SEARCH · Search PubMed
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
The understanding of life on Earth that we have obtained from the science of evolutionary biology offers clues to the qustion of what life might be like if found elsewhere. After presenting the basics of the evolutionary process, I discuss the factors that determine the outcome of evolution, the role of key innovations and extinction in evolution, and whether the evolution of human life is inevitable.
INTRODUCTION: Contrary to patients exhibiting cellular immunodepression, legionellosis is rare in HIV-infected patients. We report 4 cases. OBSERVATIONS: Four men aged 41 to 48 were infected by HIV-1. Three of them were treated with antiretroviral therapy. The clinical and biological manifestations were unspecific. Evolution was favourable with adapted antibiotic therapy (erythromycine for three patients and ciprofloxacine for the fourth). COMMENTS: Legionella pneumophila serotype Lp1 remains the principle etiological agent. Frequent use of contrimoxazole in prophylaxis against pneumocystosis and toxoplasmosis, macrolides, rifamycines and fluoroquinolones in the preventive and curative treatment of mycobacterioses, and the relative conservation of monocyte/macrophage function and immune repair with efficient antiretroviral therapy, may explain the low prevalence of this disease in HIV infections.
The spectrin superfamily (spectrin, alpha-actinin, utrophin and dystrophin) has in common a triple helical repeating unit of ~106 amino acid residues. In spectrin, alpha and beta chains contain multiple copies of this repeat. beta-spectrin chains contain the majority of binding activities in spectrin and are essential for animal life. Canonical beta-spectrins have 17 repeats; beta-heavy spectrins have 30. Here, the repeats of five human beta-spectrins, plus beta-spectrins from several other vertebrates and invertebrates, have been analysed. Repeats 1, 2, 14 and 17 in canonical beta are highly conserved between invertebrates and vertebrates, and repeat 8 in some isoforms. This is consistent with conservation of critical functions, since repeats 1, 2 and 17 bind alpha-spectrin. Repeats 1 of beta-spectrins are not always detected by SMART or Pfam tools. A profile hidden Markov model of beta-spectrin repeat 1 detects alpha-actinins, but not utrophin or dystrophin. Novel examples of repeat 1 were detected in the spectraplakins MACF1, BPAG1 and plectin close to the actin-binding domain. Ankyrin binds to the C-terminal portion of repeat 14; the high conservation of this entire repeat may point to additional, undiscovered ligand-binding activities. This analysis indicates that the basic triple helical repeat pattern was adapted early in the evolution of the spectrin superfamily to encompass essential binding activities, which characterise individual repeats in proteins extant today.
IMGT, the international ImMunoGeneTics information system(R) (http://imgt.cines.fr), is a high quality integrated knowledge resource specializing in immunoglobulins (IG), T cell receptors (TR), major histocompatibility complex (MHC) and related proteins of the immune system (RPI) of human and other vertebrates, created in 1989, by the Laboratoire d'ImmunoGenetique Moleculaire LIGM. IMGT provides a common access to standardized data which include nucleotide and protein sequences, oligonucleotide primers, gene maps, genetic polymorphisms, specificities, 2D and 3D structures. IMGT consists of several sequence databases (IMGT/LIGM-DB, IMGT/MHC-DB, IMGT/PRIMER-DB), one genome database (IMGT/GENE-DB) and one three-dimensional structure database (IMGT/3Dstructure-DB), interactive tools for sequence analysis (IMGT/V-QUEST, IMGT/JunctionAnalysis, IMGT/PhyloGene, IMGT/Allele-Align), for genome analysis (IMGT/GeneSearch, IMGT/GeneView, IMGT/LocusView) and for 3D structure analysis (IMGT/StructuralQuery), and Web resources ("IMGT Marie-Paule page") comprising 8000 HTML pages. IMGT other accesses include SRS, FTP, search by BLAST, etc. By its high quality and its easy data distribution, IMGT has important implications in medical research (repertoire in autoimmune diseases, AIDS, leukemias, lymphomas, myelomas), veterinary research, genome diversity and genome evolution studies of the adaptive immune responses, biotechnology related to antibody engineering (scFv, phage displays, combinatorial libraries) and therapeutical approaches (grafts, immunotherapy). IMGT is freely available at http://imgt.cines.fr.
