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 31 毫秒
1.
Freeze-dried platelets promote hepatocyte proliferation in mice   总被引:1,自引:0,他引:1  
In recent years, platelets are reported to promote liver, as well as bone regeneration and dermal wound healing. Platelets are required not only for thrombocytopenia treating but also for regenerative therapy. Platelets cannot be stored beyond three days, therefore, shortage of fresh platelets sometimes occurs. To preserve platelets for a long duration without degrading growth factors, a freeze-dried technique is required. We report here that platelets can be preserved by freeze-drying, using a programmed freezing method to avoid intracellular ice crystal formation. Freeze-dried platelets kept their morphological countenance and response with the agonist of thrombin was well maintained. Freeze-dried platelets stored adenine nucleotides, PDGF, and IGF-1 the same as those of fresh platelets. Freeze dried platelets also preserved their proliferative effect on hepatocytes identical to that of fresh platelets. These results of our study suggest that freeze dried platelets will obviate the storage problem of fresh platelets.  相似文献   

2.
《Cryobiology》2008,56(3):255-260
In recent years, platelets are reported to promote liver, as well as bone regeneration and dermal wound healing. Platelets are required not only for thrombocytopenia treating but also for regenerative therapy. Platelets cannot be stored beyond three days, therefore, shortage of fresh platelets sometimes occurs. To preserve platelets for a long duration without degrading growth factors, a freeze-dried technique is required. We report here that platelets can be preserved by freeze-drying, using a programmed freezing method to avoid intracellular ice crystal formation. Freeze-dried platelets kept their morphological countenance and response with the agonist of thrombin was well maintained. Freeze-dried platelets stored adenine nucleotides, PDGF, and IGF-1 the same as those of fresh platelets. Freeze dried platelets also preserved their proliferative effect on hepatocytes identical to that of fresh platelets. These results of our study suggest that freeze dried platelets will obviate the storage problem of fresh platelets.  相似文献   

3.
There will be a need for a wide array of chemical sensors for biomedical experimentation and for the monitoring of water and air recycling processes on Space Station Freedom. The infrequent logistics flights of the Space Shuttle will necessitate onboard analysis. The advantages of biosensors and chemical sensors over conventional analysis onboard spacecraft are manifold. They require less crew time, space, and power. Sample treatment is not needed. Real time or near-real time monitoring is possible, in some cases on a continuous basis. Sensor signals in digitized form can be transmitted to the ground. Types and requirements for chemical sensors to be used in biomedical experimentation and monitoring of water recycling during long-term space missions are discussed.  相似文献   

4.
The effects of low temperature storage on the physiology of cut rose flowers ( Rosa hybridaL. cv. Mercedes) were studied. Extension of cold storage or increase in temperature (from 3 to 8°C) was accompanied by shortening of vase life and advancement of petal senescence, as reflected in an advance in the timing of the rise in ethylene production and an increase in membrane permeability (ion leakage). Although storage at a relative humidity (RH) of 65% reduced petal water content by 20% in comparison with flowers stored at 95% RH, it did not shorten vase life. The progression of petal senescence was measured during storage at 3°C and during aging at 22°C. Both ethylene production rates and membrane microviscosity measured by fluorescence depolarization increased with time at 3°C and at 22°C, but more slowly at 3°C. At 3°C membrane permeability measured by ion leakage did not increase. Following cold storage the rate of ethylene production in the petals was increased by up to eight times the rate in unstored flowers. Silver thiosulphate extended the vase life of both stored and fresh flowers equally by 2 days, but did not increase the life of stored flowers to that of treated fresh flowers. It is concluded that the primary effect of cold storage on roses is to slow down senescence and that the continued slow senescence leads to shorter vase life. The possible occurrence of sequential processes during senescence and the effects of temperature on these processes is discussed.  相似文献   

5.
The second annual meeting of the NSCORT in Gravitational Biology was held at Kansas State University on September 29-October 1, 1992. Symposium presentations at the meeting included ones on basic gravitational cellular and developmental biology, spaceflight hardware for biological studies, studies on Space Shuttle, and special talks on Space Station Freedom and on life support systems.  相似文献   

6.
Lipid Storage and Utilization in Reptiles   总被引:5,自引:0,他引:5  
Lipids represent a biochemically efficient mechanism for storingenergy to be used at a later date for maintenance and/or reproduction.This storage and utilization at different times results in seasonalpatterns of lipid cycling. Reptiles exhibit a number of lipidcycling patterns which can be explained by seasonal patternsof food availability. Seasonality in food availability determinesthe quantity of lipids stored, when lipids are stored, and forwhat purposes these lipids are utilized. Lipid cycling patternsare in turn correlated with life histories.  相似文献   

