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1.
Meana A Martinez R Cañal P Arriaga MJ Román FS Llames S Orós C Moreno A Fernandez C 《Cell and tissue banking》2006,7(3):203-206
In order to transport and cryopreserve human tissues, it is essential to have an easy-to-use recipient where tissues can be
kept in sterile conditions. Here we show the results obtained by using Macopharma’s tissue freezing bags, an aluminium-polyethylene
multilayer bag, in our tissue bank of the Centro Comunitario de Sangre y Tejidos de Asturias. Five hundred and twenty-seven
cancellous bone homografts were obtained from hospitals located 120 km around our Bank. The homografts were submitted to bacteriological
controls and sent to our bank in these bags. They were stored at −70 °C and sent in dry ice to about 50 hospitals, where the
tissue was bacteriologically controlled and grafted. Furthermore, the behaviour of these bags at −140 °C (vapour nitrogen)
or −196 °C (liquid nitrogen) was tested. Our results indicate that Macopharma aluminium-polyethylene bags are suitable for
the transporting and cryopreserving of cancellous bone homografts. These bags could also be used for keeping tissues in nitrogen
containers. 相似文献
2.
Babak Arjmand Seyed Hamidreza Aghayan Parisa Goodarzi Mohammad Farzanehkhah Seyed Mohamadjavad Mortazavi Mohamad Hossein Niknam Ali Jafarian Farzin Arjmand Soheyla Jebelly far 《Cell and tissue banking》2009,10(3):247-252
Iranian Tissue Bank prepares a wide range of human tissue homografts such as; heart valve, bone, skin, amniotic membrane and
other tissues for different clinical applications. The purpose of this study was to determine the seroprevalence of HTLV in
tissue donors. About 1,548 tissue donors were studied during a 5-years period by ELISA assays. HTLV1,2—antibodies were tested for all of donors with other tests upon American Association of Tissue Banks (AATB) standards. About
25 (1.61%) out of 1,548 tissue donors were HTLV positive that 17 donors were male and 8 were female (female/male ratio was
approximately 47%). Regarding to the prevalence of HTLV among tissue donors and importance of cell and tissue safety and quality
assurance, we recommend that all blood, cell and tissue banks should be involved both routine serological methods and other
complementary tests such as polymerase chain reaction (PCR) for diagnosis of HTLV. 相似文献
3.
The history of using homologous cardiac valves dates back more than 30 years. Through the years emphasis was placed on the
optimization of graft retrieval, preservation techniques and clinical application. A cardiac homograft valve bank was established
at the Department of Cardiothoracic Surgery, University of the Free State, Bloemfontein in 1982. A retrospective analysis
was performed on all allograft data since 1984. Since the first valve was successfully procured and transplanted in 1984,
2,540 aortic and pulmonary homografts were harvested from 1,792 donors, of which 1,545 [989 (64%) aortic and 556 (36%) pulmonary]
were released for clinical use. Valves were discarded for various reasons, the main reasons being Human Immunodeficiency Virus
(32.4%), Hepatitis B (9.6%) and venereal diseases (8.9%). The mean donor age was 26.98 years with a male predominance of 1,368
males versus 424 females. The average ischemic time was 33 h mainly due to medico-legal autopsies exceeding the desired 24 h
time limit. The valves were disinfected in an antibiotic cocktail of Mefoxin, Piperacillin, Amikacin and Amphotericin B prior
to cryopreservation. The surgical procedures utilizing the majority of homografts were aortic valve replacements (42.9%),
aortic root replacements (19.3%) and right ventricular-pulmonary artery conduits (33.3%). The bank also supplied 23 other
centers with homografts (402 aortic and 301 pulmonary). The Bloemfontein bank has established itself over the years as a viable
and functional cardiac homograft bank. However, with increasing activity in the procurement arena and widened applications
in the operating room the role of the homograft seems assured but availability still remains a major concern. 相似文献
4.