The present paper is devoted to the evolutionary role of genetic modules shuffing. The mechanisms capable to produce new molecular functions and significant complications of ontogenesis are reviewed. Two-step model of macroevolution is proposed. This model comprises: (1) Arising of a new combination of genetic modules. This step does not result in formation of a new taxon but makes necessary ground for that process. (2) Precise structure completing of the new combination of modules and corresponding genome optimization by use of various mechanisms including point mutations. This step concerns many genes and finally leads to formation of a new taxon. It is shown that arising of new combinations of genetic modules might work out as molecular basis for progressive evolution, while alternative structural completing of the same combination might result in adaptive radiation.
IMGT, the international ImMunoGeneTics information system (http://imgt.cines.fr), was created in 1989 at Montpellier, France. IMGT is a high quality integrated knowledge resource specialized in immunoglobulins (IG), T cell receptors (TR), major histocompatibility complex (MHC) of human and other vertebrates, and related proteins of the immune system (RPI) which belong to the immunoglobulin superfamily (IgSF) and MHC superfamily (MhcSF). IMGT provides a common access to standardized data from genome, proteome, genetics and three-dimensional structures. The accuracy and the consistency of IMGT data are based on IMGT-ONTOLOGY, a semantic specification of terms to be used in immunogenetics and immunoinformatics. IMGT-ONTOLOGY has been formalized using XML Schema (IMGT-ML) for interoperability with other information systems. We are developing Web services to automatically query IMGT databases and tools. This is the first step towards IMGT-Choreography which will trigger and coordinate dynamic interactions between IMGT Web services to process complex significant biological and clinical requests. IMGT-Choreography will further increase the IMGT leadership in immunogenetics and immunoinformatics for medical research (repertoire analysis of the IG antibody sites and of the TR recognition sites in autoimmune and infectious diseases, AIDS, leukemias, lymphomas, myelomas), veterinary research (IG and TR repertoires in farm and wild life species), genome diversity and genome evolution studies of the adaptive immune responses, biotechnology related to antibody engineering (single chain Fragment variable (scFv), phage displays, combinatorial libraries, chimeric, humanized and human antibodies), diagnostics (detection and follow up of residual diseases) and therapeutical approaches (grafts, immunotherapy, vaccinology). IMGT is freely available at http://imgt.cines.fr.
Analysis of the taxonomic position of most species and forms of the char (genus Salvelinus, Salmonidae: Teleostei) was made based on RAPD-PCR. The material was represented by samples from 29 populations from the Kuril Islands, coast of the Sea of Okhotsk, Kamchatka, Chukotka, Taymyr, Transbaikalia, the Kola Peninsula, Svalbard, Finland, and North America. It was shown that the genus Salvelinus splits into three well-justified clusters: (1) all the forms assigned to the Salvelinus alpinus--S. malma complex; (2) two samples of the White-Spotted Char from the Southern Kuril Islands and from Kamchatka; (3) two North American species, S. fontinalis and S. namaycush (samples of the North American species S. confluentis were absent from the collection). Analysis of the absolute values of genetic disctances of the S. alpinus--S. malma forms relative to S. leucomaenis, S. fontinalis, and S. namaycush revealed distances approaching the species rank between the following isolates: Frolikh Char, Mountain Char, Black Lake Char, Goggle-Eyed Char, and Neyva Char. Samples of Dolly Varden currently considered as "S. malma", do not constitute a separate cluster, falling within the group of the Arctic char S. alpinus. This conclusion is supported by the analysis of the results of three series of experiments by R. Phillips on ITS1 ribosome genes (Pleute et al., 1992; Phillips et al., 1995; Phillips et al., 1999). This indicates the infraspecific rank of malma within S. alpinus. Isolated populations of "Salvethymus svetovidovi" from the lake Elgygytgyn (Chukotka Peninsula) and of the char from the lake Chyornoye (Onekotan Island), recently described as S. gritzenkoi (Vasil'eva, Stygar, 2000), fell withing the S. alpinus--S. malma complex, the Onekotan char grouped together with another isolate from the same island. Comparison of genetic distances between the samples showed that the differences between the two isolated of Onekotan and migratory forms of the Kuril Islands are approximately equal, yet the homogeneity of the Chyornoye sample is higher than that of the other samples. The revealed 330-nucleotide diagnostic sequence of the Onekotan lake isolate showed identity of part of the fragment with a section of expressed DNA from the library of EST clones derived from the gills of Salmo salar, this possibly indicates the adaptive character of the evolution.
