A simulation study for a linear measurement error model when error variances vary between measurements     

Yasutaka?ChibaEmail author  Yutaka?Matsuyama  Tosiya?Sato  Isao?Yoshimura 《Journal of Agricultural, Biological & Environmental Statistics》2005,10(1):118-130

When predicting scores in the Draize eye irritation test based on measurements of in vitro alternative tests, we are often faced with estimating parameters in a linear measurement error model with heterogeneous error variances. This article proposes a new statistical method for parameter estimation to address this issue. The proposed method is an extension of an earlier proposal that applied a linear measurement error model with homogeneous error variances, to cases with heterogeneous error variances. A simulation study to examine the performance of the proposed method was conducted in a framework that was adaptable to the data, which was obtained in a validation study of alternative methods to animal experiments conducted in Japan. The proposed method reduced the biases of estimates in comparison with an ordinary regression analysis method and three other methods under the assumption of homogeneous error variances. Although the proposed method did not fit the real data well, the resulting prediction formula was far better than those obtained by other methods.  相似文献   

人工合成甘蓝型油菜的繁育特性与试管繁殖   总被引：5，自引：0，他引：5  

卢长明  肖玲  张斌  加藤正弘  沈明珍 《中国油料作物学报》2003,25(4):5-10

通过甘蓝品种(2n=18，CC)与白菜品种(2n=20，AA)杂交并借助胚珠培养和染色体加倍，获得一系列人工甘蓝型油菜新品系。对18个人工合成甘蓝型油菜新品系的花粉育性、自交结实性、异交结实性等研究表明，人工油菜品系花期自交不结实或结实率很低。蕾期自交一朵花平均获3．6粒种子，平均结角率为19．7％。但是，人工甘蓝型油菜无论作父本还是作母本与天然甘蓝型油菜杂交的结实率都较高。以人工油菜作父本与天然油菜杂交。42个组合平均杂交一朵花获得10．3粒杂交种子；以人工油菜作母本与天然油菜杂交，15个组合平均杂交一朵花获得8．5粒杂交种子。分析结果表明。本试验的人工油菜品系具有很强的自交不亲和性，蕾期自交结实率也较低，但对异交结实影响不大，因此可以直接用于杂种生产。试验对自交结实特别困难的5个人工甘蓝型油菜新品系进行了试管繁殖，采取子叶、下胚轴和茎尖联合培养方式。22株无菌苗经过2个月快繁，获得260株苗。平均繁殖系数为12．4。不同基因型繁殖系数差异较大。变幅为3．3～21．0。  相似文献   

Suspected spontaneous hyperadrenocorticism in a young experimental beagle dog     

Ryo D. Obara  Yuki Kato  Yoshiji Asaoka  Miho Mukai  Keigo Matsuyama  Kae Fujisawa  Minako Tajiri  Tamio Fukushima  Mikinori Torii 《Journal of toxicologic pathology》2021,34(3):261

A 6-month-old female beagle dog, assigned to the low-dose group in a toxicity study, was evaluated for compound toxicity, and spontaneous hyperadrenocorticism was suspected. The animal had an externally apparent distended abdomen on clinical examination upon arrival. Pre-dose clinical pathology showed slightly higher erythroid parameters and stress leukogram on hematology; plasma biochemistry showed higher total protein, gamma-glutamyl transferase, total cholesterol, and triglyceride levels than the reference data. On necropsy, a prominent increase in adipose tissues of the subcutis and abdomen and increased weight of the adrenal gland and liver were observed. Histopathology revealed diffuse hyperplasia of adrenocortical cells in the zona fasciculata and reticularis, cortical atrophy of the thymus, and abundant glycogen accumulation in the hepatocytes. These findings were incidental and not test-substance-related. Electron microscopy of the adrenocortical cells in the zona fasciculata revealed decreased typical translucent lipid droplets, increased electron-dense lipid droplets, and abundant smooth endoplasmic reticulum and lysosomes. Additionally, increased numbers of various sizes and forms of mitochondria with tubular, vesicular, or lamellar cristae compared to that of normal animals were observed. These ultrastructural characteristics of the adrenocortical cells suggested hyperfunction. The pre-dose plasma cortisol levels were slightly higher than those of other females assigned to the toxicity study, while plasma adrenocorticotropic hormone levels were within the normal range. These findings indicate that hyperadrenocorticism is a possible cause of the systemic changes in this case.  相似文献   

