首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
Patients with allergic diseases of the skin and the respiratory system were found to have a high rate of disturbances in the microbial ecology of the gastrointestinal tract and the involvement of all its sections into the pathological process. On the mucous membrane of different sections of the digestive tract spiral-like bacteria were detected in a large percentage of cases. The possibility of the fact that the development and maintenance of the allergic process were evidently linked with the detected changes in the microbial ecology and pathomorphological features of the gastrointestinal mucosa could hardly be excluded, which made it necessary to make corrections in the therapeutic process.  相似文献   

3.
Cyclooxygenase (COX) inhibition during allergic sensitization and allergen airway challenge results in augmented allergic inflammation. We hypothesized that this increase in allergic inflammation was dependent on increased generation of leukotrienes that results from COX inhibition, as leukotrienes are important proinflammatory mediators of allergic disease. To test this hypothesis, we allergically sensitized and challenged mice deficient in 5-lipoxygenase (5-LO). We found that 5-LO knockout mice that were treated with a COX inhibitor during allergic sensitization and challenge had significantly increased airway hyperresponsiveness (AHR) (p < 0.01) and airway eosinophilia (p < 0.01) compared with 5-LO knockout mice that were treated with vehicle. The proinflammatory cytokines have also been hypothesized to be critical regulators of airway inflammation and AHR. We found that the increase in airway eosinophilia seen with COX inhibition is dependent on IL-5, whereas the increase in AHR is not dependent on this cytokine. In contrast, the COX inhibition-mediated increase in AHR is dependent on IL-13, but airway eosinophilia is not. These results elucidate the pathways by which COX inhibition exerts a critical effect of the pulmonary allergen-induced inflammatory response and confirm that COX products are important regulators of allergic inflammation.  相似文献   

4.
Abstract Numerous bacteria present in soil during its passage through the alimentary canal of earthworms resist digestive action and the antimicrobial defenses of the worms. Thus, several kinds of non-sulfur purple photosynthetic bacteria (Rhodospirillaceae) can be enriched from 'purees' of washed earthworms (or from intestinal contents of the worms) using a procedure that exploits the capacity to fix N2 during anaerobic phototrophic growth with organic acid carbon sources. It appears that earthworm enrichments can be designed to provide highly selective methods for isolation of Rhodomicrobium vannielli and Rhodopseudomonas palustris , and perhaps of other purple bacteria. The extensive burrowing activities of earthworms undoubtedly contributes to the widespread dissemination of Rhodospirillaceae in soils.  相似文献   

5.
养殖动物消化道中含有大量的微生物,不仅参与动物对营养物质的消化和吸收,还对宿主生长发育及免疫起重要调节作用。动物消化道微生物组研究是目前国内外的热点领域,取得了一系列重要研究进展。深入了解养殖动物消化道微生物组的结构与功能,将为今后调控和应用消化道微生物、提高动物生产性能、改善动物胃肠道健康和实现绿色健康养殖奠定理论基础。本文以4种代表性养殖动物(牛、羊、猪和鸡)为主体,对组学视角下其消化道微生物群落结构、功能等研究进展进行总结和分析;并对未来研究方向进行展望。  相似文献   

6.
The functional link between food as an energy source and metabolizable energy is the digestive tract. The digestive organs may change in size, structure, or retention time in response to energetic demands of the animal. Very efficient digestive tracts may be better at processing food but require higher energetic investments for maintenance even when post-absorptive. These costs influence the resting metabolic rate (RMR) that is defined as the energy necessary to fuel vital metabolic functions in a resting animal. In bats a trade-off between the necessity for a highly efficient digestive tract and moderate energetic maintenance costs may be particularly important. We hypothesized that low RMR coincides with low digestive efficiency (defined as apparent metabolizable energy coefficient (MEC)) and that phases of increased energetic demand are compensated for by increased digestive efficiency. We measured RMR and apparent MEC in the bats species Myotis nattereri, M. bechsteinii, and Plecotus auritus. In support of our hypothesis, M. nattereri has the lowest mass-specific RMR of the three species and the lowest apparent MEC. However, apparent MEC did not change during phases with differing energetic demands in any of the bat species, probably because bats operate at the limit of their sustainable energy demand.  相似文献   

7.
In rabbits, the bacterial and archaeal community of caecal ecosystem is composed mostly of species not yet described and very specific to that species. In mammals, the digestive ecosystem plays important physiological roles: hydrolysis and fermentation of nutrients, immune system regulation, angiogenesis, gut development and acting as a barrier against pathogens. Understanding the functioning of the digestive ecosystem and how to control its functional and specific diversity is a priority, as this could provide new strategies to improve the resistance of the young rabbit to digestive disorders and improve feed efficiency. This review first recalls some facts about the specificity of rabbit digestive microbiota composition in the main fermentation compartment, and its variability with some new insights based on recent molecular approaches. The main functions of the digestive microbiota will then be explained. Finally, some possible ways to control rabbit caecal microbiota will be proposed and a suitable timing for action will be defined.  相似文献   

