415 research outputs found
Isolation of oligomycin-sensitive adenosine triphosphatase from beef heart mitochondria and analysis of its fine structure
1. An oligomycin -sensitive ATPase was isolated and partially purified from beef heart mitochondria. The specific activity of ATPase sensitive to oligomycin
of the fraction was five to eight times that of aged mitochondrial or of DNP-induced mitochondrial ATPase assayed under the same condition. 2. Electron micrographs of the partially purified oligomycin- sensitive ATPase
reveal a structure in which headpieces are regularly attached by way of stalks to a thread-like structure derived from a superficial portion of base pieces. 3. A high concentration of the structured material coincided with a high activity of oligomycin-sensitive ATPase. When the headpieces were detached from the structure, the ATPase became insensitive to oligomycin. 4. The fraction of oligomycin -sensitive ATPase was essentially free of membrane structure and was contaminated with a small amount of cytochromes b and Cl but no cyt. a. Cytochrome concentrations of the preparations were indifferent to the activity of oligomycin sensitive ATPase. It follows that ATPase does not require cytochromes or membrane structure for its oligomycin sensitivity. 5. From these results it seems that the factor rendering ATPase sensitive to oligomycin should be contained in the stalks and/or the thread-like portion of basepieces of the structure. The structure is the simplest unit of oligomycinsensitive
ATPase as yet obtained. 6. The structure was called "oligomycin-sensitive ATPase particles" (abbreviated
as OSA particles). A unit of OSA particles consists of a headpiece attached by a stalk to a portion of base piece.</p
Leukemia autopsies in Japan
For the purpose to know whether the annual increase of leukemia incidence in Japan is due to some leukemogenic factors or due to the increased detection
rate, the authors made some statistical survey of autopsy cases in which the
diagnosis is reliable and not any type of leukemias escape the detection. The
results showed that acute leukemias, which are found mostly in younger age, is
actually increasing. In addition, it has been deduced that among the suspected
factors the increase in ionizing radiation will be one of the most probable factors
for the increase in leukemia incidence</p
A developmental study of violence-related problematic behaviors (2)
The purpose of this study was to compare children's and parents' normative consciousness with respect to the multiple problematic behaviors in the three age groups of children. The first age group consisted of elementary school children from fourth- to sixth-graders (N=285) and their parents (N=254). The second age group consisted of junior high school students from first- to third-graders (N=270) and their parents (N=245). The third age group consisted of high school students from first- to third-graders (N=274) and their parents (N=233). Normative consciousness was measured with 49 items in eleven subscales of problematic behaviors. Each item was rated on a 4-point scale indicating how severely children were punished, from not at all (1) to very much (4). Children rated the extent to which they would receive punishment from their parents if they would do each problematic behavior. Parents rated the extent to which they would give punishment to their child if their child would do each problematic behavior. The main results were as follows. Children's ratings generally declined with age, especially the third age group's ratings declined drastically. Parents' ratings on the five subscales of bullying, defiant attitude, fashion, disturbance of activities in a class, and drinking and smoking declined with age of children. However, parents' ratings on the other six subscales of violence, shoplifting and use without permission, undisciplined school life, undisciplined home life, delinquency, and schoolgirl's compensated dating did not change as a function of children's age. These findings were discussed in relation to the prevalence and the seriousness of problematic behaviors
Identification of a second gene associated with variation in vertebral number in domestic pigs