Early works by Altukhov and his associates on pine and spruce laid the foundation for Russian population genetic studies on tree species with the use of molecular genetic markers. In recent years, these species have become especially popular as nontraditional eukaryotic models for population and evolutionary genomic research. Tree species with large, cross-pollinating native populations, high genetic and phenotypic variation, growing in diverse environments and affected by environmental changes during hundreds of years of their individual development, are an ideal model for studying the molecular genetic basis of adaptation. The great advance in this field is due to the rapid development of population genomics in the last few years. In the broad sense, population genomics is a novel, fast-developing discipline, combining traditional population genetic approaches with the genomic level of analysis. Thousands of genes with known function and sometimes known genomic localization can be simultaneously studied in many individuals. This opens new prospects for obtaining statistical estimates for a great number of genes and segregating elements. Mating system, gene exchange, reproductive population size, population disequilibrium, interaction among populations, and many other traditional problems of population genetics can be now studied using data on variation in many genes. Moreover, population genomic analysis allows one to distinguish factors that affect individual genes, alleles, or nucleotides (such as, for example, natural selection) from factors affecting the entire genome (e.g., demography). This paper presents a brief review of traditional methods of studying genetic variation in forest tree species and introduces a new, integrated population genomics approach. The main stages of the latter are : (1) selection of genes, which are tentatively involved in variation of adaptive traits, by means of a detailed examination of the regulation and the expression of individual genes and genotypes, with subsequent determination of their complete allelic composition by direct nucleotide sequencing; (2) examination of the phenotypic effects of individual alleles by, e.g., association mapping; and (3) determining the frequencies of the selected alleles in natural population for identification of the adaptive variation pattern in the heterogeneous environment. Through decoding the phenotypic effects of individual alleles and identification of adaptive variation patterns at the population level, population genomics in the future will serve as a very helpful, efficient, and economical tool, essential for developing a correct strategy for conserving and increasing forests and other commercially valuable plant and animal species.
The enterotoxins and the toxic-shock-syndrome toxin-1 of Staphylococcus aureus, the erythrogenic toxins of Streptococcus pyogenes as well as a still uncharacterized exoprotein of Mycoplasma arthritidis belong to a family of exotoxins, that have in common a potent mitogenic activity for T lymphocytes of several species. These proteins stimulate CD4(+)- and CD8+ T-lymphocytes by cross-linking the T-cell-antigen receptor with MHC-class-II molecules on accessory or target cells. They are functionally bivalent molecules having distinct interaction sites for variable parts of the T-cell receptor and for nonpolymorphic parts of MHC-class-II molecules. Due to their preferential action on T cells expressing certain V beta-parts of the T-cell receptor the designation "superantigens" has been proposed. The mechanism of T-cell stimulation has apparently been conserved in evolution and has been adapted to the host's T-cell-receptor repertoire. The T cells stimulating activity apparently contributes to the pathogenesis of certain infectious diseases. Noteworthy, mice express endogenous "superantigens" that have similar properties.
Explore the source record for details and available documents.
While a single patient's addiction arises from a pattern of individual factors there appears to be a general cultural climate fostering its genesis in many variants. In the present contribution the metamorphosis of the metaparadigm from the dialectic to the dialogue is characterized as cultural transition-time demanding from the individual to cope and live with permanent contradictions and conflicts. On the background of this anthropologic situation addiction is understood as internalized foreign determination sustaining a common though antiquated scheme of psychic and social conflict conditioned by outdated patterns of education and socialisation. Addiction is appreciated as an inadequate attempt of the individual and of society toward adaptation, based on historic evolution of culture.
