SEARCH · PubMed Health

Results for “shared variables”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,621 records · Page 90Linked to original sources

PubMed2001

General relations among drug use, alcohol use, and major indexes of psychopathology.

Relations among measures of trait anxiety, depression, panic, somatization, alcohol use, drug use, and treatment for depression were investigated because, typically, studies (a) addressed relations among subsets of only 2 or 3 of the measures and (b) dealt almost exclusively with narrow samples of the population representing extremes on 1 or 2 of the measures. In this study, relations among all 7 measures were assessed with participants representing a wide range of scores on all the measures. The 369 participants (155 men, 214 women) were sampled from the general population. Three replications of the same study consistently yielded hypothesized positive intercorrelations among all 7 scales. Factor 1 (Anxiety-Depression) included Trait Anxiety, Depression, and Panic scales. Factor 2 (Substance Abuse) included Drug Use, Alcohol Use, Treatment for Depression, and Somatization scales. Factor 2 highlighted self-medication as a defining characteristic of somatizers and corroborated findings showing that substance abuse is often a precursor to treatment for depression-like symptoms that can be ameliorated with abstinence. Factors 1 and 2 were significantly intercorrelated (r = .41, df = 367, p < .05), showing a 17% shared variance in two common groupings of psychological dysfunction (anxiety-depression, substance abuse) in the general population. Thus, depending on socioeconomic and demographic variables, a third common form of dysfunction in the general population is represented by a combination of anxiety-depression plus substance abuse.

Adult↗

PubMed1953

The antigenic composition of influenza virus measured by antibody-absorption.

The application of methods herein described for the absorption of antibody from sera by influenza virus adsorbed to erythrocytes has greatly facilitated absorption studies with this virus and has resulted in a more comprehensive demonstration of strain differences and relationships. It is now evident that there are at least 18 different antigenic components which can be measured in Type A strains of influenza virus. Utilization of quantitative absorption technics allows the simultaneous detection of variable quantities of several different antigens so that the antigenic composite of the strain is more clearly defined than was previously possible. The wide sharing of antigenic components leads to the conclusion that no completely new antigens have formed of late nor have the antigenic components of strains isolated several years ago disappeared. Some mechanisms for antigenic variation among strains are suggested, and the significance of the variation in antigenic components is discussed in relation to specifications for an effective vaccine.

Antibodies↗

PubMed1997

Structure and conserved characteristics of Campylobacter jejuni lipopolysaccharides.

The lipid A component of Campylobacter jejuni lipopolysaccharides (LPSs) contains the same architectural principle as that found in other bacterial species; however, unlike the case with other bacterial species, the lipid A backbone of C. jejuni strains is composed of a phosphorylated beta(1'-6)-linked disaccharide containing 2,3-diamino-2,3-dideoxy-D-glucose and D-glucosamine as the major molecular species. Despite a backbone that differs structurally from that of classic enterobacterial lipid A, C. jejuni lipid A is antigenically similar to enterobacterial lipid A, and the respective LPSs have comparable endotoxic activities. Structural variability is greater in the core oligosaccharide than in lipid A of C. jejuni LPS. Nevertheless, the inner core oligosaccharides of C. jejuni strains share a common unique tetrasaccharide and also possess a trisaccharide that occurs in the inner core of other bacterial species. Ganglioside mimicry in the outer core is a common feature shared by a number of C. jejuni serotypes, but this mimicry is not conserved in all serotypes.

Campylobacter jejuni↗

PubMed2003

A random variance model for detection of differential gene expression in small microarray experiments.