<p>Abstract</p> <p>Background</p> <p>The number of vertebrae in pigs varies and is associated with body size. Wild boars have 19 vertebrae, but European commercial breeds for pork production have 20 to 23 vertebrae. We previously identified two quantitative trait loci (QTLs) for number of vertebrae on <it>Sus scrofa </it>chromosomes (SSC) 1 and 7, and reported that an orphan nuclear receptor, <it>NR6A1</it>, was located at the QTL on SSC1. At the <it>NR6A1 </it>locus, wild boars and Asian local breed pigs had the wild-type allele and European commercial-breed pigs had an allele associated with increased numbers of vertebrae (number-increase allele).</p> <p>Results</p> <p>Here, we performed a map-based study to define the other QTL, on SSC7, for which we detected genetic diversity in European commercial breeds. Haplotype analysis with microsatellite markers revealed a 41-kb conserved region within all the number-increase alleles in the present study. We also developed single nucleotide polymorphisms (SNPs) in the 450-kb region around the QTL and used them for a linkage disequilibrium analysis and an association study in 199 independent animals. Three haplotype blocks were detected, and SNPs in the 41-kb region presented the highest associations with the number of vertebrae. This region encodes an uncharacterized hypothetical protein that is not a member of any other known gene family. Orthologs appear to exist not only in mammals but also birds and fish. This gene, which we have named <it>vertnin </it>(<it>VRTN</it>) is a candidate for the gene associated with variation in vertebral number. In pigs, the number-increase allele was expressed more abundantly than the wild-type allele in embryos. Among candidate polymorphisms, there is an insertion of a SINE element (PRE1) into the intron of the Q allele as well as the SNPs in the promoter region.</p> <p>Conclusions</p> <p>Genetic diversity of <it>VRTN </it>is the suspected cause of the heterogeneity of the number of vertebrae in commercial-breed pigs, so the polymorphism information should be directly useful for assessing the genetic ability of individual animals. The number-increase allele of swine <it>VRTN </it>was suggested to add an additional thoracic segment to the animal. Functional analysis of <it>VRTN </it>may provide novel findings in the areas of developmental biology.</p
Inverse square Levy walk emerging universally in goal-oriented tasks
The Levy walk in which the frequency of occurrence of step lengths follows a
power-law distribution, can be observed in the migratory behavior of organisms
at various levels. Levy walks with power exponents close to 2 are observed, and
the reasons are unclear. This study aims to propose a model that universally
generates inverse square Levy walks (called Cauchy walks) and to identify the
conditions under which Cauchy walks appear. We demonstrate that Cauchy walks
emerge universally in goal-oriented tasks. We use the term "goal-oriented" when
the goal is clear, but this can be achieved in different ways, which cannot be
uniquely determined. We performed a simulation in which an agent observed the
data generated from a probability distribution in a two-dimensional space and
successively estimated the central coordinates of that probability
distribution. The agent has a model of probability distribution as a hypothesis
for data-generating distribution and can modify the model such that each time a
data point is observed, thereby increasing the estimated probability of
occurrence of the observed data. To achieve this, the center coordinates of the
model must be moved closer to those of the observed data. However, in the case
of a two-dimensional space, arbitrariness arises in the direction of correction
of the center; this task is goal oriented. We analyze two cases: a strategy
that allocates the amount of modification randomly in the x- and y-directions,
and a strategy that determines allocation such that movement is minimized. The
results reveal that when a random strategy is used, the Cauchy walk appears.
When the minimum strategy is used, the Brownian walk appears. The presence or
absence of the constraint of minimizing the amount of movement may be a factor
that causes the difference between Brownian and Levy walks
Multimodality imaging of biatrial myxomas in an asymptomatic patient
AbstractMyxomas are located in the left atrium in 75–80% of cases and almost always present with signs and symptoms of a thromboembolic event. Biatrial myxomas are rare, and their incidence is generally less than 2.5% of all myxomas. We herein present a case of biatrial myxomas as an incidental finding by echocardiography where the patient underwent surgery. Echocardiography continues to be the initial imaging modality for intracardiac masses. Cardiac magnetic resonance provides superior tissue characterization, particularly important in differentiating a myxoma from a thrombus. Appropriate use of these non-invasive imaging modalities may lead to a correct diagnosis and good outcome.<Learning objective: In this report we present a rare case of cardiac biatrial myxomas. Multimodality imaging, especially delayed enhancement cardiac magnetic resonance imaging, provided specific findings for the diagnosis.
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