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971.
972.
The level of some enzymatic activities in red blood cells before and after photohemolysis induced by protoporphyrin IX was studied. A 30% decrease in catalase activity was found both in normal erythrocytes and those from patients affected by favism. Other proteins though present in larger amounts inside the erythrocytes are not affected by the photohemolytic process.  相似文献   
973.
974.
975.
Inhaled nitric oxide (NO) is used to treat various cardiopulmonary disorders associated with pulmonary hypertension. The rationale is based on the fact that NO, given by inhalation, only dilates those pulmonary vessels that perfuse well-ventilated lung units. As a result, pulmonary gas exchange is improved while pulmonary vascular resistance is reduced and pulmonary blood flow is increased. Inhaled NO has been succesfully applied to treat persistent pulmonary hypertension of the newborn, reducing the need for extracorporeal life support. Although pulmonary hypertension and altered vasoreactivity contribute to profound hypoxaemia in adult and paediatric acute respiratory distress syndrome (ARDS), the benefit of inhaled NO still remains to be established in patients with ARDS. ARDS is a complex response of the lung to direct or indirect insults, leading to pulmonary vasoconstriction and various inflammatory responses. Recent randomized trials suggest that inhaled NO only causes a transient improvement in oxygenation. Whether this effect is important in the long-term management of ARDS remains to be established. NO, measured in the exhaled breath, is an elegant and non-invasive means to monitor inflammation of the upper and lower respiratory tract. In the normal upper airways, the bulk of exhaled NO originates from the paranasal sinuses. Exhaled NO is increased in nasal allergy and decreased in cystic fibrosis, nasal polyposis and chronic sinusitis. That NO production is increased in asthmatic airways is also well established. However, several questions still need to be addressed, in particular evaluation of the sensitivity and specificity of the measurement techniques, and assessment of the bronchodilator action of endogenous NO.  相似文献   
976.
用柱层析和TLC分离小麦PGIP和植保素   总被引:1,自引:0,他引:1  
植物抗病能力大小的测定需要比较准确可靠且相对简便的办法。采用接种病菌于植物上观察染菌情况虽然直观,但受病菌本身的生理状态及外界环境影响很大,且不便于定量的表述。因此,选择合适的生理生化指标作为植物抗性大小的衡量标准,对于植物病理的研究具有重要的意义。选择了小麦体系的两种抗性物质- 小麦植保素和 P G I P作为小麦的抗性指标来分离分析  相似文献   
977.
Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Peromyscus maniculatus and related small rodents have been examined for ectoparasites in the tundra region of the Rocky Mountain National Park 1974–1979. One hundred and ninety-four P. maniculatus were examined from two tundra sites. Flea infestation rates were 1.9 fleas per mouse examined and 4.1 fleas per infested mouse. Species taken in significant numbers were Monopsyllus thambus (51 percent), Peromyscopsylla hesperomys (34 percent), Malaraeus euphorbi (9 percent), and Catallagia calisheri (4 percent). Peromyscus maniculatus host/flea relationships in the tundra are compared with those in other life zones in the park.    相似文献   
978.
Nuclear transport mechanisms   总被引:7,自引:0,他引:7  
The term nuclear transport, refers to the movement of a large variety of macromolecules both into and out of the nucleus. Transport must be extremely selective, yet also very efficient. A single type of channel, the nuclear pore complex, mediates all movement across the nuclear envelope. Selectivity is achieved through the use of families of soluble factors that target substrates for import and export and deliver them to their appropriate intracellular destinations. We now have a fairly detailed understanding of the basic mechanisms of protein import into the nucleus. Many of these same principles can be applied to protein export and perhaps RNA export. This review will summarize the current status of what is known about various transport pathways and highlight the questions that remain to be answered.  相似文献   
979.
Species diversity, niche metrics, cover, frequency, and soil relationships were studied on high mountain meadows on adjacent cattle and sheep allotments in Strawberry Valley, Wasatch County, Utah. The cattle allotment vegetation was predominantly Mountain bluebell (Mertensia ciliata) , and the sheep allotment vegetation was predominantly Smallwing sedge (Carex microptera) . Other species of importance on both areas included Letterman needlegrass (Stipa lettermanii) , Mountain bromegrass (Bromus carinatus) , and Yarrow (Achillea millefolium) . Tall forbs were most abundant on the cattle allotment, and low forbs, perennial grasses, and sedges were most abundant on the sheep allotment. Vegetation composition on the two allotments was significantly different.      相似文献   
980.
An inventory of the terrestrial vertebrate fauna and the seasonal occurrence of each species was determined for a man - made radioactive leaching pond complex in southeastern Idaho. Three reptile, 11 mammal, and 94 bird species were identified from February 1974 through January 1978. Fewest species were observed during the winter and most during the summer. Eight bird species nested at the pond complex, while 19 species of birds were common or seasonally abundant. It appears that the Test Reactor Area radioactive leaching pond complex is an important water source and provides habitat for some species of wildlife.  相似文献   
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