排序方式： 共有25条查询结果，搜索用时 19 毫秒
1.
Telomerase adds new telomeric sequences to the end of chromosomal DNA in order to overcome the end-replication problem. The upregulation of telomerase activity in tumours has been reported in humans and some mammals and is considered to be a tumour marker; however, such activity has not been investigated in cows. Therefore, we investigated telomerase activity in bovine leukaemia, the most common tumour in cows and its relationship with the bovine leukaemia virus (BLV) infection, which is the major cause of leukaemia. Telomerase activity was detected in 25 of 29 bovine leukaemia tissue samples. In peripheral blood lymphocytes (PBL) from BLV-infected cases that did not develop the tumour, telomerase activity was detected in 11 of 71 cases (15.5%). When these cases were classified based on serological tests and the peripheral blood lymphocyte count, the telomerase activity was observed to be the highest in the seropositive, non-lymphoproliferative (PBL<8000 microl(-1)) cases (three of seven cases, 42.9%), and not observed in the lymphoproliferative cases (PBL<16,000 microl(-1)) except in one case. Although the precise pathogenesis of BLV-related diseases remains obscure, persistent lymphocytosis is considered as a pre-neoplastic state. In contrast, our results suggested that given the fact that telomerase activity indicates tumour development, the aleukaemic stage could be defined as the 'pre-neoplastic state'. In conclusion, similar to many tumours in humans, telomerase activity was detected in bovine leukaemia; further, this activity can be a potentially useful prediction marker for tumour development and/or a good therapeutic target. 相似文献
2.
Yoshio MINAMI Seiko YAMANO Minako KAWAI Atsushi HIRAGA Hirofumi MIYATA 《Journal of Equine Science》2009,20(3):33-40
To find a new parameter indicating muscle fitness in Thoroughbred horses, we examined
time-dependent recovery of glycogen content and sarcoplasmic reticulum (SR)
Ca2+-ATPase activity of skeletal muscle after intensive treadmill running.
Two repeated 50-sec running sessions (13 m/sec) were performed on a flat treadmill
(approximately 90%VO2max). Muscle samples of the middle gluteal muscle were
taken before exercise (pre) and 1 min, 20 min, 60 min, and 24 hr after exercise. Muscle
fiber type composition was determined in the pre muscle samples by immunohistochemical
staining with monoclonal antibody to myosin heavy chain. SR Ca2+-ATPase
activity of the muscle and glycogen content of each muscle fiber type were determined with
biochemical analysis and quantitative histochemical staining, respectively. As compared to
the pre value, the glycogen content of each muscle fiber type was reduced by 15–27% at 1
min, 20 min, and 60 min after the exercise and recovered to the pre value at 24 hr after
exercise test. These results indicate that 24 hr is enough time to recover glycogen
content after short-term intensive exercise. The mean value of the SR
Ca2+-ATPase activity showed a slight decrease (not significant) immediately
after exercise, and complete recovery at 60 min after exercise. There were no significant
relationship between the changes in glycogen content of each muscle fiber type and SR
Ca2+-ATPase. Although further studies are needed, SR Ca2+-ATPase
is not a useful parameter to detect muscle fitness, at least in Thoroughbred horses. 相似文献
3.
Seiko YAMANO Minako KAWAI Yoshio MINAMI Atsushi HIRAGA Hirofumi MIYATA 《Journal of Equine Science》2010,21(4):59-65
We evaluated differences in muscle fiber recruitment patterns between continuous and
interval training to develop an optimal training program for Thoroughbred horses. Five
well trained female thoroughbred horses (3–4 years old) were used. The horses performed
two different exercises on a 10% inclined treadmill: 90%VO2 max for 4 min
(continuous) and 90% VO2 max for 2 min × 2 times with 10-min interval
(interval). Muscle samples were obtained from the middle gluteal muscle before and
immediately after the exercises. Four muscle fiber types (type I, IIA, IIA/X, and IIX)
were immunohistochemically identified, and the optical density of periodic acid Schiff
staining (OD-PAS) in each fiber type and glycogen content of the muscle sample were
determined by quantitative histochemical and biochemical procedures, respectively. No
significant differences were found in the OD-PASs and glycogen contents between the
continuous and interval exercises, but the decreases in OD-PAS of fast-twitch muscle
fibers were obvious after interval as compared to continuous exercise. Interval exercise
may be a more effective training stimulus for the glycolytic capacity of fast-twitch
muscle fiber. The data about muscle fiber recruitment can provide significant insights
into the optimal training program not only for thoroughbred horses, but also for human
athletes. 相似文献
4.