8.
Nowadays, safety and quality assessment of food used for human consumption have to consider by its possible contribution to the maintenance or improvement of the consumer''s health. Milk is an important food with many nutrients. Cow milk is an important source of energy, protein, vitamins and minerals for the growing child as well as adults. But, numerous cow milk proteins have been implicated in allergic responses and most of these have been shown to contain multiple allergic epitopes. The present study disclosed best alternatives to cow milk, which are not allergic and as good as cow milk in nutritional value. The in silico analysis of casein (alpha s1, alpha s2, beta and kappa) and beta-lactoglobulin, unveils that sheep milk is a more suitable alternate to cow milk for allergic infants and buffalo milk for allergic adult humans.  相似文献   

9.
Allergic diseases result in a considerable socioeconomic burden. The incidence of allergic diseases, notably allergic asthma, has risen to high levels for reasons that are not entirely understood. With an increasing knowledge of underlying mechanisms, there is now more potential to target the inflammatory process rather than the overt symptoms. This focuses attention on the role of leukocytes especially Th2 lymphocytes that regulate allergic inflammation and effector cells where eosinophils have received much attention. Eosinophils are thought to be important based on the high numbers that are recruited to sites of allergic inflammation and the potential of these cells to effect both tissue injury and remodelling. It is hoped that future therapy will be directed towards specific leukocyte types, without overtly compromising essential host defence responses. One obvious target is leukocyte recruitment. This necessitates a detailed understanding of underlying mechanisms, particularly those involving soluble chemoattractants signals and cell-cell adhesion molecules.  相似文献   

10.
11.
T. R. Ricketts 《Protoplasma》1971,73(3-4):387-396
Summary Starved cells ofTetrahymena pyriformis show marked periodicity in the rates of uptake of digestive vacuoles when presented with a mixture of peptone and polystyrene latex particles. Rates of egestion also show some periodicity. The results show that the supply of membrane is not the sole factor (and possibly not even a main factor) restricting vacuolar uptake. The rates of egestion also do not appear to be greatly influenced by the amounts of digestive vacuole membrane to be reincorporated into the cell membrane. It is suggested that energy and lysosomal supplies may be more important than membrane supply for uptake and that reduction in the supply of uncombined lysosomes may in some way cause cessation of vacuole formation.Fed cells ofTetrahymena also show variations in the rate of digestive vacuolar uptake with time. The maximum rate of uptake is about three times as great as that found in starved cells.  相似文献   

12.
Peroxisome proliferator-activated receptors (PPARs) play very important roles in various biological phenomena such as regulation of lipid metabolism, homeostasis, cell differentiation and proliferation, in a variety of organs and tissues. However, their functions in the development of the digestive organs have not been studied yet, although it has been supposed that they are involved in the tumor development and regression of digestive organs. To provide fundamental data to analyze functions of PPARs in the developing digestive organs in the chicken embryos, we performed thorough analysis of expression of PPARalpha, beta (delta) and gamma in the esophagus, proventriculus (glandular stomach), gizzard (muscular stomach), small and large intestines from early developmental stages to post hatch stages. The results showed that each PPAR is expressed in spatio-temporally regulated manner. In general, PPARbeta is widely expressed among digestive organs whereas PPARalpha and gamma showed restricted expression. In the intestine, all PPARs are expressed after hatch, indicating that they play important roles in the physiology of the adult intestine.  相似文献   

13.
14.
This study was undertaken to examine the possibility that IgE is not the only immunoglobulin responsible for immediate allergic reactions. A group of asthmatics were investigated in whom immediate allergic reactivity of the bronchi to common inhalant allergens had been confirmed by provocation tests. Their sera were fractionated and the reaginic activity of the immunoglobulin classes was studied by passive cutaneous anaphylaxis testing in monkeys. The results showed that the immediate allergic reactions were due to IgE antibodies in most patients, but there was a group with reactions due to short-term anaphylactic IgG antibodies. It was not possible to inhibit the IgG-mediated responses with disodium cromoglycate. As these two groups had clearly different serum IgE levels the estimation of IgE provided an important guide to the management of these patients.  相似文献   

15.
Digestion in insects is a multi-step process to afford nutritional requirements of biological activities. The process starts with nervous stimuli and continues with biochemical activities of digestive enzymes as well as several pumps to digest and absorb the obtained molecules. Carbohydrases, lipases and proteases are the three main digestive enzymes involved in digestion process. Lipases seem to be very important not only for digestive role but also for esteratic activity so that some experts consider lipases as the Class 3 of general esterases. Digestive lipases divided into different groups based on their biological roles namely triacylglycerol lipases, phospholipases and two types of phosphatases. Briefly, triacylglycerol lipases (TAG-lipases) are the hydrolysing enzymes that affect the outer esteric links of triacylglycerols in ingested food. Phospholipases including PLA2 and PLA1 remove phosphatide fatty acids attached to the Position 2 and Position 1. Finally, Alkaline and acid phosphatases are the enzymes that hydrolyse phosphomonoesters under alkaline or acid conditions, respectively. In this review, presence and physiological role of digestive TAG-lipases are explained and their possible importance will be discussed in insect.  相似文献   