7.
Aims: The aim of the study was to evaluate the behaviour of Listeria monocytogenes in the conditioning liquid of packaged water buffalo mozzarella cheese (WBMC). Methods and Results: The conditioning liquid was contaminated with L. monocytogenes, and the contaminated samples were stored at four different storage temperatures: 5 and 10°C for 22 days; 20°C for 9 days; 20°C for 3 days and then at 5°C for 6 days. The results showed that L. monocytogenes concentration decreased when contaminated samples were stored at 5°C. When WBMC was stored at 20°C and at 10°C, L. monocytogenes started to grow after a lag phase of 3 and 10 days, respectively. When samples were stored at variable temperature conditions, L. monocytogenes numbers showed a lag phase of 5 days. Conclusions: Use of a conditioning liquid characterized by acidity and a correct storage temperature is able to counteract pathogen replication during shelf life. A high concentration of lactic acid bacteria was associated with effective control of L. monocytogenes but the role of lactic acid bacteria in WBMC conditioning liquid requires further investigation. Significance and Impact of the Study: According to European regulations, food producers should be able to justify decision‐making on the shelf life assigned to their products, taking into account reasonable storage conditions and use by consumers. The results of the trial yielded information for producers of WBMC and similar cheeses for decision‐making on product shelf life.  相似文献   

8.
水分胁迫对澳洲坚果花粉生活力和贮藏性的影响   总被引:7,自引:0,他引:7  
采集经不同水分胁迫处理的澳洲坚果植株的花粉进行生活力测定和贮藏性研究,结果表明,新鲜花粉生活力随贮藏时间增加而下降。常温下正常发育花粉可保存6d左右,此后萌发率逐渐下降;而处于水分胁迫下的花粉,6d后生活力迅速降低;水分胁迫程度越严重,花粉生活力下降越快。几种处理的花粉有效贮藏期分别是:饱和灌溉处理6d,正常灌溉处理30d,水分亏缺处理10d,严重干旱处理(CK)4d。研究还表明,品种间花粉贮藏性表现为Kau >Pahala >O.C.。澳洲坚果花粉生活力的最佳染色鉴定方法为联苯胺染色法。  相似文献   

9.
Mitsubishi Heavy Industries (MHI) and Japan Aerospace Exploration Agency (JAXA) have been studying Aquatic Animal Experiment Facility, Aquatic Habitat (AQH), for International Space Station (ISS). The AQH will have the capabilities to accommodate small freshwater fish and amphibian for maximum 90 days on orbit. Three-generations of small freshwater fish (medaka and zebrafish), and egg through metamorphosis of amphibian (African clawed toad) could be experimented by AQH. Various experimental functions such as automatic feeding, air-water interface, day/night cycle, video observation, and specimen sampling mechanism will be also equipped in AQH. The water circulation system was improved from the past aquatic facilities for Space Shuttle experiments under the consideration of the long life-time, and a brand-new specimen chamber was developed to equip the above various experimental functions. Currently the prototype model of water circulation system and specimen chambers have been manufactured and biological compatibility tests are being conducted with medaka. The current developmental status of AQH is summarized.  相似文献   

10.
In the present investigation the storage effect of AcD-AG and CPD-AG-stabilizers on thrombocytes was tested. The platelets were stored in platelet-rich plasma (PRP) at 4 degrees C or room temperature for 3 days. The concentrates gained by it were marked with Na251CrO4 and reinjected. The thrombocytokinetic parameters were evaluated. The results show that storage with the help of the mentioned stabilizers can be made to a certain extent only. Platelets stored in AcD-AG stabilizerhad a survival time of 2.7 +/- 1.1 days towards 9.0 +/- 1.0 days of fresh whole blood concentrates. The survival time of CPD-AG thrombocytes stored at 4 degrees C for 3 days amounted to 2.0 +/- 0.5 days. Storage of CPD-AG platelets at room temperature showed favourable results. Their survival time amounted to 6.2 +/- 0.6 days. Measurements of surface activity above the spleen and the liver indicate that degradation of stored platelets is mainly performed in the spleen. Problems of liquids storing in view of the significance of therapeutic thrombocyte substitution for hospitals are referred to.  相似文献   

11.
Xylem sap was collected from wheat and barley growing in a drying soil, and the effect of the sap on transpiration was detected by a bioassay with detached wheat leaves. The inhibitory activity of fresh sap was small, and could be largely accounted for by the abscisic acid content (about 2×10-5mol m-3). When fresh sap was stored at -20°C for several days, the activity increased. Maximum activity developed after a week. This increase in activity was due to a compound that increased in size with storage at -20°C. When fresh sap was fractionated with filters of different molecular size exclusion characteristics, and the separated fractions stored at -20°C for a week, activity developed only in the fraction containing compounds smaller than 0·3 kDa. However, when sap already stored at -20°C was fractionated, activity was only in fractions containing compounds larger than 0·3 kDa. The increase in activity and in size did not occur with storage in liquid nitrogen (-196°C) or at -80°C. These results suggest that storage at -20°C causes the aggregation or polymerization of a small compound with low activity to form a large compound with high activity. This change is not catalysed by an enzyme because it can occur in a fraction from which molecules larger than 0·3 kDa are removed. It is probably promoted by high solute concentrations when ice crystals form. Sap collected from plants in soils of high water potential had little or no activity after storage at -20°C.  相似文献   

