September, 1996. Data obtained from 1998 twelfth-grade students studying general courses at 52 schools were computed. Eighty four percent of the 891 male students and 54.2% of the 1,077 female students wished to go on to senior college. Sixtyseven percent of the male students wished to enter science college courses, while only 25.8% of female students did. The rate of students who knew about the course of allied medical science in senior or junior colleges was 63.8% for male students and 82.5% for female students. The nursing course was popular among both sexes, but other courses such as radiological technology, medical technology, physical therapy and occupational therapy were not well known, especially among male students. It was thought that students wishing to go on to the senior college were not interested in those areas which were usually taught in three year courses at junior colleges or special (vocational) schools. Accordingly, the data showed that their interests in the allied medical course would be increased by the shifting it to a four year course. To attract senior high school students who are both intelligent and talented in the medical and health field, the authors concluded that the further improvement of educational course for allied medicine, especially such as shifting to a four year course, and the bettering of position of comedical workers through it are needed