共查询到20条相似文献,搜索用时 15 毫秒
1.
Al-Qattan MM 《Plastic and reconstructive surgery》2001,108(2):336-342
Pericranial flaps are thin and, hence, their volumes are small. Therefore, their use for soft-tissue augmentation has not been popular. In this article, the author introduces a new concept: the use of a multifolded pericranial flap as a "plug" or a "pad" for localized contour defects. Eight patients were included in the study. In all cases, an anteriorly based pericranial flap was used, and the flap was folded on itself several times to increase its bulk. The results were satisfactory in all patients. The literature on the topic is reviewed, and the blood supply of pericranial flaps is discussed. 相似文献
2.
Borrello ME 《Perspectives in biology and medicine》2004,47(1):15-31
Petr Alekseyevich Kropotkin (1842-1921) and Vero Copner Wynne-Edwards (1906-1997) developed evolutionary theories that emphasized social groups and cooperation rather than the organism-level natural selection of standard Darwinian theory. The most important reason for their alternative interpretations was their experience as field naturalists. Kropotkin and Wynne-Edwards worked in arctic environments and were impressed by aspects of the natural world that differed significantly from those experienced by Darwin or Wallace. These field experiences led to their emphasis on mutual aid and group selection, respectively. Understanding the development of their theories helps to illuminate the continuing debates over evolutionary theory and the current resurgence of interest in group selection. 相似文献
3.
"太岁"是一种存在于地球上分类地位尚不清楚的生物体。对实验室保藏的7种不同的"太岁"样品进行了生物学组分的定性定量分析,旨在科学地了解"太岁"的组成成分,同时为"太岁"有效成分的开发利用和分类鉴定提供理论依据。对实验室保藏的7种"太岁"样品做生物组分及含量分析,具体包括:苯酚硫酸法测粗多糖含量、凯氏定氮法测粗蛋白含量、索氏提取法测粗脂肪含量、钒钼酸显色法测核酸含量、灼烧重量法测粗灰分含量、恒温干燥法测水分含量、原子吸收法测微量元素含量。实验结果表明,7种"太岁"样品含水量均较高,除LNUT006含水量73.58%外,其余"太岁"样品均达到90%以上;"太岁"样品中粗多糖含量在8.97~46.57 mg/g之间,其中LNUT006多糖含量明显高于其他"太岁"样品;粗蛋白含量在20.35~184.18 mg/g之间,其中LNUT006蛋白含量明显高于其他"太岁"样品;"太岁"样品中净核酸含量在2.053~35.128 6μg/g之间;灰分含量在42.93~246.4 mg/g之间;"太岁"样品钙、铁含量较高,分别为2 907.09μg/g和3 929.09μg/g,铅、镉含量最低。首次对未知生物"太岁"样品的组成成分进行初步系统的研究,为明确其组分和对其进一步的开发利用均有很重要的意义。 相似文献
4.
蕲州地区的蕲艾、青蒿、黄花蒿与茵陈的考订 总被引:3,自引:0,他引:3
<正> 蕲州是我国中药材主要产地之一,是湖北省蕲春县的一个集镇,,是我国中医药大师李时珍的家乡。该地区生长的菊科蒿属植物Artemisia Linn。颇多,其中入药的有十余种,并在李时珍《本草纲目》中曾有记载。这里仅对该地区常见入药的蕲艾、青蒿、黄花蒿与茵陈结合《本草纲目》记载的材料作初步的考订。 相似文献
5.
All children''s consultations with their general practitioner over a 12 month period in a small urban practice were analysed. Overall consultation rates ranged from 2.2 per child a year for 8 to 11 year olds, to 6.8 for those under 2. Families were grouped according to their average rate of new consultation for children, standardised for age. Families with higher consulting rates scored higher on an index of economic disadvantage, with mothers who scored higher on a test of "tendency to consult" and who were less educated than those in lower consulting families. The presence of any doctor-defined "significant disease" in any child was highly correlated with the family''s consultation rate. 相似文献
6.
Merzhanova GKh Kuleshova EP Grigor'ian GA 《Zhurnal vysshe? nervno? deiatelnosti imeni I P Pavlova》2006,56(6):805-812
In this paper the problem of "impulsive" and "self-control" behaviour in animals and the experimental models for their assessment are discussed. It is pointed out that a widely accepted model for assessment of impulsive behaviour in animals predominantly measures their ongoing properties of impulsivity/self-control independently on belonging them to the certain types of higher nervous activity. In contrary, our model at the first instance assesses the typological characteristics of animals, including impulsivity and self-control, by their abilities to perform or not to perform an appropriate behaviour. The differences in the data obtained by these two different models and the possible reasons for it are discussed. 相似文献
7.
