Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A brief overview on thermogenic mechanisms in young precocial birds is given. While shivering thermogenesis is well documented in these birds, evidence for a facultative non-shivering component of heat production, comparable to that found in the brown adipose tissue of mammals, is ambiguous. One reason for this is the confusion between thermoregulatory and obligatory thermogenesis. In particular, the existence of a thermogenic reaction, even a futile one, does not by itself constitute proof of true thermoregulatory non-shivering thermogenesis. More probably, such a reaction is another obligatory component of heat production. Heat increment of feeding and motor activity are classical examples of such mechanisms. Thermogenesis arising from such mechanisms can often be adaptively used by the thermoregulatory systems in young birds, as well as in adults.
Comp Biochem Physiol A Mol Integr Physiol 2002 Apr
PMID:Facultative and obligatory thermogenesis in young birds: a cautionary note. 1189 84

The development of reliable and accurate devices for the correction of nonuniform soft tissue attenuation is essential for the future clinical use of SPET myocardial perfusion imaging. In addition to abolishing false-positive defects, which is the chief goal, such corrected SPET images may allow for improved detection of coronary artery disease and perhaps ultimately for true quantification of regional myocardial blood flow. Although progress has been made, most existing attenuation correction devices are not yet ready for prime time. To date the literature shows as many positive results as negative results. There is considerable uncertainty, confusion, and skepticism about the true reliability and value of currently available attenuation correction packages. Although commonly referred to as "attenuation correction devices," these packages are in fact much more complex systems and contain novel mechanical designs, novel image acquisition and image reconstruction algorithms, scatter correction, and depth-dependent resolution compensation, in addition to attenuation correction. Each of these variables needs to be better understood and tested prior to clinical implementation. Although the general concepts are shared, there are as may different approaches to attenuation correction as there are vendors. In order to minimize the confusion of potential buyers about such complex systems, it is desirable that, before attenuation correction is implemented in routine clinical practice, each attenuation correction device is rigorously tested using a standardized testing protocol. Potential buyers of equipment should be able to compare the results of testing with various devices against predefined criteria in order to make an educated decision. Such standards have as yet not been developed. At the present time it is unclear whether attenuation correction of cardiac SPET will remain the emperor's new clothes or will develop into a fashionable Armani suit. Until further progress has been made, one cannot recommend attenuation correction devices for routine clinical practice.
Eur J Nucl Med Mol Imaging 2002 Mar
PMID:Should SPET attenuation correction be more widely employed in routine clinical practice? Against. 1200 18

Examination of genetic and ecological relationships within sibling species complexes can provide insights into species diversity and speciation processes. Alpheus angulatus and A. armillatus, two snapping shrimp species with overlapping ranges in the north-western Atlantic, are similar in morphology, exploit similar ecological niches and appear to represent recently diverged sibling species. We examined phylogenetic and ecological relationships between these two species with: (i) sequence data from two mitochondrial genes (16S rRNA and COI); (ii) data on potential differences in microhabitat distribution for A. armillatus and A. angulatus; and (iii) data from laboratory experiments on the level of reproductive isolation between the two species. DNA sequence data suggest A. armillatus and A. angulatus are sister species that diverged subsequent to the close of the Isthmus of Panama, and that haplotype diversity is lower in A. armillatus than in A. angulatus. Both species are distantly related to A. heterochaelis and A. estuariensis, two species with which A. angulatus shares some similarities in coloration. Ecological data on the distribution of A. angulatus and A. armillatus from two locations revealed differences in distribution of the two species between habitat patches, with each patch dominated by one or the other species. However, there was no apparent difference in distribution of the two species within habitat patches with respect to microhabitat location. Ecological data also revealed that heterospecific individuals often occur in close proximity (i.e. within metres or centimetres) where sympatric. Behavioural data indicated that these species are reproductively isolated, which is consistent with speciation in transient allopatry followed by post-divergence secondary contact. Our data further resolve taxonomic confusion between the sibling species, A. armillatus and A. angulatus, and suggest that sympatry in areas of range overlap and exploitation of similar ecological niches by these two recently diverged species have selected for high levels of behavioural incompatibility.
Mol Ecol 2002 Aug
PMID:Genetic, ecological, and behavioural divergence between two sibling snapping shrimp species (Crustacea: Decapoda: Alpheus). 1214 63