Doi Y Tamano S Kawabe M Sano M Imai N Nakashima H Furukawa F Hagiwara A Otsuka M Shirai T 《Journal of toxicologic pathology》2011,24(4):207-213
This study was conducted to determine the concordance of results for a pair of structural
isomers, 2-nitropropane (2-NP) and 1-nitropropane (1-NP), using the rat medium-term liver
carcinogenesis bioassay (Ito test) and previously published long-term carcinogenicity
tests. Male F344 rats were given a single intraperitoneal injection of DEN (200 mg/kg
b.w.) to initiate hepatocarcinogenesis. After 2 weeks, they received per os 0, 0.8, 4 or
20 mg/kg/day of 2-NP or 1-NP six times a week and were subjected to two-thirds partial
hepatectomy at week 3. Non-initiated groups receiving 0 or 20 mg/kg/day were also
included. The animals were sacrificed for quantitative analysis of GST-P-positive foci at
week 8. With the highest dose of 2-NP, significantly increased numbers and areas of
GST-P-positive foci were demonstrated as compared with the respective control but were not
noted with 1-NP. In the non-DEN-initiated groups, many small GST-P-positive foci of less
than 0.2 mm in diameter were also induced in the rats treated with 2-NP at 20 mg/kg/day
but were lacking with 1-NP. These results strongly support that 2-NP is a complete
hepatocarcinogen with a potent initiation activity, whereas 1-NP is not. 相似文献
5.
Seiko Yoshikawa Hidehiro Takahashi Yasuko Sasada Hidetoshi Mochizuki 《Soil Science and Plant Nutrition》2013,59(6):898-909
AbstractThe aim of this study was to evaluate the impact of land use on nitrate nitrogen (NO3-N) in shallow groundwater (G-N) and total nitrogen (N) in river water (R-N). The study area consisted of 26 watersheds (1342 km2) covering 72% of Kagawa Prefecture in Japan. We estimated G-N specific concentrations, which showed the magnitude of the upland fields, paddy fields, forests and urban land-use contributions to watershed-mean G-N. G-N specific concentrations were gained as partial regression coefficients using a multiple regression analysis of the watershed-mean G-N concentrations and the land-use ratios in each of the 26 watersheds. The results showed that the G-N specific concentration, which was gained as the partial regression coefficient for the multiple regression analysis, was 15.2 mg L?1, 10.3 mg L?1, 2.3 mg L?1 and 2.5 mg L?1 for the upland fields, paddy fields, forests and urban land-use types, respectively. R-N pollution load runoff to the river mouth was calculated by multiplying R-N specific concentration (previously reported) by river flow at the river mouth. Similarly, G-N pollution load arrival to groundwater was calculated by multiplying G-N specific concentration by the groundwater flow. The R-N pollution load runoff was 19.3 kg ha?1 y?1, 7.7 kg ha?1 y?1, 1.7 kg ha?1 y?1 and 7.6 kg ha?1 y?1, while the G-N pollution load arrival was 7.3 kg ha?1 y?1, 5.0 kg ha?1 y?1, 1.1 kg ha?1 y?1 and 1.2 kg ha?1 y?1, for upland fields, paddy fields, forests and urban areas, respectively. These results showed that the N in river water and groundwater was derived mainly from runoff and leaching from croplands. Therefore, the relationships between watershed-mean non-absorbed, applied nitrogen (NAA-N: nitrogen applied to cropland via fertilizer and manure without being absorbed by crops), R-N concentration and watershed-mean G-N concentration were investigated. A curvilinear correlation was observed between NAA-N and R-N concentrations (r2 = 0.68) except for one small, high-density, urban watershed, and a weak linear correlation was observed between NAA-N and G-N concentrations (r2 = 0.42). 相似文献
6.
Shibata M Otake M Tsuchiya S Chikyu M Horiuchi A Kawarasaki T 《The Journal of reproduction and development》2006,52(5):583-590
Somatic cell cloning is expected to be a valuable method for conserving genetic resources in pigs. In this study, we compared the reproductive and growth performance of Jin Hua cloned pigs with that of naturally bred Jin Hua pigs. In addition, we generated offspring from the cloned sows and examined the productivity and quality of meat in the progeny. The birth weights and growth rates of somatic cell-cloned pigs were similar to those of Jin Hua pigs. The cloned pigs reached puberty very early, and this is typical of the Jin Hua breed. Furthermore, reproductive performance, in terms of traits such as gestation period, litter size, and raising rate in the cloned pigs were similar to Jin Hua pigs. Although the offspring of the cloned (OC) pigs had lower birth weights than the Jin Hua breed, the daily weight gain of the OC pigs was significantly higher, especially at the finishing stage. The carcass quality of the OC pigs had similar characteristics to the Jin Hua breed, namely thick back fat and a small loin area. Furthermore, the meat qualities of the OC pigs were similar to those of Jin Hua pigs in terms of intramuscular fat content and tenderness. These results demonstrate that cloned pigs and their offspring were similar to the Jin Hua breed in most of the growth, reproductive, and meat productive performances. This strongly suggests that pigs cloned from somatic cell nuclei have the potential to be a valuable genetic resource for breeding. 相似文献
7.