B Przybylska 《Zeitschrift für mikroskopisch-anatomische Forschung》1989,103(2):329-335
Both qualitative and quantitative comparative studies of "dark" and "light" pinealocytes of the porcine pineal gland have been carried out. These cells differ from each other in their electronic density of cytoplasm, shape of nucleus, the structure of membrane bound dense bodies and the number of microtubules and smooth endoplasmic reticulum. The membrane bound dense bodies--characteristic structures of pig pinealocytes as well dense core vesicles occur in both types of cells. The relative volume of the majority of the cells' organellae apart from the Golgi apparatus, also do not show any significant difference. The results obtained support a functional basis for pinealocyte differentiation in the porcine pineal gland. 相似文献
8.
S Yamamoto 《Free radical biology & medicine》1991,10(2):149-159
Lipoxygenase is a dioxygenase which incorporates one molecule of oxygen at a certain position of unsaturated fatty acids such as arachidonic and linolenic acids. The enzymatic oxygenation of unsaturated fatty acids is stereospecific concomitant with a stereoselective abstraction of hydrogen atom. Fatty acid cyclooxygenase is an atypical lipoxygenase incorporating two molecules of oxygen, and initiates the biosynthesis of prostaglandins and thromboxanes. Arachidonate 5-lipoxygenase is responsible for the leukotriene synthesis. No such bioactive compound has been found as a metabolite of the 12- and 15-lipoxygenase pathways, and their physiological roles are still unclarified. These enzymes have been purified, and their molecular and catalytic properties have been investigated. Their cDNA clones have been isolated, and their nucleotide sequences have been determined deducing the primary structures of the enzymes. 相似文献
9.
Interaction of hematopoietic stem cells (HSCs) with their particular microenvironment, or niche, is critical for adult hematopoiesis in the bone marrow (BM). Arai et al. (this issue of Cell) demonstrate that HSCs that express the receptor tyrosine kinase Tie2 are quiescent. Ang-1, the ligand for Tie2, enhanced the ability of HSCs to become quiescent and also induced their adhesion to bone, protecting them from stresses that suppress hematopoiesis. These data suggest that the Ang-1/Tie2 signaling pathway plays a crucial role in the maintenance of HSCs in a quiescent state in the BM niche. 相似文献
10.
This paper reports data on cytological peculiarities of neurons of two main zones of sexual dimorphism in brain amygdala (dorsomedial nucleus and anterior cortical nucleus). The main attention was paid to some characteristics of "dark" and "pale" cells found in the amygdaloid complex for the first time. It is supposed that the dark and pale cells are targets for gonadal steroids, whose cyclic changes in concentration in the blood difined their functional states. Though the ultrastructure of dark and pale cells of the amygdaloid complex is similar to that of neurosecretory cells of hypothalamus, there are necessary electron microscopic and cytochemical evidences. 相似文献
11.
Consoli SG 《Médecine sciences : M/S》2006,22(2):197-200
To construct a coherent identity, humans must distinguish what belongs to the external, perceived world from what belongs to their own inner world and the inner world of other individuals. Based on the theory developed by S. Freud and on work by ethologists, a number of psychoanalysts (J. Bowlby, R.A. Spitz, D.W. Winnicott, etc.) have underlined the importance of early tactile exchanges with the mother if a child is to become an autonomous individual who feels secure within what he or she perceives to be sound and reliable mental and physical boundaries. More recently, other psychoanalysts (E. Bick, W.R. Bion, etc.) have studied the fantasized mental structures that form the limits between an individual's inner mental space and the external world (including other individuals). As part of this theoretical psychoanalytical movement, Didier Anzieu, a French psychoanalyst, started to develop the concept of the "Moi-peau" in 1974. The "Moi-peau" designates a fantasized reality that a child uses during its early development to represent itself as "me", based on its experience of the body surface. The child, enveloped in its mother's care, fantasizes of a skin shared with its mother: on one side the mother (the outer layer of the "Moi-peau"), and on the other side the child (the inner layer of the "Moi-peau"). These two layers must separate gradually if the child is to acquire its own me-skin. D. Anzieu's work allowed dermatologists and other specialists, such as pediatricians, to focus on the quality of early tactile exchanges between a mother and her child, including the child with a chronic skin disorder. It also helped dermatologists to recognize patients with "borderline" states, which are particularly frequent in dermatology (ereutophobia, dysmorphophobia, tattooing, self-mutilation, artefacta dermatitis). These borderline patients are adults who, as a result of their mental conflicts, adopt defense mechanisms derived from both neurotic and psychotic functioning. Their complaints reflect difficulties with the solidity of their mental and physical limits: their real skin is metaphorically linked to the fantasized mental structure that delimits the individual mental space. Among other clinical characteristics, they have a "pathology of action" and frequently attack their own skin, paradoxically, in order to test the solidity and reliability of their own limits. Finally, D. Anzieu's work encouraged dermatologists to use psychotherapeutic approaches in parallel to classical dermatologic approaches, when necessary, and helped them better understand how psychoanalysts work with patients who have not yet acquired their own "Moi-peau". As a result, D. Anzieu was among the first to reconcile dermatologists and psychoanalysts. 相似文献
12.
