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1.
Controversy surrounds the diagnosis, classification, and therefore the epidemiology of those tumors which have been designated as mesotheliomas. The group includes lesions which are as broadly different as benign fibrous lesions which some authors refer to as fibromas and anaplastic tumors which are extremely difficult to differentiate from peripheral lung cancers. The former are benign tumors which are usually readily resected and therefore cured. The latter are unresectable tumors which are invariably fatal and which may terminate with extensive metastatic disease. The reasons for including all of these lesions under the category of mesothelioma and the differential diagnosis of the various types is discussed.  相似文献   

2.
The purple nonsulfur photosynthetic eubacterium Rhodobacter capsulatus is a versatile organism that can obtain cellular energy by several means, including the capture of light energy for photosynthesis as well as the use of light-independent respiration, in which molecular oxygen serves as a terminal electron acceptor. In this study, we have identified and characterized a novel gene, senC, mutations in which affect respiration as well as the induction of photosynthesis gene expression. The protein coded by senC exhibits 33% sequence identity to the yeast nucleus-encoded protein SCO1, which is thought to be a mitochondrion-associated cytochrome c oxidase assembly factor. Like yeast SCO1, SenC is required for optimal cytochrome c oxidase activity in aerobically grown R. capsulatus cells. We further show that senC is required for maximal induction from the puf and puh operons, which encode the structural polypeptides of the light-harvesting and reaction center complexes.  相似文献   

3.
Traffic in one direction on a multilane highway is considered, and a general expression for the number of cars which pass a car travelling at a given velocity, as well as the number of cars which the given car passes, is derived for the case when the speeds of different cars are distributed in some arbitrary manner. Closed expressions are derived and discussed for a rectangular distribution. Each passing by another car or of another car is considered as a distracting stimulus which affects the reaction times of the driver. Using previously derived expressions for the safe speed as a function of reaction times, expressions for the safe average speed are derived, in terms of the volume of traffic and of the spread of the distribution of speeds.  相似文献   

4.
Downie J 《Bioethics》1990,4(3):216-226
The connection between brain life and brain death is neither as simple nor as defensible as it might at first appear. The problem rests with the two dominant competing definitions of death:...the loss of that which is necessary for the organism to continue to function as a whole;....the loss of that which is essentially significant to the nature of the organism... If death is understood as the loss of that which is necessary for the continued functioning of the organism as whole, then the apparent symmetry breaks down. If...death could be understood as the loss of that which is essentially significant to the nature of the organism....consciousness, then the symmetry would hold. However, that definition of death is indefensible. Therefore...statements about the status of anencephalic infants and early human embryos based upon a connection between brain death and brain life are unfounded.  相似文献   

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7.
In Aspergillus several types of test systems have been developed for detection of chemicals which induce aneuploidy and/or malsegregation of chromosomes. Results from 23 papers were reviewed in which numerical data for 42 chemicals had been reported. The test systems fall into two groups. One group includes all purely genetic tests that detect euploid mitotic segregants from heterozygous diploids and identify these either as products of malsegregation of chromosomes or as products of crossing-over (13 papers, several reviewed in detail previously; K?fer et al. (1982) and Scott et al. (1982)). The other group includes tests that treat haploid or diploid strains and detect aneuploids as unstable abnormally growing segregants which can be identified as specific disomics or trisomics by their characteristic phenotypes. In addition, such tests characterize abnormal segregants from heterozygous diploids by correlating phenotypes with patterns of genetic segregation in spontaneous euploid sectors. This analysis makes it possible to distinguish between induced primary aneuploidy of whole chromosomes and partial tri- or monosomy resulting from chromosome breakage and secondary spontaneous malsegregation (10 papers). Based on results of both types of tests, it is postulated that chemicals which cause increases of euploid malsegregants, but not of crossovers, normally induce aneuploids as primary products (as shown for 7 of the 14 cases). These include compounds which damage spindles or membranes (especially the well-known haploidizing agents) and generally are effective only when growing cells are exposed. (8 chemicals that may belong in this category could not be classified for certain, because information was insufficient.) On the other hand, chemicals which cause increases of all types of euploid segregants (11 cases), mostly induce drastic mutations and aberrations as primary effects and cause spontaneous malsegregation or crossing-over only as secondary events (as demonstrated for radiation-induced abnormals). In addition, a few chemicals were negative, because they increased only crossing-over or showed no increased segregation at all at concentrations which reduced survival or growth rate (9 cases). Recommendations are made for standardization of methods and protocols. New tester strains and specific procedures are outlined which should be useful for conclusive tests of chemicals that may induce aneuploidy.  相似文献   

