Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Minor: Evolution”

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.

At least 73 records · Page 4Linked to original sources
PubMed2003

Envelope diversity, coreceptor usage and syncytium-inducing phenotype of HIV-1 variants in saliva and blood during primary infection.

OBJECTIVE: To determine whether oral fluids can serve as a model for studying HIV-1 shedding, we compared the genetic diversity, coreceptor use, and syncytium-inducing (SI) phenotype of viral variants in saliva and blood during primary HIV-1 infection. DESIGN: Observational cross-sectional cohort study. METHODS: Blood plasma and saliva were sampled from 17 men early in primary HIV-1 infection. Viral diversity, predicted X4/R5 genotype and SI phenotype in samples were determined by heteroduplex tracking assays (HTAs) targeting the V1/V2 and V3 gp120 regions, sequence analyses and MT-2 cell assay. RESULTS: Identical or very similar HTA banding and deduced amino acid sequence patterns in the V1/V2 and V3-encoding regions were observed between paired fluids of each subject. As assessed by V1/V2 HTA, 10 subjects had a single major viral variant and seven subjects exhibited multiple yet highly related variants. Two subjects had V1/V2 variants in blood that were identical to saliva but present in different relative abundances. A sexual transmission pair exhibited genetically dissimilar variants, suggesting transmission of a minor variant or rapid evolution during initial viremia. All subjects harbored R5 non-SI variants. CONCLUSIONS: Relatively homogenous viral populations detected in plasma and saliva prior to seroconversion suggests that HIV-1 is disseminated to oral fluids early in infection and reflects the quasispecies in blood. These findings suggest that the oral cavity may serve as an easily accessible surrogate model for studying the dynamics of HIV-1 shedding at mucosal sites.

Adult↗
PubMed2006

Disassociation between weak sexual isolation and genetic divergence in a hermaphroditic land snail and implications about chirality.

Examination of the association between reproductive isolation and genetic divergence in a variety of organisms is essential for elucidating the mechanisms causing speciation. However, such studies are lacking for hermaphrodites. We measured premating (sexual) isolation in species pairs of the hermaphroditic land snail Albinaria and we compared it with their genetic divergence. We did not find substantial sexual isolation barriers between the species studied. The absence of strong sexual isolation between species implies its minor effect in the evolution of this genus, because distributional, population and life-history characteristics of Albinaria make mate-choice possibly redundant. Furthermore, we found disassociation between genetic divergence and sexual isolation, suggesting that they do not form necessarily a cause-effect duet. However, Albinaria voithii, the only dextral Albinaria species, shows strong sexual isolation against the other sinistral species. We discuss whether change in coiling either has triggered instantaneous speciation, or is an example of character displacement.

Animals↗
PubMed2006

A thick cloud of Neptune Trojans and their colors.

The dynamical and physical properties of asteroids offer one of the few constraints on the formation, evolution, and migration of the giant planets. Trojan asteroids share a planet's semimajor axis but lead or follow it by about 60 degrees near the two triangular Lagrangian points of gravitational equilibrium. Here we report the discovery of a high-inclination Neptune Trojan, 2005 TN(53). This discovery demonstrates that the Neptune Trojan population occupies a thick disk, which is indicative of "freeze-in" capture instead of in situ or collisional formation. The Neptune Trojans appear to have a population that is several times larger than the Jupiter Trojans. Our color measurements show that Neptune Trojans have statistically indistinguishable slightly red colors, which suggests that they had a common formation and evolutionary history and are distinct from the classical Kuiper Belt objects.

Evolution, Planetary↗
PubMed1998

Exclusive and persistent use of the entry coreceptor CXCR4 by human immunodeficiency virus type 1 from a subject homozygous for CCR5 delta32.

