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Larval movement of the cigarette beetle, Lasioderma serricorne, in whole wheat flour
Get PDFThis study was conducted to clarify larval movement of the tobacco beetle, Lasioderma serricorne, in whole wheat flour. Thirty adults emerged within 4 days were released in mixed sex on the surface of 3 cm deep whole wheat flour in a PVC case. The case was made of pipe cut into 6 slices to a width of 1 cm in advance and each slice was named R1 to R6 from a bottom side. After adults were allowed to lay eggs for 7 days, they were removed. At the same time, 2 cm more flour was added on the surface of 3 cm flour. Newly hatched larvae could move from oviposition site (R3) to 2 cm upper side or 3 cm down side in the flour. Three weeks later, the number of larvae in each slice was counted. Larvae were observed at all slices and the most larvae were significantly observed in R5 (30.9±2.8%). This result indicates that many larvae move from the oviposition site to upper side, when more flour is deposited on the oviposition site.journal articl
Prevention of Chronic Rejection of Marginal Kidney Graft by Using a Hydrogen Gas-Containing Preservation Solution and Adequate Immunosuppression in a Miniature Pig Model
Get PDFIn clinical kidney transplantation, the marginal kidney donors are known to develop chronic allograft rejection more frequently than living kidney donors. In our previous study, we have reported that the hydrogen gas-containing organ preservation solution prevented the development of acute injuries in the kidney of the donor after cardiac death by using preclinical miniature pig model. In the present study, we verified the impact of hydrogen gas treatment in transplantation with the optimal immunosuppressive protocol based on human clinical setting by using the miniature pig model. Marginal kidney processed by hydrogen gas-containing preservation solution has been engrafted for long-term (longer than 100 days). A few cases showed chronic rejection reaction; however, most were found to be free of chronic rejection such as graft tissue fibrosis or renal vasculitis. We concluded that marginal kidney graft from donor after cardiac death is an acceptable model for chronic rejection and that if the transplantation is carried out using a strict immunosuppressive protocol, chronic rejection may be alleviated even with the marginal kidney.journal articl
Human placental hydrolysate promotes the long-term culture of hepatocyte-like cells derived from canine bone marrow
Get PDFLong-term culture of canine artificial hepatocytes has not been established. We hypothesized that human placental hydrolysate (hPH) may support the long-term culture of differentiated hepatocyte-like cells. Canine bone marrow cells were cultured using modified hepatocyte growth medium supplemented with hPH. Quantitative reverse transcription polymerase chain reaction (RT-PCR) and immunocytochemical analysis for albumin, qualitative RT-PCR for cytochrome P450 1A1 (CYP1A1), hepatocyte growth factor (HGF), Cytokeratin 7 (CK7), CD90, CD44, and CD34, and functional analyses of CYP450 activity and low-density lipoprotein (LDL) uptake were performed. Cultured hepatocyte-like cells were able to maintain hepatocyte characteristics, including morphology, albumin synthesis, CYP450 activity, and LDL uptake for 80 days. Thus, hPH may be a potential facilitator for the long-term culture of hepatocyte-like cells. Clinicopathologically, this culture protocol of artificial hepatocytes will contribute to liver function evaluation.journal articl
Efficient Lipid Bilayer Formation by Dipping Lipid-Loaded Microperforated Sheet in Aqueous Solution
Get PDFThis paper describes a method for a bilayer lipid membrane (BLM) formation using a perforated sheet along with an open chamber. Microscopic observation of the formed membrane showed a typical droplet interface bilayer. We proved that the formed membrane was a BLM based on electrical measurements of the membrane protein α-hemolysin, which produces nanopores in BLMs. Unlike the conventional approach for BLM formation based on the droplet contact method, this method provides aqueous surfaces with no organic solvent coating layer. Hence, this method is suitable for producing BLMs that facilitate the direct addition of chemicals into the aqueous phase.journal articl
Research on the function of dog tears in the formation of bonds between human and dog.
Get PDF麻布大学博士(獣医学)Dogs were the first animals to be domesticated. They have a long history of coexisting with humans. During that time, dogs have developed human-like communication skills, including the ability to empathize with humans. It is thought that empathy of pleasant emotions lies behind the symbiotic and bonding relationship between humans and dogs. Furthermore, if there were a bond similar to that between human parents and children, then it could be expected that separation would be a source of stress and reunions would be joyful. Interestingly, dogs are reported to be extremely happy to see their owners again, but there is only limited research on the behavioral physiology of this response. In this study, we focused on the contexts where dogs were reunited with their owners and investigated the behavioral physiological changes in the dog that occurs at that time.
In Chapter 2, we conducted the experiment where dogs are separated and reunited with their owners on a daily basis to check whether there are changes in the amount of tear secretion associated with the change in the dog’s behavior. Given that oxytocin levels increase in dogs in the contexts involving interactions between them and humans and that oxytocin increases tear secretion and activates the parasympathetic nervous system, we hypothesized that oxytocin is also involved in the production of emotional tears and measured the tear volume after administration of oxytocin eye drops. The results revealed that there was no increase in tear volume during reunions with strangers, but only during reunions with the dog’s owner. Furthermore, there was an increase in tear volume due to the administration of oxytocin eye drops. This finding suggests that dogs secrete oxytocin through contact with their owners when reunited with their owners. It is thought that this oxytocin acts on oxytocin receptor cells in the lacrimal glands, which increases tear volume, so we considered it necessary to measure the serum oxytocin levels.