Thioacetamide-induced Hepatocellular Necrosis Is Attenuated in Diet-induced Obese Mice     

Makoto Shirai  Shingo Arakawa  Hiroaki Miida  Takuya Matsuyama  Junzo Kinoshita  Toshihiko Makino  Kiyonori Kai  Munehiro Teranishi 《Journal of toxicologic pathology》2013,26(2):175-186

To assess modification of thioacetamide-induced hepatotoxicity in mice fed a high-fat diet, male C57BL/6J mice were fed a normal rodent diet or a high-fat diet for 8 weeks and then treated once intraperitoneally with thioacetamide at 50 mg/kg body weight. At 24 and 48 hours after administration, massive centrilobular hepatocellular necrosis was observed in mice fed the normal rodent diet, while the necrosis was less severe in mice fed the high-fat diet. In contrast, severe swelling of hepatocytes was observed in mice fed the high-fat diet. In addition, mice fed the high-fat diet displayed more than a 4-fold higher number of BrdU-positive hepatocytes compared with mice fed the normal rodent diet at 48 hours after thioacetamide treatment. To clarify the mechanisms by which the hepatic necrosis was attenuated, we investigated exposure to thioacetamide and one of its metabolites, the expression of CYP2E1, which converts thioacetamide to reactive metabolites, and the content of glutathione S-transferases in the liver. However, the reduced hepatocellular necrosis noted in mice fed the high-fat diet could not be explained by the differences in exposure to thioacetamide or thioacetamide sulfoxide or by differences in the expression of drug-metabolizing enzymes. On the other hand, at 8 hours after thioacetamide administration, hepatic total glutathione in mice fed the high-fat diet was significantly lower than that in mice fed the normal diet. Hence, decreased hepatic glutathione amount is a candidate for the mechanism of the attenuated necrosis. In conclusion, this study revealed that thioacetamide-induced hepatic necrosis was attenuated in mice fed the high-fat diet.  相似文献   

Female preference did not evolve under laboratory conditions in the solanaceous fruit fly Bactrocera latifrons     

Takashi Kuriwada  Norikuni Kumano  Keiko Shiromoto  Dai Haraguchi  Takashi Matsuyama  Tsuguo Kohama 《国际虫害防治杂志》2014,60(3):160-165

Sterile insect technique (SIT) is widely used to eradicate target pest species. Its effectiveness depends on the ability of released sterile males to mate with wild females. In pest species with a female choice mating system, there is potential for female preference to evolve in the wild population in view of the resulting zero-fitness in females that mate with sterile males. The evolution of female preference against sterile males can, therefore, reduce the efficiency of the SIT as the likelihood decreases that sterile males will mate with wild females. We examined this experimentally by using the solanaceous fruit fly Bactrocera latifrons, a serious pest of solanaceous crops, by allowing female preference in mass-reared fruit flies to select between fertile and sterile males over 12 generations. However, this did not generate a rapid evolutionary response. Also the remating rate of females did not increase, even when the first mating partner was a sterile male. We discuss the implication of the results for the eradication project by the SIT program.  相似文献   

Predicting soil water movement in converted soybean fields under high moisture condition     

Kato  Chihiro  Sasaki  Choichi  Endo  Akira  Matsuyama  Nobuhiko  Nishimura  Taku 《Paddy and Water Environment》2019,17(2):55-61

Paddy and Water Environment - Crops adapt to variable soil moisture by varying the distribution of their roots and patterns of water absorption. Meanwhile, proper numerical model for predicting...  相似文献   

Effects of synthetic kisspeptin peptides and GnRH analogue on oocyte growth and circulating sex steroids in prepubertal female chub mackerel (Scomber japonicus)          下载免费PDF全文