Individuals who are homozygous for the 32-bp deletion in the gene coding for the chemokine receptor and major human immunodeficiency virus type 1 (HIV-1) coreceptor CCR5 (CCR5 -/-) lack functional cell surface CCR5 molecules and are relatively resistant to HIV-1 infection. HIV-1 infection in CCR5 -/- individuals, although rare, has been increasingly documented. We now report that the viral quasispecies from one such individual throughout disease is homogenous, T cell line tropic, and phenotypically syncytium inducing (SI); exclusively uses CXCR4; and replicates well in CCR5 -/- primary T cells. The recently discovered coreceptors BOB and Bonzo are not used. Although early and persistent SI variants have been described in longitudinal studies, this is the first demonstration of exclusive and persistent CXCR4 usage. With the caveat that the earliest viruses available from this subject were from approximately 4 years following primary infection, these data suggest that HIV-1 infection can be mediated and persistently maintained by viruses which exclusively utilize CXCR4. The lack of evolution toward the available minor coreceptors in this subject underscores the dominant biological roles of the major coreceptors CCR5 and CXCR4. This and two similar subjects (R. Biti, R. Ffrench, J. Young, B. Bennetts, G. Stewart, and T. Liang, Nat. Med. 3:252-253, 1997; I. Theodoreu, L. Meyer, M. Magierowska, C. Katlama, and C. Rouzioux, Lancet 349:1219-1220, 1997) showed relatively rapid CD4+ T-cell declines despite average or low initial viral RNA load. Since viruses which use CXCR4 exclusively cannot infect macrophages, these data have implications for the relative infection of the T-cell compartment versus the macrophage compartment in vivo and for the development of CCR5-based therapeutics.

Acquired Immunodeficiency Syndrome↗
PubMed1982

Y chromosome duplication in chronic myeloid leukemia.

Y chromosome duplication appeared in a patient with chronic myeloid leukaemia (CML) during blastic crisis. Additional chromosome changes were present. Y chromosome duplication may be a minor route of karyotype evolution in CML.

Adult↗
PubMed2005

Sensitive phenotypic detection of minor drug-resistant human immunodeficiency virus type 1 reverse transcriptase variants.

Detection of drug-resistant variants is important for the clinical management of human immunodeficiency virus type 1 (HIV-1) infection and for studies on the evolution of drug resistance. Here we show that hybrid elements composed of the Saccharomyces cerevisiae retrotransposon Ty1 and the reverse transcriptase (RT) of HIV-1 are useful tools for detecting, monitoring, and isolating drug-resistant reverse transcriptases. This sensitive phenotypic assay is able to detect nonnucleoside reverse transcriptase inhibitor-resistant RT domains derived from mixtures of infectious molecular clones of HIV-1 in plasma and from clinical samples when the variants comprise as little as 0.3 to 1% of the virus population. Our assay can characterize the activities and drug susceptibilities of both known and novel reverse transcriptase variants and should prove useful in studies of the evolution and clinical significance of minor drug-resistant viral variants.

Drug Resistance, Viral↗
PubMed2007

Secondary centers of ossification of the human toes: exceptional polymorphism and evolutionary perspectives.

As great morphological variability characterizes the phalanges of the human toes in adults, we hypothesized for a possible variability in the presence or absence of their secondary (= epiphyseal) centers of ossification linked to the unique morphology of the human foot within primates. The aim of this study was thus to provide original and detailed data on the occurrence of these centers. Classically, the big toe or hallux (I) presents two secondary centers and the lateral toes (II-V) three centers, and consequently the five toes present a total of 14 secondary centers. The material studied consisted of 261 foot radiographs from 261 young individuals of European origin (202 males and 59 females; 6-16 years). The presence (or absence) of the secondary centers of the phalanges of the toes was assessed for each foot. Feet presenting a biphalangeal variant in one or more lateral toes were studied separately. The theoretical possibilities of association of the three secondary centers in a given lateral toe (II-V) are eight in number; these eight patterns were studied and coded in the present study by types A-H. An exceptional variability in the occurrence of the secondary centers in lateral toes (II-V) was observed, and the classic pattern of phalangeal ossification was never observed. The absence of one or more secondary centers seems to be observed only in the human species, and we suggest that this could be a derived pattern specific to the human species, i.e., autapomorphic pattern. These results are of interest in the characterization and understanding of the reduction in size of the lateral toes which characterizes the specific evolution of the human foot.

Adolescent↗
PubMed1992

Intrasexual competition and canine dimorphism in anthropoid primates.