In Chapter 3, we verified the efficacy of rabbit anti-oxytocin polyclonal antibodies newly created in this laboratory and the reliability of the measurements. The results showed high sensitivity and specificity against to oxytocin, and there were high degree of correlations in the dilution test and spike recovery test. We obtained equivalent measurement results compared with the standard measurement method, indicating the establishing a oxytocin ELISA methods using a newly generated oxytocin antibody. However, we did not obtain any correlation with oxytocin in blood, which has been problematic to date, compared with the conventional RIA technique. This may be due to unknown molecular characteristics of oxytocin, such as changes to the three-dimensional structure of oxytocin caused by the extraction method and after extraction because oxytocin in the blood adheres to binding proteins. Although efforts have been made so far, it was deemed difficult to ascertain the blood kinetics, so it was decided to measure changes in oxytocin secretion by dogs that were reunited with their owners (covered in the next chapter) using the conventional RIA technique.
In Chapter 4, we found that the amount of tear volume increased when dogs were reunited with their owners, as seen in Chapter 2. The volume was higher than when the dogs encountered a stranger. However, there was no increase in oxytocin in that experimental settings. The oxytocin reduces by half within 3 minutes after secretion, so we are awaiting future development of technology that would enable it to measure the levels of hormones like oxytocin in the blood within a short time. Further verification of the changes in oxytocin and tear volume is required, either through fluctuations of oxytocin levels in the central nervous system or detailed sampling of oxytocin in the blood.
In Chapter 5, we instilled artificial tears in dogs’ eyes, took photographs of the dogs’ faces, and examined the impression humans had when viewing the photographs of the dogs to investigate the social effect of dogs shedding tears, focusing on the effect on humans’ feelings. We conducted a Wilcoxson signed rank-sum test comparing two types of photographs, one taken before the instillation of artificial tears and the other taken after, both involving the same dog, to determine if human evaluation differed with the photographs. The results indicated that, of the experiments conducted with thirteen pairs of photographs, the impression was significantly positive due to the presence of tears in seven pairs and negative with only one pair, suggesting that the presence of tears improved the positive impression of dogs.
Dogs had increased tear volume when reunited with their owners after a period of separation. This suggests that dogs exhibit emotional tears and manifest those tears with positive emotion (when reunited with their owners). This is the first time the presence of emotional tears in animals has been demonstrated. Furthermore, dogs showed no increase in tear volume when reunited with a stranger, and there was a significant increase in tear volume only when they reunited with their owners after a period of separation. Thus, it was found that the increase in tear volume occurs when dogs experience dramatic emotional changes such as reuniting with their owners with whom they have a special relationship after a period of separation. Moreover, oxytocin is an important hormone for building special relationships, and as tear volume increased with the administration of oxytocin eye drops, this suggests that the tear volume might have increased due to the increase in oxytocin secretion in dogs when reunited with their owners after a period of separation. Unfortunately, in Chapter 4, we were unable to clarify the correlation between elevated serum oxytocin levels in dogs reunited with their owners after a period of separation and oxytocin and tear volume. This research needs to be conducted with a higher level of accuracy. It was also clarified that changes in eye appearance with the instillation of artificial tears had a positive impact on humans. Dogs shedding emotional tears need to be further investigated by studies such as ones that seek to confirm the presence of emotional tears in wolves, but this finding suggests that these tears may be a function dogs acquired through the process of coexisting with humans, as it worked to their advantage. Dogs have highly evolved communication skills with humans by using their eyes, so tears may also perform the function of triggering protective and caring behavior in the dog’s owners. It might be possible to further unravel the history of symbiosis between dogs and humans in the future by combining these findings with the development of behavioral genetic studies. It is also known that the original role of tears in rodents is like a pheromone, and tears also function like a pheromone in humans. Tears may also function as a pheromone in dogs, so it will be necessary to clarify the function of dog tears within the same species.イヌは最も早く家畜化された動物であり、ヒトとの共生の歴史が長い。その歴史の中でイヌはヒトに対する共感性を含め、卓越したコミュニケーション能力を身に付けてきた。ヒトとイヌの共生や絆の背景には、快情動の共感性の存在があると考えられる。またヒトの親子間で見られるような絆があるとすれば、分離がストレスになり、再会が喜びであると想像される。逸話的にはイヌは飼い主との再会で非常に喜ぶとされているが、その行動生理学的な研究は限られている。今回、我々は飼い主とイヌの再会場面に着目し、その時のイヌの変化を、行動生理学的に調べた。