MOTIVATION: Microarray techniques provide a valuable way of characterizing the molecular nature of disease. Unfortunately expense and limited specimen availability often lead to studies with small sample sizes. This makes accurate estimation of variability difficult, since variance estimates made on a gene by gene basis will have few degrees of freedom, and the assumption that all genes share equal variance is unlikely to be true. RESULTS: We propose a model by which the within gene variances are drawn from an inverse gamma distribution, whose parameters are estimated across all genes. This results in a test statistic that is a minor variation of those used in standard linear models. We demonstrate that the model assumptions are valid on experimental data, and that the model has more power than standard tests to pick up large changes in expression, while not increasing the rate of false positives. AVAILABILITY: This method is incorporated into BRB-ArrayTools version 3.0 (http://linus.nci.nih.gov/BRB-ArrayTools.html). SUPPLEMENTARY MATERIAL: ftp://linus.nci.nih.gov/pub/techreport/RVM_supplement.pdf

Algorithms↗

PubMed2001

Characterization of uracil-DNA glycosylase activity from Trypanosoma cruzi and its stimulation by AP endonuclease.

The intracellular pathogen Trypanosoma cruzi is the etiological agent of Chagas' disease. We have isolated a full-length cDNA encoding uracil-DNA glycosylase (UDGase), a key enzyme involved in DNA repair, from this organism. The deduced protein sequence is highly conserved at the C-terminus of the molecule and shares key residues involved in binding or catalysis with most of the UDGases described so far, while the N-terminal part is highly variable. The gene is single copy and is located on a chromosome of approximately 1.9 Mb. A His-tagged recombinant protein was overexpressed, purified and used to raise polyclonal antibodies. Western blot analysis revealed the existence of a single UDGase species in parasite extracts. Using a specific ethidium bromide fluorescence assay, recombinant T.cruzi UDGase was shown to specifically excise uracil from DNA. The addition of both Leishmania major AP endonuclease and exonuclease III, the major AP endonuclease from Escherichia coli, produces stimulation of UDGase activity. This activation is specific for AP endonuclease and suggests functional communication between the two enzymes.

Amino Acid Sequence↗

PubMed2006

Molecular determinants of ginkgolide binding in the glycine receptor pore.

Ginkgolides are potent blockers of the glycine receptor Cl- channel (GlyR) pore. We sought to identify their binding sites by comparing the effects of ginkgolides A, B and C and bilobalide on alpha1, alpha2, alpha1beta and alpha2beta GlyRs. Bilobalide sensitivity was drastically reduced by incorporation of the beta subunit. In contrast, the sensitivities to ginkgolides B and C were enhanced by beta subunit expression. However, ginkgolide A sensitivity was increased in the alpha2beta GlyR relative to the alpha2 GlyR but not in the alpha1beta GlyR relative to the alpha1 GlyR. We hypothesised that the subunit-specific differences were mediated by residue differences at the second transmembrane domain 2' and 6' pore-lining positions. The increased ginkgolide A sensitivity of the alpha2beta GlyR was transferred to the alpha1beta GlyR by the G2'A (alpha1 to alpha2 subunit) substitution. In addition, the alpha1 subunit T6'F mutation abolished inhibition by all ginkgolides. As the ginkgolides share closely related structures, their molecular interactions with pore-lining residues were amenable to mutant cycle analysis. This identified an interaction between the variable R2 position of the ginkgolides and the 2' residues of both alpha1 and beta subunits. These findings provide strong evidence for ginkgolides binding at the 2' pore-lining position.

Amino Acid Sequence↗

PubMed2006

Views of older adults on patient participation in medication-related decision making.

BACKGROUND: Medication decision making is complex, particularly for older patients with multiple conditions for whom benefits may be uncertain and health priorities may be variable. While patient input would seem important in the face of this uncertainty and variability, little is known about older patients' views of involvement in medication decision making. OBJECTIVE: To explore the views of older adults regarding participation in medication decision making. DESIGN: Qualitative study. PARTICIPANTS: Fifty-one persons at least 65 years old who consumed at least one medication were recruited from 3 senior centers and 4 physicians' offices. APPROACH: One-on-one interviews were conducted to uncover participants' perceptions of medication-related decision making through semistructured, open-ended questions. Themes were compared according to the constant comparative method of analysis. RESULTS: The predominant theme that emerged was the variability in perceptions concerning whether it was possible or desirable for patients to participate in prescribing decisions. For some participants, involvement was limited to sharing information. Physician and system factors that were felt to facilitate or impede patient participation included communication skills, the expanding number of medications available, multiple physicians prescribing for the same patient, and a focus on treating numbers. Perceived lack of knowledge, low self-efficacy, and fear were the patient factors mentioned. Both the presence and absence of trust in the prescribing physician were seen as alternatively impeding and enhancing patient participation. Only 1 participant explicitly mentioned patient preference, a cornerstone of shared decision making. CONCLUSIONS: While evolution to greater patient involvement in medication decision making may be possible, and desirable to some older patients, findings suggest that the transition will be challenging.