8.
A general nonparametric approach to asymptotic multiple test procedures is proposed which is based on relative effects and which includes continuous as well as discontinuous distributions. The results can be applied to all relevant multiple testing problems in the one‐way layout and include the well known Steel tests as special cases. Moreover, a general estimator for the asymptotic covariance matrix is considered that is consistent even under alternative. This estimator is used to derive simultaneous confidence intervals for the relative effects as well as a test procedure for the multiple nonparametric Behrens‐Fisher problem.  相似文献   

9.
Nakajima M  Taniguchi N 《Genetica》2001,111(1-3):279-289
The guppy, Poecilia reticulata, is one of the most famous tropical ornamental fish in the world. There are many varieties and breeds which have been bred by aqua lists for many years. The guppy has frequently been used as model organism for experiments in fish genetics because of its short life cycle, ease of breeding and reproductive capacity. The laboratory strains which were created from local (Japanese) strains and varieties were used as an experimental genetic model for aquaculture. These laboratory strains were maintained as closed colonies for five to 20 years in our laboratory. One of the roles of model experiments in fish genetics to perform experiments which take a long time in which are commercially important, such as genetic drift, as the effect of inbreeding during the growth and maintenance of population. In this review, we mainly considered the results obtained in our laboratory relating to genetic drift, and the effects of inbreeding, heterosis and inheritance of quantitative traits.  相似文献   

10.
A certain practice associated with the tourism industry in Nepal's Chitwan district, the 'village walk', has become one way through which ethnic status can be expressed and claims to modernity made by local people. This phenomenon illustrates how globalizing processes reinforce the particulars of locality by providing people with new frameworks through which to interpret their societies. Thus, the ideology of modernity has replaced that of caste as the way in which Tharus and Brahmans in rural Nepal understand inter-ethnic relationships. Foreign tourists serve as a foil for this reinterpretation through the practice of the village walk, in which high-caste tourist guides conduct tourists on cultural tours of Tharu villages. The representation of Tharus as 'primitive', 'jungly', and living in another time meets both the desire of tourists for exotic experiences and that of high-caste Nepalese who wish to represent themselves as belonging to the modern world from which the tourists presumably come.  相似文献   

11.
A set of seven monoclonal antibodies (MAb) directed against outer membrane proteins of Pseudomonas aeruginosa has been examined by Western blot analysis, indirect immunofluorescence tests and subclass typing. The hybridoma cell line secreting MAb 6A4, which reacts with outer membrane protein I, belongs to the IgG2a subclass and crossreacts with the 17 P. aeruginosa serotypes as listed in the International Antigenic Typing System, was selected as source for the preparation of poly(A)+RNA which in turn was used as template for cDNA synthesis and cloning. Full length cDNA clones of the gamma heavy chain as well as the kappa light chain were obtained and characterized by nucleotide sequence analysis. The complete cDNA sequences coding for the heavy and light chains will be the prerequisite for the construction and heterologous expression of a chimeric human-mouse monoclonal antibody which might be used in therapy of P. aeruginosa infections.  相似文献   