2章ではイヌの情動の変化に付随して涙の分泌量が変化するのかを確認するために、日常的な飼い主との分離再会場面を用いて実験を行った。またイヌとヒトとの交流場面でイヌのオキシトシンも上昇すること (Odendaal et al. 2003, Handlin et al. 2011, Nagasawa et al. 2015)、オキシトシンが、涙液を増やす副交感神経系を賦活化させること（Norman et al. 2010, Romero et al. 2014） から、情動の涙にもオキシトシンが関与していると仮説を立て、オキシトシン点眼後の涙液量を測定した。その結果、涙液の増加は他人との再会では認められず、飼い主との再会時のみ認められた。さらにオキシトシンの点眼によって涙液量の増加が認められた。 このことは、飼い主との再開場面において、イヌが飼い主とのふれあいを介してオキシトシンを分泌し、そのオキシトシンが涙腺のオキシトシン受容体細胞に作用することで涙液量を増加させたと考え、オキシトシンの測定が必要と考えた。
脳内のオキシトシンの活性は測定することが困難なことから、脳下垂体から分泌されたオキシトシンを末梢にて計測することで、脳内オキシトシンの活性を捉える手法が一般的である。末梢では血中オキシトシンに加え、尿中、唾液中のオキシトシンが測定されるが、まだ安定した測定系は少ないのが現状である。
3章では本研究室で新たに作成したウサギ抗オキシトシンモノクローナル抗体の有用性とその測定の信頼性を検証した。その結果、高い感度と特異性、さらに添加回収試験でも高い相関性が見いだされ、また旧測定法との比較でもほぼ同等の測定結果が出るなど、新たなオキシトシン抗体の作成とそれを用いたオキシトシンELISA法を確立できた。一方、これまで困難と言われてきた血中のオキシトシンに関しては、従来のRIA法と比較し、相関が得られなかった。このことは、おそらく血中のオキシトシンが結合タンパク質に付着しており、抽出方法や抽出後におけるオキシトシンの立体構造の変化など、未だ明らかにされていないオキシトシンの分子特性によるものと思われる。新たに確立したELISA法では、血中動態を知ることが困難と判断し、次章の飼い主との再会場面におけるイヌのオキシトシン分泌変化に関しては、従来のRIA法によって、測定することとした。
4章では2章と同様に、イヌは飼い主との再会場面において涙液量が増加することがわかった。それは見知らぬ人と比較しても高かった。しかしながらその場面におけるオキシトシンの増加は認められなかった。オキシトシンの半減期は約3分といわれていることから、今後は、オキシトシンなどの血中ホルモンを、短い時間軸で計測できる技術の開発が待たれる。またオキシトシンと涙液量の変化に関しては、今後中枢でのオキシトシン変動あるいは、血中の詳細なサンプリングによる、さらなる検証が必要と考えられた。
5章では、イヌが涙を呈することによる、社会的な効果、特にヒトへの作用を調べるため、イヌに人工涙液を点眼して顔写真を撮影し、イヌの写真を見たヒトがどのような印象を持つかを調査した。同一犬で人工涙液点眼前と点眼後の2種の写真間において、Wilcoxson singed rankテストを実施し、写真間でヒトの評価が異なるかを検定した。その結果、13枚の写真のペアで実験を行ったうち、7ペアで涙によって印象が有意にポジティブとなり、1ペアでのみネガティブとなり、涙の存在によるイヌのポジティブな印象が上昇することが示唆された。
考察：飼い主との分離後の再会時において、イヌの涙液量の増加が認められた。このことは、イヌが情動性の涙、それも飼い主との再会という快情動場面での涙を呈することが示された。動物における情動性の涙の存在を示した最初の成果となった。また涙液の増加は他人との再会時には認められず、飼い主との分離後の再会時にのみ涙液量の有意な増加が見られた。涙液の増加はイヌと特別な関係性のある飼い主との分離後の再会のようにイヌの情動が激しく変化する場面において認められることが分かった。さらに、オキシトシンは飼い主とイヌを含む特別な関係を築く上で、重要なホルモンであると考えられているが、オキシトシンの点眼によって涙液量の増加が認められたことで、飼い主との分離後の再会によるイヌのオキシトシン分泌が上昇したことで、涙液量が増加した可能性が示された。一方、第4章では飼い主との再会場面におけるイヌのオキシトシン上昇、オキシトシンと涙液量の関係性は明らかにできなかった。この研究は、さらに精度を高めて実施する必要性がある。また、人工涙液による目の変化がヒトにポジティブな印象を与えることが明らかとなった。イヌが情動性の涙を呈することは、オオカミでの情動性の涙の存在の確認など追加の検討が必要であるものの、ヒトとの共生において有利に働き、その過程で獲得された機能である可能性が示された。視線を用いたヒトとのコミュニケーション能力を高度に進化させてきたイヌの涙にも飼い主の保護行動や養育行動を引き起こすような機能があるのかもしれない。
今後、行動遺伝学的研究の発展と組み合わせることで、さらにイヌとヒトの共生の歴史が紐解かれるかもしれない。また本来の涙の社会的役割はげっ歯類ではフェロモンであり、ヒトでもフェロモンとして機能していることが分かっている。イヌもフェロモンとしての機能を持っている可能性があり、今後イヌの涙がもつ同種間の機能の解明が必要であろう。doctoral thesi
Combination Therapy of Hypofractionated Radiotherapy and Surgical Resection for Canine Intranasal Tumors
Get PDFUntreated canine intranasal tumors have a poor prognosis. The median survival time of dogs with intranasal tumors when treated with hypofractionated radiotherapy alone does not typically exceed one year. In this retrospective study, we evaluated dogs treated with hypofractionated radiotherapy followed by surgical debulking. Among 18 dogs, four had stage I, one had stage II, five had stage III, and eight had stage IV tumors. Surgery was performed either immediately after the final radiation treatment or 1–2 months after radiotherapy. Following macroscopic tumor resection after surgery (p = 0.008), the timing of surgery ≥ one month postradiotherapy (p = 0.011) and the early tumor stage (I–III; p = 0.043) were potentially associated with a favorable progression-free survival. The median overall survival in the early stages was 26 months. Therefore, microscopic residual tumor resection should be considered one month after completion of hypofractionated radiotherapy for dogs with early-stage tumors.P(論文)原著論文application/pdfORIGINAL ARTICLEdepartmental bulletin pape
Study on the assessment method of dietary acrylamide exposure and Epidemiologic analyses of the association between dietary acrylamide intake and pancreatic cancer risk using large-scale cohort data
Get PDF麻布大学博士(学術）Acrylamide (AA) was classified as 'probably carcinogenic to humans' by the International Agency for Cancer Research. According to the report of an assessment conducted by the Food Safety Commission of Japan in 2016, the neoplastic risk related to acrylamide intake for Japanese could not be excluded because of the insufficient margin of exposure (MOE). Therefore, more epidemiologic studies on dietary acrylamide intake and cancer risk are warranted. We first conducted this study on the method of assessing acrylamide exposure and then performed epidemiologic analyses of the pancreatic cancer risk using large-scale cohort data. The summary is as follows:
1. Study on the assessment method of dietary acrylamide exposure
【Introduction】
Before the epidemiologic study of exposure and disease risk, studies on dietary acrylamide exposure assessments are needed. Methods such as dietary records (DRs) and food frequency questionnaires (FFQs) are used to assess dietary acrylamide exposure. However, because most of these surveys are conducted over a short period, it is unknown whether the estimated intake represents the actual long-term acrylamide exposure at the individual level. To grasp the habitual acrylamide intake at the individual level, it is necessary to understand the variation factors of intake and to consider their effects. Within-individual and between-individual variations in dietary intake are known as variation factors. However, no studies have evaluated these variation factors in dietary acrylamide intake.
FFQs are often widely used to study the association between acrylamide intake and disease. A previous Japanese cohort study suggested the validity of the FFQ; it has been reported that dietary acrylamide intake in the Japanese population is lower than that in the Western population. However, these surveys were conducted in 1995 and 1998, and almost no studies have been conducted recently.
This study aimed to identify variations in the estimated dietary acrylamide intake of the Japanese population and to validate the FFQs for the estimation of acrylamide intake.
1.1 Study on within-individual and between-individual variations in acrylamide intake using dietary records
【Methods】
The study included 240 participants aged 40–74 years living in five areas in Japan. Twelve-day DRs were collected between 2012 and 2013. Dietary acrylamide intake was estimated from an acrylamide content database. Within-individual and between-individual variations were calculated using the random-effects model.
Furthermore, using the calculated within-individual and between-individual variations, we estimated the number of days for a dietary survey required to evaluate individuals’ usual intake and rank individuals in a group. For foods that predict between-individual variations in acrylamide intake, multiple regression analysis using the stepwise method was performed, and the partial contribution rate and cumulative partial contribution rate were calculated for each food group.
【Results】
The ratio of within-individual variation to between-individual variation was 3.9, and within-individual variation was larger than between-individual variation. Days of DRs necessary for estimating the true intake within 10% and 20% were 255 days and 64 days, respectively. The number of days required to ensure an R-value of 0.8 for ranking individuals was seven days. Foods that contributed to the between-individual variations were in the following order: coffee/cocoa, potatoes, green tea, sweet potatoes, and biscuits/cookies. These top seven foods accounted for approximately 93% of the total variation.
【Discussion】
We demonstrated that estimating the habitual dietary acrylamide intake from DRs requires an extended data collection period due to the large within-individual variation in dietary acrylamide intake. We indicated that the number of days of dietary recording required to estimate individuals’ intragroup ranking with a certain degree of accuracy is approximately seven days. Therefore, when the variation ratio and/or within-individual variation is large, the estimation of acrylamide intake using short-term dietary surveys may lead to a misclassification of rankings and may not represent an individual’s habitual intake. For foods predicting between-individual variation, our results suggest that it is possible to rank the acrylamide intake according to several kinds of foods.
【Conclusion】
Estimating acrylamide intake using DRs requires an extended data collection period to evaluate individuals’ intragroup ranking and habitual intake.
1.2 Study on the validity of the Food Frequency Questionnaire (FFQ) in estimating dietary acrylamide intake
【Methods】
FFQs were administered twice between 2012 and 2013 at an interval of 1 year. Dietary acrylamide intake was estimated from an acrylamide content database. FFQ validity was assessed by Spearman’s correlation coefficients between the FFQ and DR estimations and by weighted kappa coefficients, which indicate the degree of agreement of the ranking between the DRs and FFQs.