Age Factors↗

PubMed1996

CD4+ T-helper lymphocyte responses against Babesia bigemina rhoptry-associated protein I.

A multigene family of 58- to 60-kDa proteins, which are designated rhoptry-associated protein 1 (RAP-1) and which come from the parasites Babesia bigemina and Babesia bovis, is a target for vaccine development. The presence of multiple gene copies and conserved sequences and epitopes of RAP-1 implies that these proteins are functionally important for the survival of these parasites. Furthermore, it was previously shown that B. bigemina RAP-1 induced partial protection against challenge infection. However, the lack of correlation between protective immunity to B. bigemina infection and antibody titers against a merozoite surface-exposed, neutralization-sensitive epitope of B. bigemina RAP-1 indicated the potential importance of RAP-1-specific T helper (Th) cells in the observed protection. To begin to understand the mechanism of RAP-1-induced protective immunity, RAP-1-specific T-cell responses were characterized in cattle. Vigorous and sustained proliferative responses of peripheral blood mononuclear cells from native RAP-1-immunized cattle were observed. The anamnestic response in immunized cattle was specific for B. bigemina RAP-1 and predominantly comprised CD4+ T cells, which upon cloning expressed type 1 cytokine mRNA profiles and high levels of gamma interferon protein. The T cells responded to both native and recombinant forms of RAP-1, indicating the potential to use recombinant protein or epitopes derived therefrom as a vaccine that could evoke specific recall responses after exposure to natural infection. The differential responses of peripheral blood mononuclear cells and seven Th-cell clones derived from RAP-1-immunized cattle to different Central American strains of B. bigemina indicated the presence of at least one conserved and one variable Th-cell epitope. The lack of response to B. bovis RAP-1 indicated that a strictly conserved 14-amino-acid peptide shared by the two babesial species was not immunogenic for Th cells in these experiments. However, the Th-cell epitope conserved among strains of B. bigemina may be a useful component of a RAP-1 subunit vaccine.

Animals↗

PubMed1989

Plasmid structural instability associated with pC194 replication functions.

The hybrid plasmid pJS37 is composed of the streptococcal plasmid pLS1, which confers tetracycline resistance, and the staphylococcal plasmid pC194, which confers chloramphenicol resistance. When gram-positive bacteria containing pJS37 were grown in the presence of chloramphenicol, four different deleted derivatives accumulated. The deletions in the plasmid enhanced resistance to chloramphenicol by placing the cat gene of pC194 near promoters of pLS1. All four deletions shared a common endpoint that corresponded to the putative target site for DNA strand nicking by the pC194 replication protein, RepH. At the other, variable endpoint, the DNA sequence was similar to the putative RepH target sequence. Alteration of the RepH protein, by in vitro modification of the gene encoding it, eliminated this class of deletions. By extending a previously proposed model for the generation of a different but related class of deletions (B. Michel and S.D. Ehrlich, EMBO J. 5:3691-3696, 1986), a comprehensive model that could generate both classes of deletions is suggested. It proposes that a nicking-closing activity of the plasmid replication protein at its normal target site and, aberrantly, at sites with similar sequence can generate deletions either proximal or distal to the aberrant site during rolling-circle replication of the plasmid.

Bacterial Proteins↗

PubMed1990

Sequence variants of human T-cell lymphotropic virus type I from patients with tropical spastic paraparesis and adult T-cell leukemia do not distinguish neurological from leukemic isolates.