Since there is no upper age limit for general organ donation, unlike heart valve donation, and since a quarter of all organ
donors are 65 years and older, we examined whether the heart valves from these donors are suitable as allografts. In the period
1999–2004 the aortic valve and pulmonary valve of 100 organ donors above 65 years of age were examined to establish whether
they would have been suitable as valve grafts. To compare the valve grafts above and below the age limit of 65 years, we used
data on the aortic and pulmonary valves of 380 organ donors below the age limit in the same time period. Examination of the
200 heart valves showed that – just like valves from donors below the age limit – 100 of them would have met the medical quality
standards for transplantation, which discriminate among optimal, suitable and unsuitable tissue morphology. The morphological
suitability of the aortic valves decreases rapidly during the 4th decade of life and near to the age limit only 6% of them
are accepted as grafts. The rate of potentially acceptable aortic valve grafts from organ donors aged over 65 years of 15%
is also small. By contrast, the pulmonary valves are not affected by age-related tissue changes that might reduce their transplantability.
The predominant majority (85%) of potential pulmonary valve grafts from organ donors over 65 years of age fulfilled the acceptance
criteria, half of them (48%) even showing good tissue quality. In light of these results the age limit was raised to 70 years
in 2005. 相似文献
5.
Juliette C. Young Mariella Marzano Rehema M. White David I. McCracken Steve M. Redpath David N. Carss Christopher P. Quine Allan D. Watt 《Biodiversity and Conservation》2010,19(14):3973-3990
Conflicts between the conservation of biodiversity and other human activities occur in all habitats and can impact severely
upon socio-economic and biological parameters. In a changing environment, with increasing pressure on ecosystem goods and
services and increasing urgency for biodiversity conservation, these conflicts are likely to increase in importance and magnitude
and negatively affect biodiversity and human well-being. It is essential, however, to better understand what is meant by ‘biodiversity
conflicts’ in order to develop ways to manage these effectively. In view of the complexity of the social and ecological contexts
of conflicts, this paper explores ‘biodiversity impacts’ linked to agricultural, forestry and other sectoral activities in
the UK. The paper then describes the transition from ‘biodiversity impacts’ to ‘biodiversity conflicts’, illustrating this
concept with specific examples. While generalisations relating to conflict management are made difficult by their unique contextual
settings, this paper suggests approaches for their management, based on the experiences of scientists who have been involved
in managing conflicts. We consider the role of science and scientists; trust and dialogue; and temporal and spatial scales
in biodiversity conflicts and highlight the combined role they play in successful biodiversity conflict management. Recommendations
are also made for future research on biodiversity conflicts in a changing environment. 相似文献
6.
The contributions of mycorrhizal fungi to the determination of plant community structure 总被引:10,自引:3,他引:7
While it is now widely accepted, even by ecologists, that most plants in the majority of ecosystems are infected by mycorrhizal
fungi, few experiments have been designed to investigate the function of the mutualism at the community level. Those involved
with mycorrhizal research have been largely preoccupied with questions of the mineral, particularly phosphorus, nutrition
of individual plants, while plant community ecologists have too often found it convenient, even when acknowledging the presence
of infection, to ignore its possible function in the ecosystem.
This presentation examines a selected number of seminal papers written by plant community ecologists and highlights some of
‘the most striking mysteries’ which they reveal. It describes experiments designed to determine whether knowledge of the presence
and activity of the mycorrhizal mycelium can help us to unravel the ‘mysteries’ which they define.
It is revealed that by having direct adverse effects upon seedlings of many ‘r’ selected species, while at the same time being
beneficial, if not essential, to those that are ‘K’ selected, the activities of the mycelium of VA fungi have a direct bearing
upon community composition. The extent to which ‘turf compatibility’ is actually a reflection of the compatibility of plant
species with the VA mycorrhizal mycelium is discussed and the possible role of the mycelium in consigning some species to
the ruderal habit is considered.