【Results】
The mean ± standard deviation (SD) dietary acrylamide intake values were 0.17 μg/day in DRs and 0.16 μg/day in FFQs. The main food groups from the DRs that contributed to the acrylamide intake were coffee/cocoas (25%), green tea (12%), potatoes (7%), traditional dry confections (6%), and biscuits/cookies (5%). The value of the estimated acrylamide intake determined using the FFQ indicated that the energy-adjusted and deattenuated correlation coefficients were 0.39 for men and 0.33 for women. The weighted kappa coefficients were 0.83 for men and 0.81 for women.
【Discussion】
The mean intake in our study was half of that in Western populations and was similar to that of the previous Monte Carlo simulation studies of Japanese populations. Therefore, compared to the surveys in the 1990s, our results suggested that the acrylamide intake increased slightly, and the foods that contributed to the intake were almost the same, but the contribution proportion was different in some foods.
In this study, the validity of estimating acrylamide intake using the FFQ was similar to that in the previous study, and high kappa values were found. Therefore, the FFQ is suitable for ranking individual intragroup.
【Conclusion】
The high kappa-values between DR and FFQ suggest that FFQ is appropriate for individuals’ rank within a population in epidemiological studies.
2. Epidemiologic analyses of the association between dietary acrylamide intake and pancreatic cancer risk using large-scale cohort data
【Introduction】
Some acrylamide is metabolized to glycidamide by cytochrome P450 (CYP2E1). Glycidamide is known to cause genotoxicity by forming an adduct that binds to hemoglobin and DNA. Epidemiological studies have investigated the association between pancreatic cancer risk and dietary acrylamide intake.
A recent meta-analysis, including four studies conducted in Western countries, showed that dietary acrylamide intake was not associated with the risk of pancreatic cancer. However, the evidence for the risk of pancreatic cancer may be insufficient owing to the very small number of studies. Moreover, all previous studies were conducted in Western countries and did not examine the relationship between dietary acrylamide intake and the risk of pancreatic cancer among Asians. This study aimed to identify the association between dietary acrylamide intake and pancreatic cancer risk in the Japanese population.
【Methods】
The study included approximately 140,000 participants aged 40–69 years who lived in 10 public center areas between 1990 and 1993. The inclusion criterion for participants was respondents to the 5-year follow-up survey. The exclusion criteria were as follows: 1) ineligible participants (living in different targeting areas, late report of migration occurring before the starting point, non-Japanese nationality, incorrect birth date, duplicate registration, participants who had died, moved out of the study area, or were lost to follow-up before the starting point); 2) participants with a history of cancer identified using the questionnaire; and 3) participants with missing or extreme energy intake dates. The final analysis included approximately 90,000 participants.
The study design was prospective cohort study, and the participants were followed up from the starting point of the 5-year follow-up survey (1995 or 1998) until 2013 for pancreatic cancer incidence.
Acrylamide intake for each participant was estimated using the database. The Cox proportional hazards model was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for energy-adjusted acrylamide intake and pancreatic cancer risk by percentile. The lowest acrylamide intake group was used as a reference. Furthermore, we stratified the analyses based on variables that were pancreatic cancer risk factors, such as smoking status, coffee intake, green tea intake, alcohol consumption, and body mass index (BMI).
【Results】
After a mean follow-up of 15.2 years, a total of 576 pancreatic cancer cases were identified. The mean acrylamide intake (SD) was 6.92 ± 3.81 μg/d, corresponding to 0.13 ± 0.16 μg/kg body weight/day. The group with the highest acrylamide intake (Q4) was younger, had a higher proportion of current smokers, and a higher intake of coffee.
We found no association between dietary acrylamide intake and pancreatic cancer. In the multivariate-adjusted model, the HR of the highest quartile vs. the lowest was 0.83 (95% CI: 0.65–1.05) (P for trend = 0.07). There were also no significant associations on the stratified analyses by sex, smoking status, coffee intake, green tea intake, alcohol consumption, and BMI.
【Discussion】
In a large prospective cohort of Japanese patients, no association was found between pancreatic cancer risk and dietary acrylamide intake. Previous studies that assessed dietary acrylamide intake and cancer risk (such as breast cancer and digestive system cancer) in the Japanese population have consistently indicated a null association. A lower dietary acrylamide intake in the Japanese population compared to that in the Western population is considered a reason for the lack of association. In addition, our findings were consistent with those of previous studies. Therefore, there might not be a substantial difference in susceptibility to acrylamide intake between Asian and Western populations.
In stratified analyses by sex, smoking status, coffee consumption, green tea consumption, alcohol consumption, and BMI, no association was found between pancreatic cancer risk and dietary acrylamide intake. However, multiple factors related to diet and lifestyle may affect acrylamide metabolism. Therefore, further studies are warranted to explore the factors that affect acrylamide metabolism using biomarkers.
【Conclusion】
Dietary acrylamide intake was not associated with the pancreatic cancer risk in Japanese individuals.
【Summary】
Acrylamide is expected to be quantitatively evaluated in terms of its potential carcinogenic risk to humans. However, this study identified that the individual intake (absolute value) estimation requires long-term dietary survey records owing to large within-individual variations. These results may serve as primary data for exposure assessment methods in the health impact assessment of acrylamide in food safety policies.