Sethu Selvaraj  Hirofumi Ohga  Mitsuo Nyuji  Hajime Kitano  Naoki Nagano  Akihiko Yamaguchi  Michiya Matsuyama 《Aquaculture Research》2015,46(8):1866-1877

In recent years, kisspeptin peptides, encoded by kiss genes have been used to manipulate reproductive processes in farmed animals, including fish. Our previous studies demonstrated that the chub mackerel brain expresses kiss1 and kiss2 and intramuscular injection of synthetic Kiss1 pentadecapeptide (Kiss1‐15) but not Kiss2 dodecapeptide (Kiss2‐12) accelerates spermatogenesis in prepubertal male chub mackerel (Scomber japonicus). In the present study, we evaluated their effects in prepubertal female chub mackerel. The gonadosomatic index (GSI) values of experimental fish did not show any significant changes. Condition factor (CF) values increased significantly in Kiss1‐15 treated fish, in comparison with control and GnRH analogue (GnRHa) injected fish. Histologically, only perinucleolar oocytes were found in all experimental fish. However, Kiss and GnRHa treated fish showed a significant increase in the perinucleolar oocyte diameter, in comparison with the control fish. Gene expression analyses revealed decreased expression of gnrh1 in the telencephalon‐preoptic region of the brain of Kiss2‐12 and GnRHa injected fish, in comparison with control fish. In contrast, GnRHa injected fish exhibited higher levels of fshβ in the pituitary, with no changes in the levels of lhβ among different treatments. Levels of circulating sex steroids, testosterone, and estradiol‐17β were significantly higher in Kiss1‐15 injected fish, in comparison with control fish. These results indicate that synthetic kisspeptin peptides and GnRHa can induce oocyte growth in prepubertal female chub mackerel.  相似文献   

The role of a specific antibody against Flavobacterium psychrophilum infection in ayu sweetfish,Plecoglossus altivelis altivelis (Temminck & Schlegel, 1846)          下载免费PDF全文

G Kato  K Suzuki  T Sakai  M Kawakami  T Takano  T Matsuyama  C Nakayasu 《Journal of fish diseases》2015,38(1):107-112

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Flow cytometric analysis of thymocyte subpopulations in mice after whole-body X-irradiation.     

S Oka  K Kubo  S Matsuyama  Y Takamori 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》1999,61(6):709-712

To determined the cellular kinetics of thymocyte subpopulations in DBA1 mice after whole-body 6.8 Gy X-irradiation, they were analyzed for the expression of several cell surface antigens using flow cytometry. The results show that i) The majority of thymocytes rapidly depleted by irradiation was CD4+8+ cells. ii) radioresistant CD4+8- and CD4-8+ survived 18-48 hr after X-irradiation were considered to be relatively mature type, since they expressed high levels of CD3 and LECAM-1. iii) CD3-positive cells were detected in CD4-8- cells at 72 hr after irradiation.  相似文献   

B220 is expressed on apoptotic thymocytes induced by X-irradiation.     

S Oka  K Kubo  S Matsuyama  Y Takamori 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》1999,61(4):337-341

CD45 is cell surface glycoprotein and expressed on all haematopoietic cells except mature erythrocytes and platelets. Eight isoforms of CD45 are generated by alternative splicing of exons 4-6. B220 including all three exons is expressed specifically on pan-B cell lineage. Recently, it was reported that B220 was expressed on apoptotic T cells induced by staphylococcal enterotoxin B (SEB). In the present study, we investigated the expression of B220 on murine thymocytes after whole-body X-irradiation. We used the forward light scattering of flow cytometry as a parameter of cell size, and defined two populations; FSChigh (normal cell size) and FSClow (correspond to apoptotic cell in size) fraction. B220+ cells in FSChigh fraction reached a maximum value (35%) at 18 hr after irradiation. In FSClow fraction, 40-60% cells were positive for B220 at any time points. These results suggest that B220 is expressed on thymocytes in the pre-apoptotic stage, because B220 was expressed on not only FSClow cells but also FSChigh cells.  相似文献