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排序方式: 共有3026条查询结果,搜索用时 15 毫秒
1.
目的 观察形觉剥夺性高度近视(form deprivation high myopia,FDHM)豚鼠巩膜形态变化,探讨缺氧诱导因子-1α(hypoxia-inducible factor-1α,HIF-1α)及氧自由基在高度近视中的作用。方法 将豚鼠适应性饲养1周后,随机分为空白对照组(25只)和模型组(25只)。模型组豚鼠右眼行眼睑缝合,所有模型组豚鼠均选择右眼作为FDHM组,对侧眼为自身对照组。空白对照组豚鼠不做任何处理。于造模前及造模后8周采用检影镜测量屈光度,A超进行生物测量。形觉剥夺8周以后处死豚鼠,观察巩膜形态和超微结构的变化,测定巩膜HIF-1α相对表达量,超氧化物歧化酶(superoxide dismutase,SOD)活力及丙二醛(malondialdehyde,MDA)的含量。结果 豚鼠形觉剥夺8周以后,FDHM组屈光度从(+3.59±0.33)D变为(-7.96±0.55)D,明显高于空白对照组(+0.89±0.32)D、自身对照组(-0.55±0.49)D(均为P<0.05);玻璃体腔深度为(4.12±0.13)mm明显高于空白对照组(3.71±0.23)mm和自身对照组(3.93±0.04)mm(均为P<0.05);眼轴长度为(8.93±0.22)mm明显长于空白对照组(7.95±0.37)mm和自身对照组(8.01±0.15)mm(均为P<0.05)。巩膜组织明显变薄,细胞外基质增多,成纤维细胞密度降低,胶原纤维平均直径减小。FDHM组巩膜中HIF-1α相对表达量、MDA含量明显高于空白对照组和自身对照组,SOD活力明显低于空白对照组和自身对照组(均为P<0.05)。结论 形觉剥夺8周后,豚鼠FDHM眼近视度数明显增加,玻璃体腔深度增加,眼轴延长,巩膜形态发生病理性变化;HIF-1α、SOD、MDA可能参与了FDHM的形成。 相似文献
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The objective of the present study was to evaluate the effects of low-molecular-weight chitosan (LMWC) on the growth performance, immune responses and intestinal health of weaned pigs challenged by enterotoxigenic Escherichia coli (ETEC). A total of 32 weaned pigs were randomly allocated to four treatments: non-challenged (fed with basal diet), ETEC-challenged (fed with basal diet) and ETEC-challenged plus 50 or 100 mg/kg LMWC supplementation, respectively. After 11 days feeding, the non-challenged pigs were infused with sterilised Luria–Bertani culture, while the remaining pigs were infused with 2.6 × 1011 colony-forming units of ETEC. At 3 days post-challenge, all pigs were administered d-xylose at 0.1 g/kg body weight. One hour later, blood samples were obtained, and the pigs then euthanised to collect intestinal samples. Data showed that only 100 mg/kg LMWC supplementation attenuated (P < 0.05) the average daily gain reduction caused by ETEC. Furthermore, besides the decreased (P < 0.05) serum tumour necrosis factor-α and immunoglobulin (Ig) G concentrations detected in ETEC-challenged pigs supplemented with LMWC at 50 or 100 mg/kg, the higher dose (100 mg/kg) also decreased (P < 0.05) the serum IgM concentration and increased (P < 0.05) the villus height and villus height-to-crypt depth ratio in both the jejunum and ileum, and the sucrase activity in the ileal mucosa. Moreover, LMWC supplementation (50 or 100 mg/kg) in ETEC-challenged pigs elevated (P < 0.05) the mRNA levels of jejunal mucosal peptide transporter 1 and ileal mucosal peptide transporter 1, divalent metal transporter 1 and zinc transporter 1, and decreased (P < 0.05) the ileal and caecal E. coli abundances, while 100 mg/kg LMWC additionally elevated (P < 0.05) the ileal Bacillus abundance, and caecal and colonic Bifidobacterium abundances. These results suggest that LMWC helps alleviate ETEC-induced growth retardation in weaned pigs, which could be associated with the inhibition of the immune responses and improved intestinal health. 相似文献
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Yadnyavalkya Patil 《Gut microbes》2020,11(3):310-334
ABSTRACT It is well established that pig gut microbiota plays a critical role in maintaining metabolic homeostasis as well as in a myriad of physiological, neurological and immunological functions; including protection from pathogens and digestion of food materials – some of which would be otherwise indigestible by the pig. A rich and diverse gut microbial ecosystem (balanced microbiota) is the hallmark of good health; while qualitative and quantitative perturbations in the microbial composition can lead to development of various diseases. Alternatively, diseases caused by stressors or other factors have been shown to negatively impact the microbiota. This review focuses primarily on how commensal microorganisms in the gastrointestinal tract of pigs influence biochemical, physiological, immunological, and metabolic processes within the host animal. 相似文献
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《Vaccine》2015,33(49):6977-6982