We have amplified and sequenced DNA in the envelope (env) and long terminal repeat (LTR) regions of human T-cell lymphotropic virus type I (HTLV-I) proviruses from the peripheral blood of 10 HTLV-I-seropositive patients with tropical spastic paraparesis (TSP) and two patients with adult T-cell leukemia. The aim was to examine variation in these regions and to test the hypothesis that the sequences of leukemogenic HTLV-I isolates differ from those causing the neurological disease TSP. In 5 of the 12 HTLV-I-seropositive patients, more than one HTLV-I sequence variant was identified in the same individual. No two individuals shared identical sequences in either env or LTR U3. Sequence variations were found at 73 positions in 1,416 bases amplified in env. Sequence variability was found throughout the LTR-U3 region, including the sequences of two transcriptional enhancers. Several nucleotide changes common to both Caribbean and Japanese HTLV-I isolates allowed us to identify a consensus sequence that differs from the HTLV-I prototype sequence (M. Seiki, S. Hattori, Y. Hirayama, and M. Yoshida, Proc. Natl. Acad. Sci. USA 80:3618-3622, 1983). No sequence in the env or LTR U3 region was found to be characteristic of isolates from TSP patients. Although each isolate was distinct at the nucleotide level, the predicted protein sequence of HTLV-I env is less variable than that of human immunodeficiency virus env, suggesting that these lymphotropic retroviruses use different strategies to evade host immune responses.

Adult↗

PubMed2004

Rapid diagnosis of Ebola hemorrhagic fever by reverse transcription-PCR in an outbreak setting and assessment of patient viral load as a predictor of outcome.

The largest outbreak on record of Ebola hemorrhagic fever (EHF) occurred in Uganda from August 2000 to January 2001. The outbreak was centered in the Gulu district of northern Uganda, with secondary transmission to other districts. After the initial diagnosis of Sudan ebolavirus by the National Institute for Virology in Johannesburg, South Africa, a temporary diagnostic laboratory was established within the Gulu district at St. Mary's Lacor Hospital. The laboratory used antigen capture and reverse transcription-PCR (RT-PCR) to diagnose Sudan ebolavirus infection in suspect patients. The RT-PCR and antigen-capture diagnostic assays proved very effective for detecting ebolavirus in patient serum, plasma, and whole blood. In samples collected very early in the course of infection, the RT-PCR assay could detect ebolavirus 24 to 48 h prior to detection by antigen capture. More than 1,000 blood samples were collected, with multiple samples obtained from many patients throughout the course of infection. Real-time quantitative RT-PCR was used to determine the viral load in multiple samples from patients with fatal and nonfatal cases, and these data were correlated with the disease outcome. RNA copy levels in patients who died averaged 2 log(10) higher than those in patients who survived. Using clinical material from multiple EHF patients, we sequenced the variable region of the glycoprotein. This Sudan ebolavirus strain was not derived from either the earlier Boniface (1976) or Maleo (1979) strain, but it shares a common ancestor with both. Furthermore, both sequence and epidemiologic data are consistent with the outbreak having originated from a single introduction into the human population.

Antigens, Viral↗

PubMed2005

Genetic and environmental influences of surfactant protein D serum levels.

The collectin surfactant protein D (SP-D) is an important component of the pulmonary innate immune system, but SP-D is also present on extrapulmonary epithelial surfaces and in serum, where it has been used as a biomarker for pulmonary disease states. In this study, we investigate the mechanisms defining the constitutional serum level of SP-D and determine the magnitude of the genetic contribution to serum SP-D in the adult population. Recent studies have demonstrated that serum SP-D concentrations in children are genetically determined and that a single nucleotide polymorphism (SNP) located in the NH(2)-terminal region (Met11Thr) of the mature protein is significantly associated with the serum SP-D levels. A classic twin study was performed on a twin population including 1,476 self-reported healthy adults. The serum SP-D levels increased with male sex, age, and smoking status. The intraclass correlation was significantly higher for monozygotic (MZ) twin pairs than for dizygotic (DZ) twin pairs. Serum SP-D variance was influenced by nonshared environmental effects and additive genetic effects. Multivariate analysis of MZ and DZ covariance matrixes showed significant genetic correlation among serum SP-D and metabolic variables. The Met11Thr variant explained a significant part of the heritability indicating that serum SP-D variance could be decomposed into non-shared environmental effects (e(2) = 0.19), additive genetic effects (h(2) = 0.42), and the effect of the Met11Thr variations (q(2) = 0.39).