16.
哺乳动物的消化策略(英文)   总被引:13,自引:2,他引:11  
IanD.Hume 《动物学报》2002,48(1):1-19
理解动物的营养生态位是充分理解其整个生态学的基础,对于害兽控制和物种保护也很重要,食肉动物的小肠很发达,这可能与对食物的高消化能力有关;杂食性动物有更复杂的胃肠器官,其后端有可进行发酵的盲肠,消化物的平均滞留时间(mean retention times,MRTs)更长;最长的平均滞留时间见于食草动物,其消化道内高密度的微生物种群对不同滞留区内的消化物进行发酵,但是,并不是所有的食草动物都能够最大程度地消化植物纤维,只有反刍动物、骆驼和个体较大的后肠发酵动物(hindgut fermenter)能够具有这种能力,对比而言,许多其它的食草动物,如前肠发酵的有袋类和小型的后肠发酵动物如兔子、田鼠和负鼠等,它们具备可以使植物纤维消化效率最大的消化系统,可以在食物中的纤维素含量非常高的情况下仍能处理大量的食物。这些不同的消化策略使哺乳动物具有广幅的营养生态位。  相似文献   

17.
The presence of infection in allergic disease produces a confused picture in which two different causative factors must be clearly separated by the physician if he is to treat the patient successfully. The effects of infection are not consistent. There are situations, as seen in infectious diseases, where symptoms of allergic disease are temporarily relieved and others where the infection may intensify or precipitate the allergic condition. It is likewise important to recognize the complications superimposed upon allergic disease by infection. In such cases, control of the infection is as dependent upon control of the allergy as it is upon antibiotics.  相似文献   

18.
The presence of infection in allergic disease produces a confused picture in which two different causative factors must be clearly separated by the physician if he is to treat the patient successfully. The effects of infection are not consistent. There are situations, as seen in infectious diseases, where symptoms of allergic disease are temporarily relieved and others where the infection may intensify or precipitate the allergic condition. It is likewise important to recognize the complications superimposed upon allergic disease by infection. In such cases, control of the infection is as dependent upon control of the allergy as it is upon antibiotics.  相似文献   

19.
Digestive enzyme activity is often used as a sensitive response to environmental pollution. However, only little is known about the negative effects of stress on digestive capacities and their consequences on energy reserves and reproduction, although these parameters are important for the maintenance of populations. To highlight if changes in biochemical responses (digestive enzymes and reserves) led to impairments at an individual level (fertility), Gammarus fossarum were submitted to a lower food intake throughout a complete female reproductive cycle (i.e. from ovogenesis to offspring production). For both males and females, amylase activity was inhibited by the diet stress, whereas trypsin activity was not influenced. These results underline similar sensitivity of males and females concerning their digestive capacity. Energy reserves decreased with food starvation in females, and remained stable in males. The number of embryos per female decreased with food starvation. Lower digestive activity in males and females therefore appears as an early response. These results underline the ecological relevance of digestive markers, as they make it possible to anticipate upcoming consequences on reproduction in females, a key biological variable for population dynamics.  相似文献   

20.
The avian digestive system, like other aspects of avian biology, is highly modified relative to other reptiles. Together these modifications have imparted the great success of Neornithes, the most diverse clade of amniotes alive today. It is important to understand when and how aspects of the modern avian digestive system evolved among neornithine ancestors in order to elucidate the evolutionary success of this important clade and to understand the biology of stem birds and their closest dinosaurian relatives: Mesozoic Paraves. Although direct preservation of the soft tissue of the digestive system has not yet been reported, ingested remains and their anatomical location preserved in articulated fossils hint at the structure of the digestive system and its abilities. Almost all data concerning direct evidence of diet in Paraves comes from either the Upper Jurassic Yanliao Biota or the Lower Cretaceous Jehol Biota, both of which are known from deposits in north-eastern China. Here, the sum of the data gleaned from the thousands of exceptionally well-preserved fossils of paravians is interpreted with regards to the structure and evolution of the highly modified avian digestive system and feeding apparatus. This information suggests intrinsic differences between closely related stem lineages implying either strong homoplasy or that diet in each lineage of non-ornithuromorph birds was highly specialized. Regardless, modern digestive capabilities appear to be limited to the Ornithuromorpha, although the complete set of derived feeding related characters is restricted to the Neornithes.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号