It is concluded that those attempting scientifically to understand, or managerially to manipulate, plant communities, without
recognizing the role of the mycorrhizal mycelium, do so at their peril, and it is recommended that scientists involved in
research on mycorrhiza extend their vision beyond the limited horizons which are currently so often defined by considerations
of the phosphorus nutrition of individual host plants. 相似文献
7.
Anne Fournier 《Biodiversity and Conservation》2011,20(9):1895-1910
Anthropological contributions that challenge several common perceptions on sacred sites are still poorly taken into account
in conservation and ecological studies. This paper aims at filling this gap and providing a better framework for biological
studies. Local concepts of natural sacred sites and their ritual administration were studied and the ritual practices relating
to the vegetation of these sites were analyzed in the Bwaba cultural area in West Burkina Faso. Our research shows that these
ritual practices are much more diverse and fluid than might have been supposed. Protection ‘by tradition’ is thus rather different
from what we call conservation. While vegetation does matter, its presence on sacred sites is not essential. In addition,
under certain circumstances, sacred sites may be transferred or reproduced elsewhere. Attention is drawn to the inadequacy
of ‘sacred woods’ as a category, in an ecological as well as an anthropological sense. Even if wooded shrines may contribute
to biodiversity conservation as a side-effect of their religious purpose, the idea that they fundamentally are ‘endogenous’
nature conservatories must be disproved. 相似文献
8.
This article describes the slight impact of Lysenkoism upon Polish botany. I begin with an account of the development of
plant genetics in Poland, as well as the attitude of scientists and the Polish intelligentsia toward Marxist philosophy prior
to the World War II. Next I provide a short history of the introduction and demise of Lysenkoism in Polish science, with a
focus on events in botany, in context with key events in Polish science from 1939 to 1958. The article outlines the little
effects of Lysenkoism upon botanists and their research, as well as how botanists for the most part rejected what was often
termed the “new biology.” My paper shows that though Lysenko’s theories received political support, and were actively promoted
by a small circle of scientists and Communist party activists, they were never accepted by most botanists. Once the political
climate in Poland altered after the events of 1956, Lysenko’s theories were immediately abandoned. 相似文献
9.
Building a 2010 biodiversity conservation data baseline: contributions of the Group on Earth Observations 总被引:1,自引:0,他引:1
Characterizing, modeling, and monitoring the distribution and condition of the Earth’s biodiversity and ecosystems has a long
history of being aided by Earth Observation data and the models and derivative products that they support. At the global scale,
there need to be more coordinated efforts to acquire, process, analyze, and make available these observation data across all
disciplines, particularly since many applications use the same primary and derived data. Towards that end, the Group on Earth
Observations (GEO) is implementing the Global Earth Observing System of Systems. The purpose of this article is to provide
information on GEO’s goals and activities relevant to biodiversity and ecosystems. The article also describes the data that
would best serve as a year 2010 baseline in order to support the objectives of the Convention on Biological Diversity (CBD)
as well as many other international agreements, programs, and activities. Indeed, an assessment of existing biodiversity observations
with a concomitant recognition of the remaining gaps will promote the establishment of an integrated framework for biodiversity
observations in support of the CBD’s efforts. 相似文献
10.
P. S. Ramakrishnan 《Journal of biosciences》2001,26(4):465-479
In the context of over-consumption of natural resources in the name of development and rapid industrialization by a small
section of the human population that is rapidly growing, the world is currently faced with a variety of environmental uncertainties.
‘Global change’ covering a whole variety of ecological issues, and ‘globalization’ in an economic sense, are two major phenomena
that are responsible for these uncertainties. There is increasing evidence to suggest that the developing countries more than
the developed, particularly the marginalized traditional (those living close to nature and natural resources) societies would
be the worst sufferers. In order to cope with this problem in a situation where the traditional societies have to cope with
rapidly depleting biodiversity on which they are dependant for their livelihood, there is an urgent need to explore additional
pathways for sustainable management of natural resources and societal development. Such pathways should be based on a landscape
management strategy, that takes into consideration the rich traditional ecological knowledge (TEK) that these societies have.