The methodology used in Phylogenetics remains one of the more interesting problems in comparative biology. Among the methods used, the cladistic is the most accurate. In the present case, among the Saurians, the characters chosen appeared early and cannot be referred to any adaptation bound to an evolutive progress. We have successively considered their distribution in the classification, their polarity and one phylogenetic hypothesis based on the Hennig's concepts. Such a work leads necessarily to systematical conclusions. For instance, we note the heterogeneity of some families. Among the Iguania, the Iguanidea are polyphyletics, the north-american forms breaking up from the other very early. Among the Scincomorpha, the Lacertilia result from two parts of different origins. This research verifies some systematic cuttings in the modern classification: among the Anguimorpha, the separation between Helodermatidea and the group, Varanidea-Lanthanotidea. The characters studied show a non-random distribution in the classification and show also some consistency with the geographical distribution of the extant Saurians. Therefore, it is important to search for the most parsimonious geographical hypothesis, which is in concern with the present data on the continental drift and generally on the history of the Earth, and which strengthens the cladograms posed from the selected characters.
The following ultrastructural formations are found in the bacteria of various infections: fibrillar and drop-like microcapsules, an increase of nucleotide size and number, micropyles. The dynamics of staphylococcus L-form formation in sepsis as well as the phenomenon of incomplete phagocytosis and endocytobiosis were studied. The latter is observed in mixed infection: dysentery bacteria lamblia, gonococci and trichomonas. These alterations indicate increased bacterial pathogenicity and seem to reflect the evolution of the bacteria adaptive mechanisms under the conditions of antibiotic therapy.
Pain is the most common symptom in patients suffering from cancer, in particular for advanced diseases. Unfortunately, one third of the patient do not benefit from optimal pain control. One must stress the importance of defining the etiology of pain and subsequently its pathophysiology. This thorough evaluation can help to formulate a proper strategy for a treatment of pain that could be adapted to the disease evolution. A multidisciplinary approach with respect to the WHO prescribing criteria is the most appropriate way to control severe cancer pain syndromes.
Effects of X-ray low doses (0.5-25 cGy) with following UV light (254 nm, 20 J/m2) on human peripheral blood lymphocytes were studied. Reparation response registered by unscheduled DNA synthesis (UDS) activity was demonstrated to be the most intensive after action of X-rays in dose ranges 2-3 cGy and 15-20 cGy, and least intensive after 10 cGy. In those cells where UV light was followed by X-rays, dose ranges 2-3 cGy and 15-20 cGy cause essential decrease of UDS as compared with UV-light action only. The most intensive UDS was in those UV-irradiated lymphocytes which where previously exposed to 10 cGy of X-rays. At the same time 10 cGy cause minimal reparation response without UV light. Possible mechanisms of discovered phenomena are discussed. In particular, reaction on 2-3 cGy might be a reorganization of genome for adaptive response or an evolution reserve cells response. From 10 cGy the reason of reaction might be a reparation, induced by radiation.
An adaptive model for the evolution of reproductive failure predicted psychosocial stress to increase as anatomic causes of infertility decrease. The nonanatomic infertility group in our study reported greater psychosocial stress than intermediate (P < 0.008) or anatomic groups (P < 0.0005). Controls, women with nonanatomic etiologies who were not attempting pregnancy, also reported higher psychosocial stress than the anatomic group (P < 0.007). Results are consistent with the hypothesis that psychosocial distress contributes significantly to the etiology of some forms of infertility.
Treatment of rheumatoid arthritis must be instituted as early as possible when the diagnosis is established. In the severe forms, a treatment by a trained team allowing pluridisciplinar coping is needed. The general practitioner takes an important place in this team. The treatment of rheumatoid arthritis includes five points: information of patient, medico-psychological approach, local and general treatments, rehabilitation and sometimes surgery. Due to the heterogeneity of rheumatoid arthritis, the therapeutic strategy is adapted according to the evolution, the benefice/risk ratio and the prognostic factors.
To investigate the behaviour of the vasoactive intestinal polypeptide (VIP) in short bowel syndrome (SBS), an experimental model of massive intestinal resection (MIR) was developed. For this purpose, 20 'minipigs' were divided into two experimental groups: A (control) and B (MIR). The parameters determined were the mean plasma levels of VIP and the degree of steatorrhea at four different times: T1 (basal), T2 (one week after surgery), T3 (two weeks after surgery), and T4 (24 weeks after surgery). The results indicated that, after MIR, a progressive decrease in the mean plasma levels of VIP takes place, with statistical significance in T3 (p < 0.05) and T4 (p < 0.01). This situation seems to be a direct result of the massive loss of intestinal tissue, and could lead to the use of this peptide to mark the evolution of the intestinal adaptation process.