Marck KW 《Plastic and reconstructive surgery》2003,111(5):1702-1707
Noma (necrotizing ulcerative stomatitis, stomatitis gangrenosa, or cancrum oris) is a devastating orofacial gangrene that occurs mainly among children. The disease has a global yearly incidence of 140,000 cases and a mortality rate of approximately 90 percent. Patients who survive noma generally suffer from its sequelae, including serious facial disfigurement, trismus, oral incontinence, and speech problems. The medical history of noma indicates that the disease was already known in classical and medieval civilizations in Europe. In the sixteenth and seventeenth centuries, Dutch chirurgeons clearly described noma as a clinical entity and realized that the popular name "water canker" was not sufficient, because this quickly spreading ulceration in the faces of children was different from "cancer." In the eighteenth century, awareness that noma is related to poverty, malnutrition, and preceding diseases such as measles increased in northwestern Europe. In the first half of the nineteenth century, extensive surgical procedures were described for the treatment of the sequelae of noma. At the end of that century, noma gradually disappeared in the Western world because of economic progress, which gave the poorest in society the opportunity to feed their children sufficiently. Only in the twentieth century were effective drugs (sulfonamides and penicillin) against noma developed, as well as adequate surgical treatment for the sequelae of noma. These modes of treatment remain inaccessible for the many present-day victims of noma because of their extreme poverty. The only truly effective approach to the problem of noma throughout the world is prevention, namely, combating the extreme poverty with measures that lead to economic progress. In the meantime, medical doctors in the Western world should not forget their own history and ignore this global health problem; rather, they should face "the face of poverty" with the eyes of mercy and concern suited to their profession. 相似文献
13.
DeSalle R Schierwater B 《BioEssays : news and reviews in molecular, cellular and developmental biology》2008,30(11-12):1043-1047
Metazoa are one of the great monophyletic groups of organisms. They comprise several major groups of organisms readily recognizable based on their anatomy. These major groups include the Bilateria (animals with bilateral symmetry), Cnidaria (jellyfish, corals and other closely related animals), Porifera (sponges), Ctenophores (comb jellies) and a phylum currently made up of a single species, the Placozoa. Attempts to systematize the relationships of these major groups as well as to determine relationships within the groups have been made for nearly two centuries. Many of the attempts have led to frustration, because of a lack of resolution between and within groups. Other attempts have led to "a new animal phylogeny". Now, a study by Dunn et al., using the expresssed sequence tag (EST) approach to obtaining high-throughput large phylogenetic matrices, presents an "even newer" animal phylogeny. There are two major aspects of this study that should be of interest to the general biological community. First, the methods used by the authors to generate their phylogenetic hypotheses call for close examination. Second, the relationships of animal taxa in their resultant trees also prompt further discussion. 相似文献
14.
实施“三高”教学,创建“微生物学实验”课程新体系 总被引:21,自引:1,他引:21
深化微生物实验教学改革,实施“高起点、高效率、高质量”教学,从调整教学内容,改革教学方法,建立和完善考评机制入手,创建“以基础知识和基本技能为基础性内容,以创新能力培养为核心内容”的微生物学实验课程新体系,激发了学生对微生物学实验的兴趣,培养了学生独立思考、创新思维和综合动手的能力。 相似文献
15.
We all possess T cells with autoaggressive potential. Knowledge of their regulation is crucial for elucidating pathogenetic pathways and designing effective treatments for autoimmune diseases. A novel mechanism of T-cell silencing--in an autoimmune model--has recently been identified and is termed "epitope theft". The "thieves" are naive CD8+ T cells, which apparently "steal" MHC-class-I-antigen complexes from antigen-presenting cells (APCs). The deprived APCs can no longer activate other potentially pathogenic naive CD8+ T cells that are specific for the same epitope. This phenomenon is a previously unrecognized antigen-specific mode of protection against autoimmunity. 相似文献
16.
