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1.
为了充分发挥瘤胃的发酵功能,研究人员一直致力于瘤胃微生态的研究。随着分子生物学技术的发展,研究瘤胃微生态学采用人工培养为基础的传统方法正在被以核酸为基础的分子生物学技术迅速取代。分子生物学技术对瘤胃微生态的研究可从微生物多样性、区系结构、功能几方面进行概括。本文将从上述几方面论述分子生物学技术在瘤胃微生态研究中的应用及最新研究进展。  相似文献   

2.
促渗剂促进药物透皮吸收机理的研究进展   总被引:10,自引:0,他引:10  
综述了促渗剂促进药物透皮吸收机理的研究概况,着重介绍了氮酮、油酸和萜烯等常用促渗剂的促渗机理研究进展,并提出透皮吸收机理研究发展趋势,为该领域进一步深入研究提供参考.  相似文献   

3.
This study was conducted to describe the ultrasonographic appearance and technique for the evaluation of sciatic nerve (ScN) in cats. An anatomical study was carried out using six feline cadavers to determine anatomic landmarks. An ultrasonographic 'in vitro' study was performed using eight pelvic limbs from four fresh feline cadavers to assess the ScN in three regions (glutea, femoralis and popliteal) using a 4-13MHz linear transducer. Five healthy adult experimental cats were employed for an 'in vivo' ultrasonographic study of the ScN using the same protocol described for the 'in vitro' study. The ultrasonographic images of the ScN were well correlated with those obtained in the anatomical study. The ScN was easily identified in all the approaches. The ScN was observed as a hypoechoic structure with internal echoes, outlined by hyperechoic lines. This study shows the usefulness of ultrasound to evaluate the entire pathology of the ScN in the cat.  相似文献   

4.
A study was designed to identify epidemiologic factors associated with the development and spread of salmonellae in horses in a veterinary teaching hospital, through a case-control study and a longitudinal follow-up prospective study. In the case-control study, 44 horses shedding salmonellae in feces were compared with 99 control horses not shedding salmonellae in feces; regarding breed, sex, age and initial diagnosis, none of the odds ratios for study factors was significant. The factors found to be associated with fecal shedding of salmonellae in the prospective study included diarrhea at the time of admission to the hospital, fever while hospitalized, and a change in diet while hospitalized. Horses identified to be shedding salmonellae in feces were not limited to those with clinical signs of salmonellosis; however, spread of salmonellae from a shedder without clinical signs of disease to other hospitalized horses was not identified. The most common serovars of Salmonella isolated were oranienburg and newport.  相似文献   

5.
The significance of collateral ligament desmitis of the tarsocrural joint is often clinically underestimated, because it is an uncommon injury with a guarded prognosis for athletic soundness. The objective of this study was to describe the clinical presentation, treatment, and outcome of 12 horses with collateral ligament desmitis, along with tarsocrural joint synovitis secondary to hemarthrosis. Criteria for inclusion in this study included clinical signs of tarsocrural joint synovitis and sonographic evidence of collateral ligament desmitis. This retrospective study evaluated horses over an 8-year period. Median follow-up after treatment was 5.5 years. Four horses in the study returned to their previous level of performance, 6 horses remained lame due to pain in the tarsus, 1 was euthanized, and 1 is in convalescence. This study highlights the importance of collateral ligament desmitis, and emphasizes the need for early, aggressive treatment to prevent the development of osteoarthritis.  相似文献   

6.
通过对某中学初中三个年级学生的问卷调查,为研究情感因素对初三英语学习的影响情况提供了数据依据,并发现了从初一到初三情感因素对初中英语学习的影响情况的变迁规律,总结出了影响初三英语学习的主要情感因素,提出了改进教学的建议思路。  相似文献   

7.
电子显微镜技术在肿瘤学研究中正发挥着重要作用。它使肿瘤病理学研究进入到了超微结构水平。本文分别探讨了透射电镜、扫描电镜及免疫电镜技术在肿瘤学中的临床应用、研究情况及其发展的前景与趋势。  相似文献   

8.
Endotracheal tubes manufactured from red rubber and polyvinyl chloride (PVC) were compared, using radiographic techniques, in dog cadavers, under in vitro conditions and in anaesthetised dogs (in vivo study). All endotracheal tubes were radiographed in 'neutral' and flexed positions and the percentage reduction in the ventrodorsal radiographical diameter of the tube was calculated. The red rubber tubes kinked completely in 40 per cent of the cadavers, 75 per cent of the in vitro study and 40 per cent of anaesthetised dogs. The PVC tubes kinked completely in only one case (in vivo study). However, these tubes had a mean reduction in diameter of 15 per cent in the dog cadaver study, 19 per cent in the in vitro study and 26 per cent in the in vivo study. During procedures in which the trachea is intubated and the atlanto-occipital joint of the patient must be flexed, PVC endotracheal tubes may be less prone to kinking than red rubber tubes.  相似文献   