This is critical because TEK is the connecting link between conservation and sustainable development. This paper explores
the possibilities in this direction through a balanced approach to development, that links the ‘traditional’ with the ‘modern’,
in a location-specific way. 相似文献
11.
This paper describes and analyses how discourses of conservation and development as well as migrant labour practices can be
understood as transnational dynamics that both cement and complicate transnational relations. It also looks into how these
dynamics articulate with, shape and are being shaped by ‘the local’. Focusing on the north-eastern boundary of Lesotho in
the area of the ‘Maloti-Drakensberg transfrontier conservation and development project’, we show how conflictual situations
put the ethnographic spotlight on the ways in which ‘local people’ in Lesotho deal with dual forces of localisation and transnationalisation.
We argue that they accommodate, even appropriate, these dual pressures by adopting an increasingly flexible stance in terms
of identity, alliances, livelihood options and discourses. 相似文献
12.
Rubina P. Shaikh Viness Pillay Yahya E. Choonara Lisa C. du Toit Valence M. K. Ndesendo Priya Bawa Shivaan Cooppan 《AAPS PharmSciTech》2010,11(1):441-459
Membrane technology is broadly applied in the medical field. The ability of membranous systems to effectively control the
movement of chemical entities is pivotal to their significant potential for use in both drug delivery and surgical/medical
applications. An alteration in the physical properties of a polymer in response to a change in environmental conditions is
a behavior that can be utilized to prepare ‘smart’ drug delivery systems. Stimuli-responsive or ‘smart’ polymers are polymers
that upon exposure to small changes in the environment undergo rapid changes in their microstructure. A stimulus, such as
a change in pH or temperature, thus serves as a trigger for the release of drug from membranous drug delivery systems that
are formulated from stimuli-responsive polymers. This article has sought to review the use of stimuli-responsive polymers
that have found application in membranous drug delivery systems. Polymers responsive to pH and temperature have been extensively
addressed in this review since they are considered the most important stimuli that may be exploited for use in drug delivery,
and biomedical applications such as in tissue engineering. In addition, dual-responsive and glucose-responsive membranes have
been also addressed as membranes responsive to diverse stimuli. 相似文献
13.
Martin Maiden 《Morphology》2009,19(1):59-86
This study examines some cases of heteroclisis in the history of Romanian dialects, and concludes that the data call for a
reconsideration of Stump’s distinction (Language 82:279–322, 2006) between ‘cloven’ heteroclisis, where the intraparadigmatic
‘split’ is aligned with some morphosyntactic feature distinction, and ‘fractured’ heteroclisis, where this is not the case
and the pattern of heteroclisis is purely morphological. Stump’s account creates the impression that the ‘cloven’ variety
is universally predominant, and that the ‘fractured’ variety tends to follow very closely the available ‘cloven’ patterns
of the language. I shall suggest, instead, that the ‘fractured-only’ situation may in fact underlie heteroclisis cross-linguistically,
the phenomenon being in general sensitive not directly to morphosyntactic content, but rather to characteristic, and often
purely ‘morphomic’, patterns of stem-allomorphy.
Research for this paper was undertaken as part of the Arts and Humantities Research Council-funded project Autonomous Morphology in Diachrony: comparative evidence from the Romance Languages, currently being conducted at Oxford University. 相似文献
14.