Carriers of X-linked ornithine transcarbamylase deficiency (OTCD) are themselves mildly affected. The allopurinol test is quite sensitive (92.7%) and very specific in detecting these carriers. Consequently, it has also been recommended for the diagnosis of mild OTCD in the general population. However, there is a controversy on its utility since OTCD could not be demonstrated in several patients with positive test results but negative family histories. We show that this controversy is due to an improper use of statistical concepts, i.e., to the postulate of a specificity of "100%," and to the confusion of specificity with type I error rate. Spontaneous orotic aciduria implies a positive allopurinol test and limits the specificity of the test to a maximum of 99.7%. Therefore, according to Bayes' theorem, almost all positive test results in the general population must turn out to be type I errors, due to the minute prevalence (1/32,000) of mild OTCD (i.e., asymptomatic carriers and male patients with inapparent disease). Family history seems to be the only preselective parameter that can sufficiently raise the prevalence in the group to be tested. Bayesian analysis also yields the rate of type II errors (OTCD inspite of a negative test) which is high in closely related at-risk females (22.6% in mothers of male patients) but minimal in the general population. Conclusion. The allopurinol test is useful for the exclusion but not for the diagnosis of inapparent OTCD in sporadic individuals. Test results in possible carriers should be interpreted with caution.
Mol Genet Metab 2002 May
PMID:Remark on utility and error rates of the allopurinol test in detecting mild ornithine transcarbamylase deficiency. 1217 84

Epistasis, the interaction between genes, is a topic of current interest in molecular and quantitative genetics. A large amount of research has been devoted to the detection and investigation of epistatic interactions. However, there has been much confusion in the literature over definitions and interpretations of epistasis. In this review, we provide a historical background to the study of epistatic interaction effects and point out the differences between a number of commonly used definitions of epistasis. A brief survey of some methods for detecting epistasis in humans is given. We note that the degree to which statistical tests of epistasis can elucidate underlying biological interactions may be more limited than previously assumed.
Hum Mol Genet 2002 Oct 01
PMID:Epistasis: what it means, what it doesn't mean, and statistical methods to detect it in humans. 1235 82

One of the claims of reductionism is that it can explain all the features of living systems by an analysis of their physico-chemical constituents. Such a claim disregards the existence in biological systems of emergent properties that do not exist in their isolated components but which allow autonomous organisms to be directively organized in a self-regulated and integrated manner. It is not possible to describe biological systems adequately without using functional language that is meaningless in the physical sciences. The description of biological functions is also an essential part of immunology and functional explanations are more useful than causal explanations also in this discipline. Since causality is not a relation between a material object and an event, the structure of an antibody cannot be the cause of its binding activity. When structure-function relationships are analysed, the search should be for correlations rather than for causal relations. Methods used to find correlations between the atomic structure of antibody binding sites and their binding activity are mostly based on mutagenesis studies. Since the effect of any mutation depends on the molecular context, it is usually very difficult to predict the effects of multiple mutations on antibody function. Our knowledge of the molecular basis of antigen-antibody recognition has led to the expectation that it may be possible to develop new vaccines using molecular design principles. Such unwarranted hopes arise because of a confusion between antigenicity and immunogenicity. Although knowledge of antibody structure is of little use in vaccine design, it may help to develop therapeutic inhibitors and antibodies effective in the passive immunotherapy of viral infection.
J Mol Recognit
PMID:Reductionism and the search for structure-function relationships in antibody molecules. 1244