A number of factors, including sexual selection, body weight, body-weight dimorphism, predation, diet, and phylogenetic inertia have been proposed as influences on the evolution of canine dimorphism in anthropoid primates. Although these factors are not mutually exclusive, opinions vary as to which is the most important. The role of sexual selection has been questioned because mating system, which should reflect its strength, poorly predicts variation in canine dimorphism, particularly among polygynous species. Kay et al. (1988) demonstrate that a more refined estimate of intermale competition explains a large proportion of the variation in canine dimorphism in platyrrhine primates. We expand their analysis, developing a more generalized measure of intermale competition based on the frequency and intensity of male-male agonism. We examine the relative influences of predation (inferred by substrate use), female body weight, body-weight dimorphism, diet, and sexual selection on the evolution of anthropoid canine dimorphism. Intermale competition is very strongly associated with canine dimorphism. Predation also has a marked effect on canine dimorphism, in that savanna-dwelling species consistently show greater canine dimorphism than other species, all other factors being held equal. Body-weight dimorphism is also strongly associated with canine dimorphism, though apparently through a common selective basis, rather than through allometric effects. Body weight seems to play only a minor, indirect role in the evolution of canine dimorphism. Diet plays no role. Likewise, we find little evidence that phylogenetic inertia is a constraint on the evolution of canine dimorphism.

Analysis of Variance↗
PubMedDate not supplied

[Human lagochilascariasis. 3 cases encountered in the Federal District, Brazil].

Three new cases of human infection with Lagochilascaris minor are reported. All the patients were from the state of Pará (Brazil), living in rural areas or close to the forest. They were admitted to hospitals in the Federal District due to the presence of abscesses in the region of the neck, ear, mastoid process and, in two of them, to the involvement also of the central nervous system. Microscopic examination of tissue samples taken from the lesions showed sections of eggs and worms--in different evolutive stages--identified as Lagochilascaris minor. Larvae and adult worms obtained from existing fistulae proved also to be of the same species. The three patients were treated with anthelmintic drugs and surgical excision of the lesions, with good clinical results. In two of them, however, relapsing occurred, suggesting that the drugs do not destroy the worm eggs, in spite of the apparent healing of the lesions.

Adolescent↗
PubMedDate not supplied

Fungal rhinosinusitis in patients with chronic sinusal disease.

AIM: Fungal rhinosinusitis in patients with chronic sinusal disease study. In the past decades, there has been an increase in fungal infections, and fungal rhinosinusitis (FRS) has been diagnosed more frequently. Knowing the fungal flora, its prevalence and symptomatic presentation in patients with chronic rhinosinusitis (CRS) will allow a better understanding of this disease, permitting a correct diagnosis, and treatment and formulating its prognosis. STUDY DESIGN: clinical retrospective with transversal cohort. MATERIAL AND METHOD: 62 patients diagnosed with FRS were selected among 890 cases of CRS undergoing endoscopic surgery. We assessed clinical history otolaryngologic examination with nasal videoendoscopy, CT scan, microbiologic and histopatologic tests. RESULTS: The prevalence of FRS was 6.7% and the fungal type most frequently found was the gender Aspergillus. Fungal ball was found in more than half the cases, and allergic fungal rhinosinusitis (AFRS) in more than one third of the patients. Evolution after endoscopic sinus surgery was more favorable in patients with fungus ball, with a minor number of recurrences. CONCLUSIONS: The symptomatic evolution following endoscopic surgery was more favorable in patients with fungal ball, who require a lower number of re-interventions.

Adolescent↗
PubMed2002

Dendritic cell susceptibility to hepatitis C virus genotype 1 infection.

In vitro infection of human monocyte-derived dendritic cells was carried out to study their susceptibility to hepatitis C virus (HCV) infection. Immature dendritic cells and mature dendritic cells were incubated overnight at 37 degrees C with HCV-positive (genotype 1) serum samples; the presence of the viral genome associated with the production of its replicative intermediate was used as evidence of infection. In immature dendritic cells, HCV RNA was detectable from days 1-10 post-infection (p.i.), and de novo synthesis of negative-strand HCV RNA could be demonstrated by a strand-specific rTth reverse transcription-polymerase chain reaction at day 2. In mature dendritic cells, the positive-strand form was detectable from days 1-5 p.i., while the negative-strand HCV RNA appeared at days 1 and 2 p.i. Quasispecies present in the inoculum and 6 days p.i. were analyzed by sequencing hypervariable region 1 of the E2 protein. Only two of seven HVR variants present in the inoculum were found in HCV-infected immature dendritic cells. Another two HVR variants not found in the inoculum were recovered from infected immature dendritic cells, suggesting serum minor variants selection or virus evolution during in vitro replication. Analysis by single-strand conformation polymorphism assay of 5' untranslated region of HCV sequences showed that the patterns obtained from the inoculum and infected immature dendritic cells and mature dendritic cells differed slightly. These findings indicate that both immature dendritic cells and mature dendritic cells are susceptible to HCV genotype 1 infection, supporting at least HCV RNA replication. This model should be a valuable tool for the study of modulation of dendritic cell functions in HCV infection.