12.
Basing on experiences made at the Anatomical Museum Basel often arising difficulties of conservation of ancient anatomical preparations are described. Criteria are named which allow the recognition of specific problems of various preparations, and the adequate solutions for fixation and conservation are given. These solutions, the compositions of which are described in detail, are suited for historical as well as for modern wet preparations. Thus, it is possible to save and stabilize also delicate preparations of former times, even those with faint hues can be renovated which afterwards show an increase of contrast and an improved preservation of colours. Furthermore, techniques are indicated for mounting and preservation of preparations in special containers made of acrylic glass. By means of these methods, the preservation of preparations as well as the cleaning and change of solutions are markedly improved.  相似文献   

13.
This article focuses on Ghanaian popular cinema,' which emerged in the late 1980s and has become a major form of entertainment for urban audiences. It shows that the filmmakers, who produce films in the video format which are very close to everyday life experiences and dreams, offer visions which they and their audiences regard as being similar to those provided by religious prophets and preachers. Watching these films allows for complex negotiations between the desires for transgression of the moral order, the longing to feel morally superior, and the striving for knowledge to understand one's world. On the basis of a detailed analysis of the film Women in Love, which conjures up a fantasy space located at the bottom of the sea where money and commodities are generated in exchange for sex and blood, this article argues that popular cinema is part and parcel of a new culture of vision, one characterized by the visualization of otherwise invisible fantasy spaces as well as by its easy accessibility through such modern mass media as video and TV. The article argues that these fantasy spaces should not be regarded as misguided distortions, but as sources for gaining insight into what Marx called “the religion of everyday life,” and thus as revelations of the fantasy dimension of global capitalism.  相似文献   

14.
We accept that we are responsible for the quality of life of animals in our care. We accept that the activities of man affect all the living things with which we share this planet. But we are slow to realize that as a result we have a duty of care for all living things. That duty extends to the breeding of animals for which we are responsible. When animals are bred by man for a purpose, the aim should be to meet certain goals: to improve the precision with which breeding outcomes can be predicted; to avoid the introduction and advance of characteristics deleterious to well-being; and to manage genetic resources and diversity between and within populations as set out in the Convention on Biological Diversity. These goals are summed up in the phrase precision animal breeding. They should apply whether animals are bred as sources of usable products or services for medical or scientific research, for aesthetic or cultural considerations, or as pets. Modern molecular and quantitative genetics and advances in reproductive physiology provide the tools with which these goals can be met.  相似文献   

15.
The health status of marine mammals such as harbour seals (Phoca vitulina) represents an indirect but powerful way for the assessment of environmental changes. The present work illustrates the first investigation and characterisation of Tf isolated from blood samples of North Sea harbour seals with a view to using changes in Tf isoform patterns as an additional parameter in extended studies of their health status. Therefore, an HPLC-ICP-MS approach has been developed which allows the highly resolved separation and fractionation of up to eight different Tf isoforms, as well as their sensitive and specific detection on the basis of their characteristic iron content. Molecule-specific detection techniques such as nanoLC-ESI-QTRAP-MS or MALDI-TOF-MS were used as complementary techniques to unambiguously identify the isolated proteins as Tf via cross species protein identification and to further characterise the molecular weight as well as the sialic acid content, which is responsible for the elution behaviour of the different isoforms during their ion exchange separation. A molecular mass above 80 kDa has been measured for the different seal Tf isoforms, which is in good agreement with the known molecular mass in other mammalian species, while the estimated pI of the different isoforms indicates some differences in comparison to other species. A number of homologies to known Tf sequences have been observed, which finally allows the cross species protein identification. The combined metallomics orientated analytical approach, which includes the complementary application of element and molecule-specific detection techniques, opens up interesting possibilities for the fast and targeted isolation and identification of a diagnostically relevant metal containing protein from an un-sequenced mammalian species prior to its utilisation in extended studies.  相似文献   