Adolescent↗

PubMed1970

Pathways of fatty acid metabolism in human platelets.

The metabolic fate of (14)C-labeled fatty acids which have been incubated with human platelets, has been traced. The following has been shown. (a) Intact platelets have a considerable capacity to oxidize fatty acids. (b) When tracer amounts of four of the most common fatty acids in normal plasma were incubated with platelets, each showed a distinctive pattern of uptake among neutral lipids and phospholipids. With regard to the latter, it was shown that these distribution patterns were, in most cases, similar to those of the fatty acids found in natural platelet phospholipids. (c) By increasing the time of incubation or the amount of added oleic acid, the distribution of oleic acid uptake between lecithin and other phosphoglycerides was altered so that a larger share was incorporated into the latter. (d) The effects of added lysolecithin or lysoethanolamine phosphoglycerides on oleic acid incorporation into platelet phosphoglycerides are quite variable. At low concentrations, added lysolecithin functions chiefly as a reaction partner for oleic acid. Added adenosine triphosphate and CoASH augment the incorporation of oleic acid into lecithin over a wide range of added lysolecithin (12.5-500 mumoles/liter). At higher concentrations of added lysolecithin, in the absence of ATP and CoASH, oleic acid incorporation into lecithin is considerably reduced. Also, added lysolecithin and lysoethanolamine phosphoglycerides, in the absence of ATP and CoASH, are able, at certain concentrations, to stimulate oleic acid incorporation into all except the serine phosphoglycerides. (e) Platelets appear to have a de novo pathway for renewal of lecithin.

Adenosine Triphosphate↗

PubMed2004

Patterns of childhood sexual abuse characteristics and their relationships to other childhood abuse and adult health.

The purpose of this study was twofold: (a) to cluster women who experienced childhood sexual abuse (CSA) according to their shared patterns of CSA characteristics and (b) to examine differences across clusters on measures of other childhood abuse and adult health. Seven CSA characteristic variables were used for cluster analysis. The seven-cluster solution that emerged ranged from a noncontact extrafamilial CSA cluster that occurred without force only once to the most severe clusters in which penetration by an intrafamilial or extrafamilial abuser occurred multiple times with force. Significant differences among clusters were found for childhood emotional abuse and physical abuse, adult physical and psychosocial symptomatology, and depression. There were no significant differences for health care utilization. The results promote further understanding of which victims of CSA are more likely to have experienced other forms of childhood abuse and which victims are more at risk for poor health in adulthood.

Adolescent↗

PubMed2005

Genetic determinants and personality correlates of sociopolitical attitudes in a Polish sample.

The aim of the study was to assess the heritability as well as the personality correlates of sociopolitical attitudes in a Polish sample. Attitudes were examined on two separate dimensions: (1) moral conservatism and liberalism; and (2) free market economy and state interventionism. The studied sample comprised three groups of participants: (1) 242 twin pairs aged 18 to 25 years (119 monozygotic [MZ] and 123 dizygotic [DZ] same-sex twins reared together); (2) 358 females and males ('nontwins') of various professions aged 35 to 64 years; and (3) 197 male and female technical university students aged 19 to 25 years ('nontwins'). We detected substantial genetic factor input exclusively in the variability of results on the conservatism-liberalism scale (.28). Results on both scales were explained to a large extent by the impact of shared environment, and to a lesser extent by the nonshared environment. Only in the student group was a significant negative correlation found between attitudes toward economy and neuroticism, extraversion, agreeableness and conscientiousness. Openness to experience correlated negatively with attitudes towards issues of morality in the adult female and male group (the remaining correlations were statistically insignificant).