In addition, epidemiological analysis of acrylamide intake and risk of pancreatic cancer showed no association, but there have been few studies worldwide so far, and since this is the first study in Asia, it has great significance from the viewpoint of public health.アクリルアミドは国際がん研究機関の発がん性分類で、「ヒトに対しておそらく発がん性がある物質」とされる。2016年の食品安全委員会による健康影響評価では、「日本人における発がん性については懸念がないとは言えない」と評価され、アクリルアミド摂取とがん罹患に関する研究が求められている。本研究では、まずアクリルアミド摂取量の曝露評価方法に関する基礎的検討を行い、次に大規模コホートデータを用いたすい臓がんの発がんリスクに関する疫学的解析を行った。
\n1 食事由来アクリルアミド摂取量の曝露評価方法に関する基礎的検討
【背景】
曝露と疾病リスクとの疫学的検討に先がけ、曝露評価方法の基礎的検討が必要である。アクリルアミド摂取量の曝露評価方法には、食事記録法（dietary record, DR）、食物摂取頻度調査法（food frequency questionnaire, FFQ）などが用いられている。しかしながら、既存調査の多くは短期間の調査で、推定された摂取量が個人の習慣的な摂取量を反映するか不明である。習慣的な摂取量を個人レベルで把握するためには、摂取量の変動要因を理解し、その影響を考慮する必要がある。摂取量の変動要因として個人内変動と個人間変動があるが、アクリルアミド摂取量の個人内・個人間変動を検討した研究はこれまでに行われていない。
またFFQは、アクリルアミド摂取量と疾病との関連を検討する際に使用されることが多い。これまでに日本人を対象としたコホート研究では、FFQの妥当性が示唆されるとともに、日本人のアクリルアミド摂取量が欧米の集団と比較して少ないことが報告されている。しかしながら、それらは1990年代に実施した調査であり、より近年の研究は少ないのが現状である。
そこで本研究では、DRを用いたアクリルアミド摂取量の個人内・個人間変動の検討およびアクリルアミド摂取量推定におけるFFQの妥当性を検討した。
\n1.1 食事記録法（DR）を用いたアクリルアミド摂取量の個人内・個人間変動の検討
【方法】
全国5地域に在住の男女 240名(40～74歳)を対象とした。2012～13年に実施した12日間のDR（3日間×4季節）をもとにアクリルアミド含有量のデータベースを用いて、個人のアクリルアミド摂取量を推定した。DRから推定されたアクリルアミド摂取量を用い、混合効果モデルによって個人内・個人間変動を算出した。さらに個人内・個人間変動を用いて、個人の習慣的な摂取量の推定および集団における個人の順位付けに必要な食事調査日数を推計した。また、アクリルアミド摂取量の個人間変動を予測する食品については、ステップワイズ法を用いた重回帰分析を実施し、食品グループごとに偏寄与率、累積偏寄与率を算出した。
【結果】
個人間変動に対する個人内変動の分散比は3.9であった。個人の習慣的な摂取量を推定するために必要な食事調査日数として、個人の真値の95%信頼区間の10％および20％の誤差範囲に入るためには、255日および64日と推定された。また集団における個人の順位付けに必要な食事調査日数は、観測値と真の値の間の相関係数を0.8と想定した場合、7日必要であると推計された。また、個人間変動を予測する主な食品は、コーヒー、じゃがいも、緑茶類などで、それらを含む上位7食品で個人間変動の約90%以上をカバーした。
\n【考察】
個人の習慣的なアクリルアミド摂取量を推定するには、エネルギーなどの主要な栄養素と比較して、長期間の日数を要することが明らかになった。また集団内において、ある程度の精度で個人を順位付けするには1週間程の調査日数が必要であることが判明した。したがって、食事由来のアクリルアミド推定曝露量は個人内変動が大きいため、曝露評価を行う際に短期間の食事調査方法を用いると、個人内変動に起因する測定誤差が大きくなることが示唆された。個人間変動を予測する食品については、限られた食品数で個人間変動を予測できることが示唆された。
【結論】
DRを用いたアクリルアミド曝露評価において、集団内の順位付けおよび個人の習慣的な摂取量を推定するためには、長期間の食事調査日数を要することが明らかになった。
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1.2 食事由来のアクリルアミド摂取量の推定における食物摂取頻度調査票（FFQ）の妥当性の検討
【方法】
2012～13年に1年間隔で実施した2回のFFQを用いて、個人ごとのアクリルアミド摂取量を推定した。DRを比較基準としたSpearmanの順位相関係数、DRとFFQ間の順位付けの一致度を示すκ係数（一致度100%を１とする）を算出し、FFQの精度を評価した。
【結果】
体重kgあたりのアクリルアミドの平均摂取量は、DRで0.17μg/day、FFQで0.16μg/dayと推定された。アクリルアミド摂取量に寄与する主な食品（寄与割合%）は、コーヒー・ココア（25%）、緑茶（12%）、じゃがいも（7%）、和干菓子類（6%）、ビスケット（5%）であった。またFFQの精度は、エネルギーおよび日間変動を調整した相関係数は男性で0.39、女性で0.33であった。κ係数は、男性で0.83、女性で0.81であった。
【考察】
本研究の平均アクリルアミド摂取量は、欧米の報告値の半分以下で、2012年の食品安全委員会のモンテカルロシミュレーションによる推定値に近似していた。本研究の推定値は、1990年代の研究と比較してやや多く、コーヒーや菓子類の摂取量が多くなったことに起因していると考えられた。
FFQの精度は、DRとFFQ間の相関係数が類似の妥当性研究と近似していることや、DRとFFQ間で高い一致度が確認されたことから、集団内における個人の順位付けにおいて、ある程度の正確性があると考えられた。
【結論】
DRとFFQ間の高いκ係数より、疫学研究において、集団内の個人の順位付けにFFQの使用が可能であると考えられた。
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２ 大規模コホートデータを用いた食事由来アクリルアミド摂取量と
すい臓がんのリスクに関する疫学的解析
【背景】
アクリルアミドの一部は、シトクロムP450（CYP2E1）によってグリシダミドに代謝される。グリシダミドは、ヘモグロビンやDNAと付加体を形成し、遺伝毒性を有すると考えられている。現在、膵臓がんのリスクと食事中のアクリルアミド摂取量との関連について検討が行われている。欧米の4報の疫学研究を統合したメタアナリシス（複数の疫学研究を統合し、解析する研究方法）では、膵臓がんの罹患リスクは認められていない。しかしながら、研究数が少なくエビデンスの根拠として乏しい。さらに、既存研究はすべて欧米で実施され、アジアにおいて検討されていない。そこで本研究では、食事に由来するアクリルアミド摂取量とすい臓がん罹患の関連を検討した。
\n【方法】
1990～1993年に全国10地域に居住していた40～69歳の男女約14万人のデータを用いた。対象者の選択基準を5年後調査時のFFQに回答した者とし、除外基準を1)追跡できない者（研究エリア外に在住、研究開始前の転出、外国籍、対象外年齢、重複登録）、2)がんの既往がある者、3)FFQの推定エネルギー量が極端な者とし、約8.9万人を解析対象者とした。研究デザインは、前向きコホート研究（経時的に対象集団を追跡する研究）で、5年後調査時点（1995年または1998年）を起点とし、すい臓がんの罹患の有無を2013年まで追跡した。