16.
The need for peroxidase purification is stressed as a requirement for comparative studies on isoenzyme structure as well as for detailed investigations on biosynthesis. A single cationic protein possessing the major peroxidase activity was isolated from the medium in which peanut cells had grown. The antibodies raised against this pure protein were employed as a probe to study the site of synthesis of peroxidase in the cell as well as the proportion of total synthesized protein which was peroxidase. Structural studies on the purified isoenzymes suggest the presence of three gene loci for peroxidase in cultured peanut cells. The results are discussed together with potential assays for induction of this enzyme and the relationship to cell development.  相似文献   

17.
Haldane's laws, which apply to situations in which CO and O2 compete for the four heme sites of hemoglobin, are discussed in general statistical mechanical terms. Necessary and sufficient conditions for the validity of Haldane's laws are presented and discussed for general situations in which two ligands compete for interacting active sites on a molecule. Our considerations therefore apply to a competing substrate-inhibitor-allosteric enzyme system for example, as well as to hemoglobin. A generalization of the Monod-Wyman-Changeux model for competing ligands is briefly discussed.  相似文献   

18.
Escherichia coli alkA mutants, which are deficient for an inducible DNA glycosylase, 3-methyladenine-DNA glycosylase II, are sensitive to mutagenesis by low doses of the alkylating agent N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). As many as 90% of the alkA-dependent mutations induced by MNNG are also umuC+ dependent and thus are due to DNA lesions that are substrates for the mutagenic functions of the SOS response. A great number of these mutations are base substitutions at A . T sites, particularly A . T transversions. We discuss which DNA lesions may be responsible for these mutations. Our results show that the induction of 3-methyladenine-DNA glycosylase II, which occurs as part of the adaptive response to alkylating agents such as MNNG, significantly reduces the mutagenicity as well as the lethality of alkylation damage.  相似文献   

19.
Parkinson’s disease (PD) is a progressive neurodegenerative disease characterized in part by the deterioration of dopaminergic neurons which leads to motor impairment. Although there is no cure for PD, the motor symptoms can be treated using dopamine replacement therapies including the dopamine precursor L-DOPA, which has been in use since the 1960s. However, neurodegeneration in PD is not limited to dopaminergic neurons, and many patients experience non-motor symptoms including cognitive impairment or neuropsychiatric disturbances, for which there are limited treatment options. Moreover, there are currently no treatments able to alter the progression of neurodegeneration. There are many therapeutic strategies being investigated for PD, including alternatives to L-DOPA for the treatment of motor impairment, symptomatic treatments for non-motor symptoms, and neuroprotective or disease-modifying agents. G protein-coupled receptors (GPCRs), which include the dopamine receptors, are highly druggable cell surface proteins which can regulate numerous intracellular signaling pathways and thereby modulate the function of neuronal circuits affected by PD. This review will describe the treatment strategies being investigated for PD that target GPCRs and their downstream signaling mechanisms. First, we discuss new developments in dopaminergic agents for alleviating PD motor impairment, the role of dopamine receptors in L-DOPA induced dyskinesia, as well as agents targeting non-dopamine GPCRs which could augment or replace traditional dopaminergic treatments. We then discuss GPCRs as prospective treatments for neuropsychiatric and cognitive symptoms in PD. Finally, we discuss the evidence pertaining to ghrelin receptors, β-adrenergic receptors, angiotensin receptors and glucagon-like peptide 1 receptors, which have been proposed as disease modifying targets with potential neuroprotective effects in PD.  相似文献   

20.
Martin Fotta 《Ethnos》2013,78(5):806-827
The community life of Calon Romanies (Gypsies) in Bahia, northeast Brazil, is politically instituted through and by violence. Violence and fear of violence underlie Calon sociability and serve as a way to mark Calon as distinct from Jurons (non-Gypsies). Within communities, it undermines the tendency for personal power and efficacy to coalesce into rank, as well as the tendency for settlements to petrify into entities with fixed identities. Ultimately, the article argues, what makes violence practicable as a mode of fabricating social relations in the first place is Calon non-sedentarism, which posits one’s readiness to move as a mechanism through which belonging and relatedness are expressed, and which values flexibility in spatial arrangements rather than a fixed domicile.  相似文献   

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