9.
草地退化相关概念辨析   总被引:21,自引:0,他引:21  
草地退化是草地生态学和草地经营学中倍受关注的问题。在已有研究成果和笔者的研究体会的基础上总结了草地退化中的几组重要概念,包括生态退化与草场退化、植被退化与土壤退化、结构退化与功能退化、绝对退化与相对退化、参照系统与退化程度以及草地退化小尺度定位研究与大尺度空间格局研究,对其进行辨析,同时指出这些概念的划分在草地退化理论与实践研究中的重要意义。  相似文献   

10.
This study attempted to prove our hypothesis that a short-term toxicity study, using a 4-day dosing regimen as an example, is suitable for evaluating myelotoxicity in rats. We compared the hematological, bone marrow cytological and histopathological results of 5-fluorouracil (5-FU) treated and pair-feeding groups after a 4-day administration period. Several experimental groups were defined for this 4-day study as well as for our previously reported 14-day study (Miyata et al., 2009); these included 5-FU treated groups receiving 12, 15 and 18 mg/kg/day (FU12, FU15 and FU18), pair-feeding groups (R12, R15 and R18 receiving the same amount of food as the FU12, FU15 and FU18 groups, respectively) and a nontreated control group. Although severe reductions in body weight gain and food consumption were reported in the 14-day study, only slight reductions were observed in the 4-day study. In the 4-day study, a decrease in blood reticulocytes and a decreasing trend of marrow erythroid cells were only observed in the FU18 group, and no effects were observed in the pair-feeding groups. The erythroblastic changes observed in this 4-day study were thought to reflect the direct influence of 5-FU administration. Since concerns regarding the influence of secondary changes related to undernutrition were minimized in the 4-day study, it was thought to clarify the direct influence of 5-FU administration on erythroblastic cells. Thus, a 4-day study protocol might be helpful for distinguishing secondary changes related to undernutrition.  相似文献   

11.
Studies were carried out to determine the therapeutic efficacy of doramectin, administered intramuscularly at a dose of 300 microg/kg live weight, against naturally acquired helminths of extensively farmed Iberian pigs. The first study (slaughter study) evaluated, through necropsy of the study animals, the product's efficacy against gastrointestinal and pulmonary nematodes (Ascaris suum, Oesophagostomum dentatum and Metastrongylus sp.) whilst the second, faecal egg count reduction study, (FECR study) evaluated the drug's efficacy only against gastrointestinal helminths (A. suum, Trichuris suis and Oesophagostomum sp.).The first study used 20 animals divided into two equal groups of 10 on the basis of body weight and faecal egg count. One group constituted saline treated controls and the other was doramectin treated. On Day 14 post treatment half of the animals in each group were necropsied and the number of parasites present counted. On Day 15 the remaining half of each group underwent the same procedure. The second study was carried out with 40 animals divided equally into two groups of 20. This study determined the effect of doramectin treatment on faecal egg counts as an indicator of parasite burden.The first study demonstrated an efficacy of 100% against adult Metastrongylus sp. and A. suum, whilst the efficacy against O.dentatum was 96.3%. The second study indicated that at Day 21 post treatment there was a 100% reduction in egg counts in faeces in comparison to untreated controls.  相似文献   

12.
我国拥有丰富的牧草种质资源,但我国牧草种质资源的研究水平还比较低。通过对热带牧草种质资源收集、保存与创新利用进行了系统的概括和归纳,简要评述了我国牧草种质资源研究中存在的问题并展望其应用前景。以期为促进我国热带牧草种质资源的收集和利用提供参考。  相似文献   

13.
魏锡曾是清代晚期一位杰出的金石学家、书法理论家。道光以后,经过了阮元的号召和包世臣的推动,碑学理论逐步成熟.并大兴于咸、同年间。此时的书家少有超出碑学樊篱者,魏氏也不例外,其书学思想带有明显时代的烙印。然而,在其书论、题跋中,我们更能看出魏氏的书学思想植根于传统。文中对魏锡曾《绩语堂全集》中的书论、题跋进行梳理.总结出魏氏的书学思想主要有三:学篆、隶为存古法;以碑学技法求古法;不废传统帖学。  相似文献   

14.
试验通过在妊娠期和哺乳期的母羊日粮中添加不同水平酵母硒,研究不同水平母源硒对后代公羔睾丸发育的影响。结果表明:对照组羔羊的睾丸重量、长度和周径均为最低,而0.5 mg/kg组羔羊最高,随后随着日粮硒含量的增加,睾丸重量、长度和周径逐渐降低。H-E染色的结果表明,0.5mg/kg组睾丸的曲精细管管壁最厚,生精细胞数量最多,而2.0 mg/kg与4.0 mg/kg组羔羊睾丸的曲精细管管壁较薄,生精细胞数量相对较少,而且生精细胞之间有较大空隙。试验说明母体中的硒元素可以通过胎盘与乳汁转移给后代,影响后代公羔的睾丸发育。适宜的母源硒可以促进后代公羔的睾丸发育,而较高的硒添加量会对后代睾丸的发育造成不良影响。  相似文献   