FFQによるアクリルアミド摂取量は、アクリルアミド含有量のデータベースを用いて推定した。Cox比例ハザード回帰モデルを用いて、アクリルアミド摂取量の最も少ないグループを基準とし、各グループのハザード比と95％信頼区間を算出した。さらに喫煙状態、体格指数、飲酒量など、アクリルアミドの代謝やすい臓がんの罹患に影響する可能性のある要因について、対象者を層別にして、ハザード比を算出した。
【結果】
15.2年追跡し、すい臓がん576症例が特定された。１日あたりのアクリルアミド摂取量の平均値±標準偏差は、6.92±3.81㎍/dであった。最も摂取量の多いグループは、年齢が若く、喫煙者の割合が多く、コーヒーの摂取量が多い特徴が確認された。最も摂取量の多いグループの調整後のハザード比は、0.83（95%信頼区間: 0.65-1.05, P for trend = 0.07）であり、すい臓がんの罹患リスクは認められなかった。さらに、性別、喫煙状態、体格指数、飲酒量、コーヒー摂取量、緑茶摂取量による層別解析においても関連は認められなかった。
【考察】
FFQより推定したアクリルアミド摂取量とすい臓がんの罹患には関連がないことが示唆された。これまでに日本人を対象とし、発がんリスクを検討した研究では、一貫して関連は認められていない。その一因として、欧米と比較して、日本人のアクリルアミド摂取量が少ないことが考えられる。また日本人のアクリルアミドの主な摂取源は欧米と異なるが、本研究の結果は欧米で得られた知見と同様であることから、アクリルアミド摂取に対する感受性に人種間の差がない可能性を示した。さらに、体格指数や飲酒量などによる層別解析でも、すい臓がんの罹患に関連は認められなかったが、これらの要因はアクリルアミド代謝に影響を与えることが報告されているため、今後バイオマーカーを使用し、これらの影響を考慮した発がんリスクの検討が必要である。
【結論】
日本人において、FFQより推定したアクリルアミド摂取量の多寡によるすい臓がんの罹患には関連がないことが示唆された。
\n【総括】
アクリルアミドは、人への発がんリスクの可能性から、定量的な曝露評価が期待されているが、本研究より、アクリルアミド摂取の個人内変動が高いため、個人の摂取量（絶対値）の推定には、長期間の食事調査日数が必要であることが明らかになった。本研究結果は、食品安全政策におけるアクリルアミドの健康影響を評価する際の曝露評価方法の基礎資料として貢献し得る。
また、アクリルアミド摂取量とすい臓がんのリスクに関する疫学的解析から、関連がないことが確認されたが、これまで世界的にも検討が少なく、アジアでは初の検討となることから、公衆衛生学上の意義が大きいと考えられる。doctoral thesi
A retrospective study (2006-2020) of cytology and biopsy findings in pet rabbits (Oryctolagus cuniculus), ferrets (Mustela putorius furo) and four-toed hedgehogs (Atelerix albiventris) seen at an exotic animal clinic in Tokyo, Japan
Get PDFBackground: Rabbits, ferrets, and four-toed hedgehogs are popular exotic pets, but comprehensive epidemiological studies in these animals have been rarely conducted. The present study aims to clarify the incidence of neoplastic and non-neoplastic diseases in pet rabbits, ferrets and four-toed hedgehogs in Japan. Methods: We histologically/cytologically investigated 1098 samples from 883 rabbits, 812 samples from 521 ferrets and 561 samples from 468 four-toed hedgehogs that were collected at Miwa Exotic Animal Hospital and submitted to the Laboratory of Veterinary Pathology, The University of Tokyo between 2006 and 2020. The examinations of necropsy samples were not included in the present study. Results: Of the 1098 samples from diseased rabbits, 721 (65.7%) were diagnosed as neoplastic and 377 (34.3%) were as non-neoplastic. Uterine adenocarcinoma (21.1%), cutaneous soft tissue sarcoma (15.1%) and mammary gland adenocarcinoma (8.2%) were the most commonly encountered neoplasms. Endometrial hyperplasia (35.8%), testicular atrophy (4.2%) and uterine adenomyosis (3.7%) were the most common non-neoplastic lesions in rabbits. Of the 812 samples from diseased ferrets, 487 (60.0%) were diagnosed as neoplastic and 325 (40.0%) were as non-neoplastic. Adrenocortical tumor (23.2%), lymphoma (19.3%) and pancreatic islet cell tumor (11.5%) were the most commonly encountered neoplasms. Extramedullary hematopoiesis in the spleen (10.5%), lymph node hyperplasia (7.7%) and cholangiohepatitis (4.6%) were the most common non-neoplastic lesions in ferrets. Of the 561 samples from diseased hedgehogs, 338 (60.2%) were diagnosed as neoplastic and 223 (39.8%) were as non-neoplastic. Endometrial stromal tumor and endometrial mixed tumor (23.7%), oral squamous cell carcinoma (13.0%) and cutaneous soft tissue sarcoma (11.5%) were the most commonly encountered neoplasms. Gingivitis/stomatitis (39.5%), endometrial hyperplasia (18.8%) and dermatitis (6.7%) were the most common non-neoplastic lesions in hedgehogs. Conclusions and clinical relevance: Information obtained from the present study will provide a useful reference for veterinarians working with these exotic animals. Based on the literature search, this is the largest-scale retrospective study on disease incidence in hedgehogs.journal articl