"Impoverished" and "enriched" living conditions influence the proliferation and survival of neurons in crayfish brain 总被引:2,自引:0,他引:2
New neurons are added to two bilateral clusters of neurons in crayfish brain throughout their lives. These interneurons are associated with the olfactory and accessory lobes, areas of the brain that receive primary olfactory information and higher order inputs from the visual and tactile receptor systems. The rate of cell proliferation in these four clusters, revealed by BrdU labeling, is sensitive to the living conditions of the animals: individuals isolated in small spaces (impoverished condition) exhibit a lower rate of cell proliferation in comparison to their siblings living together in larger areas (enriched condition), although both groups were fed to satiation. Reduction in the rate of proliferation can be measured 1 to 2 weeks after the animals are subjected to the impoverished condition. Counts of the labeled neurons that survive after 4 weeks of subjection to the two conditions show that fewer new neurons survive in the brains of animals that have lived for 2 weeks in the impoverished condition in comparison to their siblings living in the enriched conditions. Factors such as surface area, depth of water, and social interaction can all play a role in determining both the rate of new neuron production and the incorporation of the new neurons into the brain of freshwater crayfish. The results indicate a high degree of neuronal plasticity in the crayfish brain that is highly sensitive to the conditions under which the animals are kept. 相似文献
17.
"Old" human erythrocytes showed a 21.2% decrease in cell surface area and a 2% decrease in the number of WGA receptor sites, but a 27% increase in the distribution density of the WGA (lectin) receptor site, when compared with "young" human erythrocytes. For a list of lectin abbreviations, see Materials and methods). Both "young" and "old" erythrocytes exhibited very weak binding activity for 125I-labeled PNA, but there was no difference in binding activity for PNA between "young" erythrocytes and "old" ones. Compared with "young" erythrocytes, decreases in the number and distribution density of receptor sites for five lectins including LPA, Con A, RCA-II, SBA and BPA on the cell surface were observed in aged erythrocytes. "Old" erythrocytes also showed a decrease in the number of PHA-E receptor sites, while the distribution density of the same receptor site remained unchanged. In view of these and other observations, it is thought that human erythrocyte aging is accompanied by elimination of some glycoconjugates which have affinity for six lectins, LPA, Con A, RCA-II, PHA-E, SBA and BPA, whereas no WGA receptor-containing glycoconjugates are released from erythrocyte membranes. Elimination of the glycoconjugates results in shrinkage of erythrocytes to reduce their cell surface areas. 相似文献
18.
When protanopes or deuteranopes arrange the Farnsworth Dichotomous Test colors in order of similarity, they reveal their lack of red/green hue discriminations by alternating chips that the normal trichromat sees as reddish and greenish test colors. The dichromatic orderings follow a systematic variation in saturation of blue hues through neutral and into yellow hues as described by theory for each of the two types. Some dichromats who show the typical test behavior nevertheless use reddish and greenish hue terms appropriately when instructed to name the same test colors. Lightness cues are probably used by these dichromats in the naming task but ignored in the perceptual similarity task. Thus, unlike normal trichromats, who use similar names for perceptually similar colors, dichromats may use dissimilar names for perceptually similar colors. In this way they can achieve concordance with the normative language system despite its discordance with their impoverished color perceptions. 相似文献
19.
Morrison AR 《Perspectives in biology and medicine》2002,45(4):606-619
Scientists frequently disagree on the interpretation of data. Such disagreements follow an informal set of rules, where one assumes that the contestants are honestly engaged even though biases may cloud their minds. A new group of individuals with medical training operates under a different set of rules, however: any statement or argument may be used to support the animal rightists' contention that using animals to advance human medicine is wrong. These "medical scientists" pervert the scientific discourse in which most of us engage. Their fabrications are egregious. They take legitimate scientists' statements out of context, construct statements out of larger passages to twist arguments in their favor, and cite works that actually are contrary to their arguments for effect. This essay reveals the distortions by a number of such medically trained individuals that I and several colleagues have uncovered. 相似文献
20.
人类基因组测序的结束为生命科学领域展开了全新的一章.尽管已经得到了人类基因组的序列,但是隐藏在DNA序列中的功能基因,它们之间的相互作用以及对整个机体的意义大部分有待发掘.近些年来形成的“反向生物学”为免疫功能基因的发现、功能的研究及其应用价值提供了一套全新的技术与思路. 相似文献