Sylvi Haldorsen Hasan Akan Bahattin ?elik Manfred Heun 《Vegetation History and Archaeobotany》2011,20(4):305-318
The domestication of the Neolithic founder crops of the Near East has recently been a topic of debate particularly with respect
to how rapidly the domestication of these crops occurred. One school of thought maintains that these processes lasted several
thousand years (‘protracted model’ with ‘gathering’, ‘cultivation’ and ‘domestication’ as three stages of a continuum, each
taking up to several thousand years), while another favors the view that domestication occurred much more quickly, over several
hundred years at most (‘rapid transition’). Our study focuses on one of these crops, 1-grained domesticated Einkorn wheat,
incorporating data from geology, vegetation history, and climate. In the Karacadağ region of southeastern Turkey, where 1-grained
Einkorn wheat was domesticated, the climate was severe (i.e. cold and dry) during the Younger Dryas. The climate of the Younger
Dryas acted as boundary during which a) conditions were not suitable for ‘cultivation’, and b) Einkorn would have retreated
to refugia exhibiting more suitable moisture-bearing soils that would have made ‘gathering’ difficult. Around 11600 cal. b.p., the Younger Dryas ended and a very rapid climatic amelioration commenced at the beginning of the Early Holocene, enabling
grasses to spread throughout the region. A ritual PPNA/PPNB site (G?bekli Tepe) and associated PPNB settlements such as Nevali
?ori and ?ay?nü were established at this time. In the settlements of Nevali ?ori and Cafer H?yük, the oldest domesticated
Einkorn was found in the earliest archaeological layers. This confirms that the inhabitants made use of domesticated 1-grained
Einkorn from the very beginning of settlement activity, although they continued to practice a mixed lifestyle as hunter-gatherers
and farmers. For ?ay?nü the issue is more complex, but here domesticated Einkorn also appears around the same time. In summary,
by 10400 cal. b.p. domesticated 1-grained Einkorn was present in large quantities at a variety of sites. This would give a maximum window of
time lasting approximately 1,200 years and is therefore not in agreement with the ‘protracted’ model but would be consistent
with a ‘rapid transition’. It is improbable that the ‘cultivation’ of wild Einkorn was practiced in the Karacadağ region,
since wild Einkorn was plentiful during the favorable growing conditions following the Younger Dryas, making it more likely
that ‘gathering’ would have been practiced. Because Einkorn has not been found in early settlements in the southern Levant,
this crop cannot have been ‘gathered’ and ‘cultivated’ there but instead was ‘domesticated’ independently and solely in southeastern
Turkey. Therefore, the YD acts as a boundary, providing a maximum time frame for 1-grained Einkorn domestication. 相似文献
15.
Bio-inspired polymeric heart valves (PHVs) are excellent candidates to mimic the structural and the fluid dynamic features of the native valve. PHVs can be implanted as prosthetic alternative to currently clinically used mechanical and biological valves or as potential candidate for a minimally invasive treatment, like the transcatheter aortic valve implantation. Nevertheless, PHVs are not currently used for clinical applications due to their lack of reliability. In order to investigate the main features of this new class of prostheses, pulsatile tests in an in-house pulse duplicator were carried out and reproduced in silico with both structural Finite-Element (FE) and Fluid-Structure interaction (FSI) analyses. Valve kinematics and geometric orifice area (GOA) were evaluated to compare the in vitro and the in silico tests. Numerical results showed better similarity with experiments for the FSI than for the FE simulations. The maximum difference between experimental and FSI GOA at maximum opening time was only 5%, as compared to the 46.5% between experimental and structural FE GOA. The stress distribution on the valve leaflets clearly reflected the difference in valve kinematics. Higher stress values were found in the FSI simulations with respect to those obtained in the FE simulation. This study demonstrates that FSI simulations are more appropriate than FE simulations to describe the actual behaviour of PHVs as they can replicate the valve-fluid interaction while providing realistic fluid dynamic results. 相似文献
16.
17.