Utility of progesterone receptor-ires-Cre to generate conditional knockout mice for uterine study
Get PDFIn mice, the conditional knockout strategy using the Cre-loxP system is useful for various types of research. The Cre mouse line with progesterone receptor promoter (PgrCre) has been widely used to produce specific uterine gene-deficient mice, but in the Cre line, endogenous Pgr gene is replaced by Cre recombinase gene, which makes the breeding of homozygous mice (PgrCre/Cre) difficult because they are infertile. Yang et al. (2013, https://10.1016/j.cell.2013.04.017) reported the generation of another PgriresCre mouse line that still has endogenous Pgr gene, and they inserted Cre recombinase downstream of the Pgr gene via an internal ribosome entry site (IRES). It is possible that this new PgriresCre line would be useful for uterine research as the mice can be bred as homozygotes (PgriresCre/iresCre). Herein, we confirmed the PgriresCre mice effectively directed recombination in the female reproductive tract and was capable of genetic alteration in the endometrium that enables the studies of its uterine function. Our findings demonstrate that the new PgriresCre mouse line is also useful for the generation of uterine-specific knockout mice. The findings using PgriresCre mouse will contribute to the understanding of reproductive systems and diseases in humans and domestic animals.journal articl
Consideration of the Idea of Reverence for the Lives of Animals in the Philosophical Discourse in the Pre-modern Age 1. On the Ideas of Descartes and Others
Get PDFThe idea of reverence for the lives of animals is essential when considering animal ethics, animal rights, and animal welfare. A central issue in these topics is the necessity of sacrificing animals’ lives for industry and consumption. The sacrifice is made as a result of the utilization of animal resources in three main ways: the use of livestock animals for food, the use of animals as subjects for experiments and the use of wild animals for food and other purposes.
In Western philosophy, the existence of an animal’s soul has been frequently debated. However, although animals have been associated with traditional rituals, sacred symbols of myths or religion, and the objects of worship for faith, it is not possible to clearly prove the existence of an animals’ emotions and soul. In Greek philosophy and the philosophical discourse of Europe in the pre-modern age, animals were regarded as lower living creatures owing to their lack of an ability to reason. Humans, on the other hand, were considered to exist at a higher level due to their rationality and possession of mind with morality.
René Descartes’s idea on animals is a remarkably representative theory of “animals as machines,” and his contemporaries, Pascal and Spinoza, also regarded animals as lower beasts. Although the values and views on animals expressed by Descartes’ are widely considered to be inappropriate in the 21st century, as the concept of animal right has taken hold, it is important to re-consider these philosophers’ ideas about animals when considering another concept, animal ethics. Leibnitz provided a different outlook, recognizing the abilities of animals and considering the existence of their souls, paves thereby paving the way for animal ethics.P(論文)原著論文application/pdfORIGINAL ARTICLEdepartmental bulletin pape