The sequencing of a genome is the first stage of its complete characterization. Subsequent work seeks to utilize available sequence data to gain a better understanding of the genes which are found within a genome. Gene families comprise large portions of the genomes of higher vertebrates, and the available genomic data allow for a reappraisal of gene family evolution. This reappraisal will clarify relatedness within and between gene families. One such family, the alpha-actinin gene family, is part of the spectrin superfamily. There are four known loci, which encode alpha-actinins 1, 2, 3, and 4. Of the eight domains in alpha-actinin, the actin-binding domain is the most highly conserved. Here we present evidence gained through phylogenetic analyses of the highly conserved actin-binding domain that alpha-actinin 2 was the first of the four alpha-actinins to arise by gene duplication, followed by the divergence of alpha-actinin 3 and then alpha-actinins 1 and 4. Resolution of the gene tree for this gene family has allowed us to reclassify several alpha-actinins which were previously given names inconsistent with the most widely accepted nomenclature for this gene family. This reclassification clarifies previous discrepancies in the public databases as well as in the literature, thus eliminating confusion caused by continued misclassification of members of the alpha-actinin gene family. In addition, the topology found for this gene family undermines the 2R hypothesis theory of two rounds of genome duplication early in vertebrate evolution.
J Mol Evol 2003 Jan
PMID:The alpha-actinin gene family: a revised classification. 1256 17

A proposal is put forth to unify the nomenclature of the CCN family of secreted, cysteine rich regulatory proteins. In the order of their description in the literature, CCN1 (CYR61), CCN2 (CTGF), CCN3 (NOV), CCN4 (WISP-1), CCN5 (WISP-2), and CCN6 (WISP-3) constitute a family of matricellular proteins that regulate cell adhesion, migration, proliferation, survival, and differentiation, at least in part through integrin mediated mechanisms. This proposal is endorsed by the International CCN Society and will serve to eliminate confusion from the multiple names that have been given to these molecules.
Mol Pathol 2003 Apr
PMID:Proposal for a unified CCN nomenclature. 1266 31

The Charadriiformes is a large and diverse order of shorebirds currently classified into 19 families, including morphologically aberrant forms that are of uncertain phylogenetic placement within non-passerine birds in general. Recent attempts using morphological characters have failed to recover a well-supported phylogeny depicting higher level relationships within Charadriiformes and the limits to the order, primarily because of inconsistency and homoplasy in these data. Moreover, these trees are incongruent with the relationships presented in the DNA hybridization tapestry of, including the location of the root and the branching order of major clades within the shorebirds. To help clarify this systematic confusion we therefore sequenced the large RAG-1 nuclear exon (2850 bp) from 36 species representing 17 families of shorebirds for which DNA was available. Trees built with maximum parsimony, maximum likelihood or Bayesian methods are topologically identical and fully resolved, with high support at basal nodes. This further attests to the phylogenetic utility of the RAG-1 sequences at higher taxonomic levels within birds. The RAG-1 tree is topologically similar to the DNA hybridization tree in depicting three major subordinal clades of shorebirds, the Charadrii (thick-knees, sheathbills, plovers, oystercatchers, and allies), Scolopaci (sandpipers and jacanas) and the Lari (coursers, pratincoles, gulls, terns, skimmers, and skuas). However, the basal split in the RAG-1 tree is between Charadrii and (Scolopaci+Lari), whereas in the DNA hybridization tree Scolopaci is the sister group to the (Charadrii+Lari). Thus in both of these DNA-based trees the Alcidae (auks, murres, and allies) are not basal among shorebirds as hypothesized in morphological trees, but instead are placed as a tip clade within Lari. The enigmatic buttonquails (Turnicidae), variously hypothesized as being allied to either the Galliformes, Gruiformes, or Charadriiformes, are shown to be a basal lineage in the more conventional Lari clade. Divergence times estimated with rate-smoothing methods and minimum time constraints imposed at nodes with key fossils suggest that Charadriiformes originated in Gondwanaland.
Mol Phylogenet Evol 2003 Nov
PMID:RAG-1 sequences resolve phylogenetic relationships within Charadriiform birds. 1367 82

To date, the nomenclature of mammalian genes encoding the numerous subunits and their many isoforms that comprise the family of vacuolar H(+)-ATPases has not been systematic, resulting in confusion both in the literature and among investigators. We present the official new system for these genes, approved by both Human and Mouse Gene Nomenclature Committees.
Mol Cell 2003 Oct
PMID:Revised nomenclature for mammalian vacuolar-type H+ -ATPase subunit genes. 1458 Mar 32


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>