Ryan F. Hechinger Kevin D. Lafferty Frank T. Mancini III Robert R. Warner Armand M. Kuris 《Evolutionary ecology》2009,23(5):651-667
Parasitic castration is an adaptive strategy where the parasite usurps its host’s phenotype, most notably the host’s reproductive
effort. Though castrators are loosely known to be large relative to their hosts (compared to typical parasites), their mass
has rarely been quantified and little is known about size variation, even if such variation exists. By cross-sectioning snails,
we examined intra- and inter-specific variation in the parasite/host mass of 15 trematode species that castrate the California
horn snail, Cerithidea californica. Trematode species occupied 14–39% (mean = 20.3%) of an infected snail’s soft tissue mass. Intraspecific variation in castrator
mass fluctuated with variables that covary with energy available for host reproduction. Specifically, trematode mass was 24%
higher in summer than in winter, 15% greater in snails from intertidal flats than from tidal channels, and increased with
host mass to the 1.37 power (a finding contrary to that previously documented for other types of parasites). Relative body
mass differed across trematode species, varying interspecifically with: (1) taxonomic family, (2) host tissue use (larger
species used more types of host-tissue), (3) position in the trematode interspecific competitive dominance hierarchy (the
two most subordinate species were the largest, otherwise size tended to increase with dominance), and (4) type of host used
by offspring (species whose offspring infect relatively predictably occurring benthic invertebrates were larger than those
infecting transient vertebrates). Our findings suggest that ecological constraints and life history trade-offs between reproduction
and survival influence the mass of these very large parasites. 相似文献
18.
19.
Rosario Michael Piro 《Biology & philosophy》2011,26(4):595-602
Although much has been learned about hereditary mechanisms since Gregor Mendel’s famous experiments, gene concepts have always
remained vague, notwithstanding their central role in biology. During over hundred years of genetic research, gene concepts
have often and dynamically changed to accommodate novel experimental findings, without ever providing a generally accepted
definition of the ‘gene.’ Yet, the distinction between ‘regulatory genes’ and ‘structural genes’ has remained a common theme
in modern gene concepts since the definition of the operon-model. This distinction is now challenged by recent findings which
suggest that, at least in eukaryotes, structural genes may in many situations have a regulatory function that is independent
of the function of the gene product (protein or non-coding RNA molecule). This brief paper discusses these new findings and
some possible implications for the notion of the ‘regulatory gene.’ 相似文献
20.
This study analyzed genetic differences of 19 cultivars selected from somaclonal variants of Syngonium podophyllum Schott along with their parents as well as seven additional Syngonium species and six other aroids using amplified fragment length polymorphism (AFLP) markers generated by 12 primer sets. Among the 19 somaclonal cultivars, ‘Pink Allusion’ was selected from ‘White Butterfly’. Tissue culture of ‘Pink Allusion’ through organogenesis resulted in the development of 13 additional cultivars. Self-pollination of ‘Pink Allusion’ obtained a cultivar, ‘Regina Red Allusion’, and tissue culture propagation of ‘Regina Red Allusion’ led to the release of five other cultivars. The 12 primer sets generated a total of 1,583 scorable fragments from all accessions, of which 1,284 were polymorphic (81.9%). The percentages of polymorphic fragments within ‘White Butterfly’ and ‘Regina Red Allusion’ groups, however, were only 1.2% and 0.4%, respectively. Jaccard's similarity coefficients among somaclonal cultivars derived from ‘White Butterfly’ and ‘Regina Red Allusion’, on average, were 0.98 and 0.99, respectively. Seven out of the 15 cultivars from the ‘White Butterfly’ group and three out of six from the ‘Regina Red Allusion’ group were clearly distinguished by AFLP analysis as unique fragments were associated with respective cultivars. The unsuccessful attempt to distinguish the remaining eight cultivars from the ‘White Butterfly’ group and three from the ‘Regina Red Allusion’ group was not attributed to experimental errors or the number of primer sets used; rather it is hypothesized to be caused by DNA methylation and/or some rare mutations. This study also calls for increased genetic diversity of cultivated Syngonium as they are largely derived from somaclonal variants. 相似文献