Adolescent↗

PubMed2005

Genetic and molecular characterization of the I locus of Phaseolus vulgaris.

The I locus of the common bean, Phaseolus vulgaris, controls the development of four different phenotypes in response to inoculation with Bean common mosaic virus, Bean common mosaic necrosis virus, several other related potyviruses, and one comovirus. We have generated a high-resolution linkage map around this locus and have aligned it with a physical map constructed with BAC clones. These clones were obtained from a library of the cultivar "Sprite," which carries the dominant allele at the I locus. We have identified a large cluster of TIR-NBS-LRR sequences associated within this locus, which extends over a distance >425 kb. Bean cultivars from the Andean or Mesoamerican gene pool that contain the dominant allele share the same haplotypes as revealed by gel blot hybridizations with a TIR probe. In contrast, beans with a recessive allele display simpler and variable haplotypes. A survey of wild accessions from Argentina to Mexico showed that this multigene family has expanded significantly during evolution and domestication. RNA gel blot analysis indicated that the TIR family of genes plays a role in the response to inoculations with BCMV or BCMNV.

Amino Acid Sequence↗

PubMed2000

RAPD marker diversity within and divergence among species of Dendroseris (Asteraceae: Lactuceae).

Random Amplified Polymorphic DNA (RAPD) markers were used to measure genetic diversity within and divergence among species of Dendroseris (Asteraceae: Lactuceae), a genus endemic to the Juan Fernandez Islands, Chile. Results were compared to previous studies employing allozymes. For five of the species, RAPD banding patterns distinguished all individuals examined, and different mutilocus genotypes were found even in species exhibiting no allozyme diversity. RAPD band diversities ranged from 0.003 to 0.022 within species; >90% of total diversity was among species and <10% within them. Relative levels of allozyme and RAPD diversity were similar for some species, particularly those with highest and lowest diversities, but overall there was no significant correlation. Relationships inferred from a neighbor-joining tree generated from RAPD bands were similar to results obtained from morphology, chloroplast DNA (cpDNA) restriction site mutations, and sequences from the internal transcribed spacer regions of nuclear ribosomal DNA (ITS), but somewhat better resolution was achieved. Relationships shown by allozymes differed from trees based on other data; this ostensibly is a result of the sharing of ancestral alleles and the absence of alleles generated subsequent to speciation. Dendroseris represents an example where RAPD markers, because of their greater variability, provide a useful alternative to allozymes for assessing diversity in rare species endemic to oceanic islands and for resolving relationships among the species.

Journal Article↗

PubMedDate not supplied

Myofibrillar (desmin-related) myopathy: clinico-pathological spectrum in 3 cases and review of the literature.

Myofibrillar or desmin-related myopathies encompass neuromuscular disorders with abnormal deposits of desmin and myofibrillar alterations. We report 3 unrelated patients presenting with proximal and distal myopathy, and, as a unique congenital syndrome, diffusely distributed myopathy, osteoporosis and myopia. Muscle biopsies shared cytoplasmic inclusions, rimmed vacuoles, and ragged-red-like fibers. Sarcoplasmic inclusions, either plaque-like or amorphous, strongly immunoreacted on dystrophin and variably for desmin, alphaB crystallin and ubiquitin. Cyclin-dependent kinases CDK1, CDK2 and CDK5 were overexpressed in affected fibers. Ultrastructurally, focal myofibrillar disruption was accompanied by tubulo-filamentous inclusions in one case and abundant glycogen and enlarged mitochondria displaying respiratory chain dysfunction at biochemistry in another case. Molecular analysis of the alphaB crystallin gene coding sequence and exons 4, 5 and 6 of the desmin gene did not reveal any mutation. The morphologic denominator of hyaline structures and areas of myofibrillar destruction occurs in heterogeneous conditions and may overlap with features of inclusion body myopathy and mitochondrial myopathy.

Adult↗