12.
An enclosed ecosystem which is stable on Earth will behave differently when brought into space. Micro-gravity and radiation will affect the dynamics of material circulation or the activities of small creatures of the ecosystem. One series of space experiments aiming to address such issues was planned in the United States (It is termed as ABS--Autonomous Biological System) and Japanese group has been involved with cooperating with the analysis of the flight samples. Before the ecosystem will be on board Russian Space Station "Mir" later 1996 for 3 months, a preliminary flight was carried out in May 1996 on Space Shuttle (STS-77) for 10 days flight. It was the first of such experiments to fly one whole ecosystem in space.  相似文献   

13.
Dark reversion of the far red-absorbing form of phytochrome, which does not occur in dry lettuce (Lactuca sativa var. Grand Rapids) seeds, appears to take place in seeds stored in a water-saturated atmosphere. The water content (approximately 70% after 10 days) of such seeds is insufficient to support germination; however the treatment enhances germination in seeds stored for 1 to 5 days, but this enhancement subsequently disappears, and the effect of extended storage (up to 28 days) is inhibiting. The half-time for dark far red-absorbing phytochrome reversion is 7 to 8 days, and at this time it can be completely reversed by exposing the seeds to a flash of red light. Storage of more than 7 to 8 days decreases red light enhancement of germination.  相似文献   

14.
In the present investigations the storage effect the AcD-AG stabilizer on thrombocytes is examined. The thrombocytokinetic parameters of 9 fresh blood concentrates and 15 concentrates of AcD-AG plasma containing platelets were determined. Storage time amounted to three days. The results show that storage with AcD-AG is only possible to a limited degree. On an average the survival time of the platelets was reduced to 2.7 +/- 1.1 days compared with 9.0 +/- 1.0 days of fresh blood concentrates. The recovery of the stored platelets amounted to 25.3 +/- 16.1%, that of the fresh blood concentrates to 63.3 +/- 23.6%. The spleen-heart quotients and those of the liver-heart or the surplus impulses over the spleen and liver respectively indicate that there is a predominant destruction in the spleen for those thrombocytes stored for three days. The liver is scarcely involved in this sequestration process. With 36.1% platelet yield was very low in concentrates gained from AcD-AG plasma containing platelets and having been stored for 3 days. In cases of emergency a clinical application of concentrates prepared in this way should not be given up. If being used, the greater requirement has to be taken into account. If the substitution therapy is continued, however, fresh blood concentrates have to be used as soon as possible.  相似文献   

15.
Retrieval of stored seeds by Marsh Tits Parus palustris in the field   总被引:1,自引:0,他引:1  
T. A. STEVENS  J. R. KREBS 《Ibis》1986,128(4):513-525
The retrieval of stored food by Marsh Tits was documented using Hall-plate detectors to register visits to storage sites by marked individuals. In each experimental session a marked bird was allowed to store up to 50 radioactively labelled half-peanuts. By placing detectors next to each stored item that we located it was possible to show that birds attempt to retrieve about 25% of their stored food. Most of the retrieval is within one or two days (confirming Cowie et al. 1981) and the proportion of recorded retrieval attempts that are successful declines to zero after about three days. By this time storage sites have already been emptied by cache robbers. There may be a tendency for retrieval to occur in the afternoon.  相似文献   

16.
土壤氮素形态及含量具有重要的生态学研究意义,而土壤样品的储存对土壤氮素含量的准确测定有很大影响.为了选择合理的土壤样品储存方法,本研究以福建省建瓯市万木林保护区罗浮栲林土壤为研究对象,测定在不同温度(25、4和-20 ℃)、不同储存时间(0、7和30 d)下土壤铵态氮、硝态氮、总氮、可溶性有机氮、氨基酸氮含量和微生物生物量氮,以及冷冻后常温培养过程中的氮素含量.结果表明: 在7 d的储存时间内,除氨基酸氮以外,常温培养样品下其余的氮素含量均有所增加;与新鲜样品相比,冷藏、冷冻样品的所有氮素含量之间均无显著性差异,且氮素含量变化较常温培养下更加稳定.因低温储存样品有刺激氮矿化的效果,在30 d储存时间内,与新鲜样品相比,除可溶性有机氮外,冷藏、冷冻样品的所有氮素含量均显著升高;两种冷储存方法之间无显著差异.因此,新鲜样品带回实验室后应及时处理;如需要冷储藏,时间不要超过半个月.如果需要较长的储存时间,则需将样品放置于更低的温度(-40或-80 ℃).在对储存土壤样品进行培养试验之前,需要进行预培养处理.在预培养过程中,除硝态氮含量呈现先下降再迅速升高的趋势外,其余氮素均随着培养时间逐渐趋近于新鲜土壤样品含量,在培养一周左右恢复到与新鲜土壤样品氮含量最为接近的状态.结合已有研究,对野外取样和风干样品需要5~14 d的预培养,冷储存样品预培养时间不应少于一周.  相似文献   