Min Wei Anna Kakehashi Shotaro Yamano Seiko Tamano Tomoyuki Shirai Hideki Wanibuchi Shoji Fukushima 《Journal of toxicologic pathology》2012,25(3):209-214
The purposes of the present study were to evaluate the hepatocarcinogenicity of
concurrent treatment of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline
(MeIQx) and diethylnitrosamine (DEN) in rats and to determine whether no effect levels of
combinations of these two different structural categories of genotoxic hepatocarcinogens
exist. Two 16-week rat hepatocarcinogenesis assays were performed using a total of 790
male F344 rats. In experiment 1, we evaluated the effects of concurrent treatment of a
subcarcinogenic dose of DEN on rat hepatocarcinogenesis induced by various doses of MeIQx.
In experiment 2, we determined hepatocarcinogenicities of combinations of MeIQx and DEN at
subcarcinogenic doses, low carcinogenic doses and high carcinogenic doses. Quantitative
analyses of glutathione S-transferase placental form (GST-P)-positive
foci, a preneoplastic lesion of the liver in rats, revealed that concurrent treatment with
subcarcinogenic doses of DEN did not enhance MeIQx-induced rat hepatocarcinogenicity. We
also found that concurrent treatment with combinations of subcarcinogenic doses of DEN and
MeIQx was not hepatocarcinogenic, indicating that the combined effects of subcarcinogenic
doses of DEN and MeIQx were neither additive nor synergistic. Moreover, concurrent
treatment with low carcinogenic doses of these 2 carcinogens did not show additive or
synergistic effects. Synergetic effects were observed only in rats coadministered high
carcinogenic doses of the 2 carcinogens. These results demonstrate the existence of no
effect levels of combinations of these 2 genotoxic hepatocarcinogens, and provide new
evidence supporting our idea that there is a threshold, at least a practical threshold,
that should be considered when evaluating the risk of genotoxic carcinogens. 相似文献
8.
9.
Yoshimura T Kuribara H Kodama T Yamata S Futo S Watanabe S Aoki N Iizuka T Akiyama H Maitani T Naito S Hino A 《Journal of agricultural and food chemistry》2005,53(6):2060-2069
Seven types of processed foods, namely, cornstarch, cornmeal, corn puffs, corn chips, tofu, soy milk, and boiled beans, were trial produced from 1 and 5% (w/w) genetically modified (GM) mixed raw materials. In this report, insect resistant maize (MON810) and herbicide tolerant soy (Roundup Ready soy, 40-3-2) were used as representatives of GM maize and soy, respectively. Deoxyribonucleic acid (DNA) was extracted from the raw materials and the trial-produced processed food using two types of methods, i.e., the silica membrane method and the anion exchange method. The GM% values of these samples were quantified, and the significant differences between the raw materials and the trial-produced processed foods were statistically confirmed. There were some significant differences in the comparisons of all processed foods. However, our quantitative methods could be applied as a screening assay to tofu and soy milk because the differences in GM% between the trial-produced processed foods and their raw materials were lower than 13 and 23%, respectively. In addition, when quantitating with two primer pairs (SSIIb 3, 114 bp; SSIIb 4, 83 bp for maize and Le1n02, 118 bp; Le1n03, 89 bp for soy), which were targeted within the same taxon specific DNA sequence with different amplicon sizes, the ratios of the copy numbers of the two primer pairs (SSIIb 3/4 and Le1n02/03) decreased with time in a heat-treated processing model using an autoclave. In this report, we suggest that the degradation level of DNA in processed foods could be estimated from these ratios, and the probability of GM quantification could be experimentally predicted from the results of the trial producing. 相似文献
10.
以薄壳山核桃‘Shaoxing’和‘Pawnee’的花粉为材料,采用MTT染色法对其4个散粉时期的花粉活力及不同储藏条件下的花粉活力变化进行了研究,筛选出最佳花粉收集时期和最佳储藏条件。结果表明：（1）‘Shaoxing’和‘Pawnee’不同散粉时期花粉活力由高到低变化规律都为：散粉盛期>散粉初期>即将散粉期>散粉末期。（2）‘Shaoxing’和‘Pawnee’各散粉期的花粉活力随阴干时间的延长而下降,其中‘Shaoxing’盛花期、‘Pawnee’散粉初期的花粉在0~4 d的短时间阴干储藏下降速率最慢,96 h后分别仍有45.70%和64.31%;（3）低温、干燥的储藏条件有利于‘Shaoxing’和‘Pawnee’花粉活力的保持,2个品种的花粉在不同储藏条件下都表现为：?80 ℃密封干燥>?80 ℃密封>4 ℃密封干燥>4 ℃密封>常温密封干燥>常温密封,其中2个品种的花粉在?80 ℃条件储藏30 d后活力仍保持在60%以上,而常温条件储藏30 d后的花粉活力低于20%,储藏80 d就完全失去活力。 相似文献