Amino Acid Sequence↗
PubMed2002

Generation of RNA aptamers to the G-protein-coupled receptor for neurotensin, NTS-1.

G-protein-coupled receptors (GPCRs) are integral membrane proteins involved in signal transduction and constitute major drug targets for disease therapy. Aptamers, which are globular RNA or DNA molecules evolved to specifically bind a target, could represent a valuable tool with which to probe the role of such receptors in normal tissue and disease pathology and for cocrystallization with receptors for structure determination by X-ray crystallography. Using the bacterially expressed rat neurotensin receptor NTS-1 as an example, we describe a strategy for the generation of GPCR-specific RNA aptamers. Seven rounds of a "subtractive," paramagnetic bead-based selection protocol were used to enrich for neurotensin receptor-specific aptamers, while circumventing the evolution of aptamers reactive to minor protein contaminants. Representatives of each aptamer family were analyzed in Escherichia coli membrane nitrocellulose filter binding assays. Eight aptamers demonstrated specificity for the neurotensin receptor. One aptamer, P19, was characterized in detail and shown to bind to both the rat receptor and the human receptor with nanomolar affinity. P19 was also shown to interact with rat neurotensin receptor expressed in CHO cells, in both membrane preparations and intact cells. P19 represents the first example of a GPCR-specific RNA aptamer.

Animals↗
PubMed1999

Evolution of interstellar ices.

Infrared observations, combined with realistic laboratory simulations, have revolutionized our understanding of interstellar ice and dust, the building blocks of comets. Ices in molecular clouds are dominated by the very simple molecules H2O, CH3OH, NH3, CO, CO2, and probably H2CO and H2. More complex species including nitriles, ketones, and esters are also present, but at lower concentrations. The evidence for these, as well as the abundant, carbon-rich, interstellar, polycyclic aromatic hydrocarbons (PAHs) is reviewed. Other possible contributors to the interstellar/pre-cometary ice composition include accretion of gas-phase molecules and in situ photochemical processing. By virtue of their low abundance, accretion of simple gas-phase species is shown to be the least important of the processes considered in determining ice composition. On the other hand, photochemical processing does play an important role in driving dust evolution and the composition of minor species. Ultraviolet photolysis of realistic laboratory analogs readily produces H2, H2CO, CO2, CO, CH4, HCO, and the moderately complex organic molecules: CH3CH2OH (ethanol), HC(=O)NH2 (formamide), CH3C(=O)NH2 (acetamide), R-CN (nitriles), and hexamethylenetetramine (HMT, C6H12N4), as well as more complex species including amides, ketones, and polyoxymethylenes (POMs). Inclusion of PAHs in the ices produces many species similar to those found in meteorites including aromatic alcohols, quinones and ethers. Photon assisted PAH-ice deuterium exchange also occurs. All of these species are readily formed and are therefore likely cometary constituents.

Carbon Monoxide↗
PubMed2000

Tissue factor in human coronary atherosclerotic plaques.

The rupture or fissuring of a coronary atherosclerotic plaque and subsequent thrombosis is considered the key event in the pathogenesis of unstable angina and myocardial infarction. Although plaque disruption frequently occurs during the evolution of atherosclerosis, only a minority of ruptured plaques develop thrombosis. The content and procoagulant activity of tissue factor in human coronary atherosclerotic plaques varies widely, and different studies confirm that it is higher in the plaques extracted from patients with unstable angina, myocardial infarction or histologic/angiographic evidence of coronary thrombosis than in those taken from patients with stable angina or uncomplicated coronary lesions. Variations in tissue factor content and activity may be responsible for the different thrombotic responses to human coronary atherosclerotic plaque rupture.