17.
Fat, Energy and Mammalian Survival   总被引:2,自引:0,他引:2  
Adipose tissue plays a critical role in mammalian life historystrategies, serving as an organ for the storage of food andenergy, as a source of heat and water and as thermal insulation.The food and energy storage roles are especially important inallowing the animals to survive food shortages and stressesassociated with competition for mates, territorial defense,gestation and lactation, and to accomplish migrations. The composition,cellularity and anatomical site of adipose depots in a mammalcan influence both the amount of fat stored and its availabilityand usefulness in any given situation. The fatty acids and complexlipids in adipose tissue, blood vessels, nerves and brain changein response to ambient temperature and the low body temperaturesduring hibernation. Early nutrition may influence the numberof fat cells developed by a mammal, and thus affect its abilityto survive adversity. Desert species develop localized depotswhich will not interfere with temperature regulation, whileanimals in cold environments use their extensive superficialfat layers as insulation.  相似文献   

18.
Millions of blood products are transfused each year, and many lives are directly affected by transfusion. Platelet concentrate (PC) is one of the main products derived from blood. Even under good storage conditions, PC is likely to suffer cell damage. The shape of platelets changes after 5 to 7 days of storage at 22°C. Taking into consideration that some platelet proteins undergo changes in their shape and functionality during PC storage. Sixteen PC bags were collected and each PC bag tube was cut into six equal pieces to perform experiments with platelets from six different days of storage. Thus, on the first day of storage, 1/6 of the tube was used for miRNA extraction, and the remaining 5/6 was stored under the same conditions until extraction of miRNAs on each the following five days. Samples were sequenced on an Illumina Platform to demonstrate the most highly expressed miRNAs. Three miRNAs, mir127, mir191 and mir320a were validated by real-time quantitative PCR (RQ-PCR) in 100 PC bags tubes. Our method suggests, the use of the miRNAs mir127 and mir320a as biomarkers to assess the "validity period" of PC bags stored in blood banks for long periods. Thus, bags can be tested on the 5th day of storage for the relative expression levels of mir127 and mir320a. Thus, we highlight candidate miRNAs as biomarkers of storage damage that can be used as tools to evaluate the quality of stored PC. The use of miRNAs as biomarkers of damage is unprecedented and will contribute to improved quality of blood products for transfusions.  相似文献   

19.
Plants in space     
Virtually all scenarios for the long-term habitation of spacecraft and other extraterrestrial structures involve plants as important parts of the contained environment that would support humans. Recent experiments have identified several effects of spaceflight on plants that will need to be more fully understood before plant-based life support can become a reality. The International Space Station (ISS) is the focus for the newest phase of space-based research, which should solve some of the mysteries of how spaceflight affects plant growth. Research carried out on the ISS and in the proposed terrestrial facility for Advanced Life Support testing will bring the requirements for establishing extraterrestrial plant-based life support systems into clearer focus.  相似文献   

20.
Wang  Chaozi  Wu  Lingling  Zhang  Yue  Xu  Minmin  Saldaña  Marleny D. A.  Fan  Xiaoli  Sun  Wenxiu 《Food biophysics》2022,17(3):437-447

To extend the shelf life of cold fresh mutton, the water-absorbent antibacterial mat was developed. This mat was composed of polylactic acid-β-cyclodextrin/eugenol (PLA-β-CD/EUG) fiber membrane, super absorbent polymer (SAP) and filter paper, in which the fiber membrane was developed by the electrospinning technique. The β-CD/EUG inclusion complexes were shown to form successfully by scanning electron microscope (SEM), fourier transform infrared spectroscopy (FTIR), water contact angle (WCA) analysis. The release experiment indicated that the PLA-β-CD/EUG fiber membranes had a slow-release effect, especially in the fatty food simulant. The water-absorbent antibacterial mats can restrain the growth of six spoilage bacteria. The mats were evaluated for the preservation of cold fresh mutton. The results revealed that it displayed prolongation of shelf life upon 8 days during the mutton at 4 °C storage period. The water-absorbent antibacterial mat can slowly release natural antibacterial agents and absorb water to achieve preservation, suggesting a potential application in meat products.

  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