15.
A study was designed to evaluate the representativeness and accuracy of data collected on swine birth defects by mailed questionnaire. The study was conducted in the three contiguous counties of Johnson, Lafayette and Pettis in west central Missouri. A personal interview survey and an examination of malformed pigs were used to validate mailed questionnaire data which estimated the frequency and distribution of malformations observed in pigs over a six month period. This period between April and September 1970 was defined as the study period. The results were compared to a previous six month period (April-September 1969), or baseline period, when only the mailed questionnaire was used. The frequency and distribution of the reported malformations by type did not differ significantly (at the p=0.05 level) between the study period (70.4% response) and the baseline period (31.3% response). Evaluation of this and additional data collected during the study suggested that the mailed questionnaire can be used effectively to estimate the frequency and distribution of swine malformations within a defined geographic area.  相似文献   

16.
Two studies were conducted to evaluate the factors associated with the development of thrombophlebitis in cattle following intravenous catheterization of the jugular vein. In study 1, 20 healthy animals were catheterized with 2 different types of catheter (polytetrafluoroethylene (PTE) versus polyvinylchloride (PVC)) for a period of 120 hours. In study 2, 50 dairy cows referred for treatment to the Large Animal Veterinary Teaching Hospital at the University of Montreal were catheterized with a commercial PTE catheter, using a standardized technique, for a period varying from 3 to 6 days, and inherent risk factors were evaluated. A clinical and echographical evaluation of the 2 groups in study 1 demonstrated a higher frequency of thrombosis in the PTE group than in the PVC group. In study 2, the primary factors associated with the development of thrombophlebitis in sick cows were the experience of the manipulator and the severity of the disease.  相似文献   

17.
A contrast radiographic study of the urinary and gastrointestinal system was carried out in 43 animals, with the aid of barium sulfate, orally for esophageal, stomach, small intestine and large intestine studies; barium sulfate as an enema to complete the large intestine studies; sodium and meglumine diatrizoate intravenously for urography and iodipamide meglumine intravenously for cholecystography. Both unanesthetized and anesthetized or tranquilized animals were used in the study. The results of the study are illustrated, and contrasted with studies of a similar nature in other animals.  相似文献   

18.
The intravenous pharmacokinetic profile of tilmicosin is yet to be achieved because of the cardiovascular effects of tilmicosin. This study summarizes two pharmacokinetic studies that provided complete pharmacokinetic profile of tilmicosin in cattle. The first study was a pharmacokinetic study of tilmicosin in beef calves dosed by i.v. infusion over 5 h. The second study was a subcutaneous (s.c.) pharmacokinetic study comparing the pharmacokinetic profile of tilmicosin in light (approximately 170 kg) and heavy (approximately 335 kg) beef cattle and comparing the labeled dose range of 10 or 20 mg/kg dose. The data from the two different studies were used to calculate bioavailability values, which support the assumption that tilmicosin is 100% bioavailable in cattle. The results from the second study showed that the weight of an animal when administered tilmicosin does not have a significant effect on exposure, but did demonstrate that doubling the dose of tilmicosin administered doubles the systemic exposure to tilmicosin.  相似文献   

19.
[目的]研究栓系饲养与散放饲养两种不同饲养方式对西门塔尔牛增重、生长和健康状况的影响.[方法]采用成组试验设计方法,进行栓系饲养与散放饲养两种饲养育肥方式对比;[结果]对照组初始重、育肥2个月体重、育肥2个月平均日增重、育肥3个月体重、育肥3个月平均日增重分别为473.68 kg,584.20 kg,1843.67 g...  相似文献   

20.
A study was undertaken to evaluate owners' perception of the effect that epilepsy and long-term phenobarbital therapy had on the quality of pet and owner lifestyle. Selected owners who participated in a prospective, longitudinal clinical epilepsy study were sent a questionnaire at the end of the two-year study. Inclusion criteria were dogs with a history of seizures without previous medical attention or therapy by any veterinarian before enrolment, subsequent determination of seizure aetiology using a standardised diagnostic protocol and treatment with phenobarbital for a minimum period of six months. A relatively equal distribution of the respondents' dogs had a determined (secondary, 47 per cent) or undetermined (primary, 53 per cent) seizure aetiology, and the vast majority of owners agreed that they would choose to treat their epileptic pet again rather than opt for other alternatives. Most owners disagreed that their pet was leading a poor quality of life after the start of phenobarbital therapy. A significant negative correlation existed between an owner's perception of the pet's quality of life and the amount of work required to care for the pet during the two-year study period. This study demonstrates that many owners are willing to care for epileptic dogs on long-term phenobarbital treatment, regardless of the underlying cause.  相似文献   

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