Coronary Artery Disease↗
PubMed2003

Lateral gene transfer: when will adolescence end?

The scope and impact of horizontal gene transfer (HGT) in Bacteria and Archaea has grown from a topic largely ignored by the microbiological community to a hot-button issue gaining staunch supporters (on particular points of view) at a seemingly ever-increasing rate. Opinions range from HGT being a phenomenon with minor impact on overall microbial evolution and diversification to HGT being so rampant as to obfuscate any opportunities for elucidating microbial evolution - especially organismal phylogeny - from sequence comparisons. This contentious issue has been fuelled by the influx of complete genome sequences, which has allowed for a more detailed examination of this question than previously afforded. We propose that the lack of common ground upon which to formulate consensus viewpoints probably stems from the absence of answers to four critical questions. If addressed, they could clarify concepts, reject tenuous speculation and solidify a robust foundation for the integration of HGT into a framework for long-term microbial evolution, regardless of the intellectual camp in which you reside. Here, we examine these issues, why their answers shape the outcome of this debate and the progress being made to address them.

Archaea↗
PubMed1996

Prospective follow-up study of 877 children born after intracytoplasmic sperm injection (ICSI), with ejaculated epididymal and testicular spermatozoa and after replacement of cryopreserved embryos obtained after ICSI.

A prospective follow-up study of 877 children born after ICSI was carried out. The aim of this study was to compile data on karyotypes, congenital malformations, growth parameters and developmental milestones so as to evaluate the safety of this new technique. The follow-up study included agreement to genetic counselling and prenatal diagnosis and was based on a physical examination at the Centre for Medical Genetics (Dutch-speaking Brussels Free University, Brussels, Belgium) at 2 months, 1 year and 2 years, when major and minor malformations and a psychomotor evolution were recorded. Between April 1991 and July 1995, 904 pregnancies obtained after intracytoplasmic sperm injection (ICSI) led to the birth of 877 children (465 singletons, 379 twins and 33 triplets). Prenatal diagnosis determined a total of 486 karyotypes, of which six were abnormal (1.2%) and six (1.2%) were familial structural aberrations, all transmitted from the father. This slight increase in de-novo chromosomal aberrations and the higher frequency of transmitted chromosomal aberrations are probably linked directly to the characteristics of the infertile men treated rather than to the ICSI procedure itself. In all, 23 (2.6%) major malformations were observed in the children born, defined as those causing functional impairment or requiring surgical correction. No particular malformation was disproportionately frequent. Compared with most registers of children born after assisted reproduction and with registers of malformation in the general population, the figure of 2.6% was within the expected range. These observations should be further completed by others and by collaborative efforts. In the meantime, patiens should be counselled about the available data before any treatment: the risk of transmitted chromosomal aberrations, the risk of de-novo, mainly sex chromosomal, aberrations and the risk of transmitting fertility problems to the offspring. Patients should also be reassured that there seems to be no higher incidence of congenital malformations in children born after ICSI.

Congenital Abnormalities↗
PubMed1988

Coxsackie virus heart disease: 15 years after.

From 1969 to 1973, 68 patients were admitted to the 4th Division of Medicine of the Brescia Civil Hospital with the diagnosis of viral myocarditis. The patients were divided into two groups according to the results of the Coxsackie virus complement fixing antibodies test: Group 1 (42 patients) with a fourfold or greater rising antibody titre; Group 2 (26 patients) with a negative serum test. Both groups were examined after a follow-up period of 15 years. Ten patients from Group 1 died. The diagnoses were chronic myocarditis (three cases); chronic cardiomyopathy-pulmonary embolism (one case); chronic cardiomyopathy-liver cirrhosis (one case); dilated cardiomyopathy-sudden death (two cases); congestive cardiomyopathy (three cases). No Group 2 patients died. The 15-year mortality rate of Group 1 was significantly higher than that of Group 2 (Fisher Test: p less than 0.005). In conclusion, the natural history of Coxsackie virus heart disease is characterized by two possibilities: a complete recovery from a clinical point of view, in some cases with only minor T wave abnormalities, or evolution into a chronic disease (dilated cardiomyopathy) having a high mortality rate within 10 years of the onset of the acute disease.

Cardiomyopathy, Dilated↗