Heterosubtypic immunity is defined as immune-mediated (partial) protection against an influenza virus induced by an influenza virus of another subtype to which the host has not previously been exposed. This cross-protective effect has not yet been demonstrated to the newly emerging avian influenza A viruses of the H7N9 subtype. Here, we assessed the induction of protective immunity to these viruses by infection with A(H1N1)pdm09 virus in a newly developed guinea pig model. To this end, ten female 12–16 week old strain 2 guinea pigs were inoculated intratracheally with either A(H1N1)pdm09 influenza virus or PBS (unprimed controls) followed 4 weeks later with an A/H7N9 influenza virus challenge. Nasal swabs were taken daily and animals from both groups were sacrificed on days 2 and 7 post inoculation (p.i.) with A/H7N9 virus and full necropsies were performed.Nasal virus excretion persisted until day 7 in unprimed control animals, whereas only two out of seven H1N1pdm09-primed animals excreted virus via the nose. Infectious virus was recovered from nasal turbinates, trachea and lung of all animals at day 2 p.i., but titers were lower for H1N1pdm09-primed animals, especially in the nasal turbinates. By day 7 p.i., relatively high virus titers were found in the nasal turbinates of all unprimed control animals but infectious virus was isolated from the nose of only one of four H1N1pdm09-primed animals.Animals of both groups developed inflammation of variable severity in the entire respiratory tract. Viral antigen positive cells were demonstrated in the nasal epithelium of both groups at day 2. The bronchi(oli) and alveoli of unprimed animals showed a moderate to strong positive signal at day 2, whereas H1N1pdm09-primed animals showed only minimal positivity. By day 7, only viral antigen positive cells were found after H7N9 virus infection in the nasal turbinates and the lungs of unprimed controls. Thus infection with H1N1pdm09 virus induced partially protective heterosubtypic immunity to H7N9 virus in (isogenic) guinea pigs that could not be attributed to cross-reactive virus neutralizing antibodies. 相似文献
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目的 研究30 d重复皮肤涂抹利多卡因凝胶对豚鼠产生的毒性反应。方法 利多卡因凝胶高、中、低剂量(40、20、10 g/kg)连续皮肤涂抹给药30 d,整个试验期间观察动物的临床症状,测定体质量和摄食量,分别于给药30 d及停药后14 d取部分豚鼠进行血液学、血清生化学、脏器系数和病理组织学检查。结果 豚鼠未出现因给药而引起的异常症状,各给药组豚鼠体质量增长和摄食正常;利多卡因凝胶在10、20 g/kg剂量下,豚鼠血液学、血清生化学、脏器系数和病理组织学等均未见毒理学意义的异常改变;40 g/kg利多卡因凝胶导致豚鼠血清K+水平,肾上腺质量及系数明显增高(P<0.05),但脏器未出现毒性病理改变;停药14 d后,上述异常指标恢复正常,也未见其他延迟毒性。结论 在本试验条件下,皮肤涂抹利多卡因凝胶对豚鼠无明显毒性,无毒反应剂量为20 g/kg。 相似文献
8.
Aleksandra Wo
niak Dagmara Miek Piotr Bska Tomasz Stadejek 《Transboundary and Emerging Diseases》2019,66(4):1454-1461
PCV2 is globally spread pathogen involved in a number of diseases (PCVD). Commonly used vaccines against PCV2 are proved to be highly efficacious. The role of recently discovered PCV3 for pig health and interference with PCV2 remains unknown. The study performed on serum samples from seven farms vaccinated against PCV2 and four non‐vaccinated showed very low prevalence of PCV2 viremia in the former (3 out of 106 positive serum pools) and high prevalence of PCV2 viremia in the latter (35 out of 60 positive pools). Mean log10 PCV2 genome equivalents were lower in vaccinated farms (4.8 ± 0.6 log10 copies/ml) than in non‐vaccinated farms (6.3 ± 1.3 log10 copies/ml). PCV3 was detected in 31 out of 106 and 12 out of 60 serum pools from vaccinated and non‐vaccinated farms, respectively. Mean log10 PCV3 genome equivalents were significantly (p < 0.05) lower in vaccinated farms (3.9 ± 0.8 log10 copies/ml) than in non‐vaccinated farms (4.4 ± 0.6 log10 copies/ml). Concurrent PCV2 and PCV3 infection was rare and found only in 1 out of 529 and 4 out of 292 individual serum samples from vaccinated and non‐vaccinated farms, respectively. Our results showed lack of impact of PCV3 circulation on PCV2 vaccine efficacy. On the other hand, intensive PCV2 circulation and high viremia detected in non‐vaccinated farms did not seem to increase the level of PCV3 infection. 相似文献
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目的 探索豚鼠耳蜗基底膜振动测试的方法。方法 用戊巴比妥钠腹腔注射麻醉豚鼠后,腹侧切口,逐层切开皮肤,分离肌肉,可见听泡位于豚鼠下颌骨内侧深面,钝性分离听泡表面的肌肉组织,暴露听泡,用电钻将听泡打开,可见螺旋形耳蜗结构,辨认基底膜所在的部位。用电钻在需要开孔的骨壁上轻磨一个环形的凹陷,待足够薄弱的时候用尖头的刀片挑开骨片。用具有微细尖端的不锈钢针蘸取少量反光微珠,放置在基底膜上。然后用激光多普勒测振仪(laser doppler vibrometer,LDV)测量基底膜在外耳道纯音激励下的振动。结果 用该方法测量了豚鼠耳蜗基底膜在不同频率声波激励下的响应曲线。结论 该方法可进行豚鼠耳蜗基底膜振动的离体实验,但活体的振动测试尚需进一步的探索。 相似文献
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