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Biomedical subjects

Robert Cole

Publications and source records attributed to Robert Cole.

8 recordsLinked to original sources

Comparison of myocardial velocities obtained with magnetic resonance phase velocity mapping and tissue Doppler imaging in normal subjects and patients with left ventricular dyssynchrony.

PURPOSE: To compare longitudinal myocardial velocity and time to peak longitudinal velocity obtained with magnetic resonance phase velocity mapping (MR-PVM) and tissue Doppler imaging (TDI), and to assess the reproducibility of each method. MATERIALS AND METHODS: Longitudinal myocardial velocity was measured by TDI and MR-PVM in 10 normal volunteers and 10 patients with dyssynchrony. The reproducibility of MR-PVM and TDI was assessed on repeated measurements in the 10 normal volunteers. RESULTS: MR and TDI measurements of longitudinal myocardial velocity correlated well (r = 0.86) in both normal subjects and patients with dyssynchrony. However, myocardial velocities measured with MR consistently exceeded velocities measured with TDI. MR and TDI agreed strongly in measuring the time to peak velocity (r = 0.97). The reproducibility of TDI and MR-PVM appeared similar in measuring peak velocities (13.1% vs. 11.0%, respectively; P = NS) and time to peak velocity (9.1% vs. 5.7%, respectively; P = NS). CONCLUSION: Excellent correlation and reproducibility were observed between MR-PVM and TDI in measuring longitudinal myocardial velocity and time to peak velocity in both normal subjects and patients with dyssynchrony.

Adult↗

Composite genome map and recombination parameters derived from three archetypal lineages of Toxoplasma gondii.

Toxoplasma gondii is a highly successful protozoan parasite in the phylum Apicomplexa, which contains numerous animal and human pathogens. T.gondii is amenable to cellular, biochemical, molecular and genetic studies, making it a model for the biology of this important group of parasites. To facilitate forward genetic analysis, we have developed a high-resolution genetic linkage map for T.gondii. The genetic map was used to assemble the scaffolds from a 10X shotgun whole genome sequence, thus defining 14 chromosomes with markers spaced at approximately 300 kb intervals across the genome. Fourteen chromosomes were identified comprising a total genetic size of approximately 592 cM and an average map unit of approximately 104 kb/cM. Analysis of the genetic parameters in T.gondii revealed a high frequency of closely adjacent, apparent double crossover events that may represent gene conversions. In addition, we detected large regions of genetic homogeneity among the archetypal clonal lineages, reflecting the relatively few genetic outbreeding events that have occurred since their recent origin. Despite these unusual features, linkage analysis proved to be effective in mapping the loci determining several drug resistances. The resulting genome map provides a framework for analysis of complex traits such as virulence and transmission, and for comparative population genetic studies.

Animals↗

Reducing the impact of uncontrollable stressful life events through a program of nurse home visitation for new parents.

The current study examined whether the Nurse Family Partnership (NFP), an intervention in which mothers received home visitation by registered nurses pre- and postnatally, reduced mothers' vulnerability to the effects of stressful life events several years after the program was completed. Data from a randomized trial of the NFP were examined for mothers (N = 324) who were generally low-income, young, and unmarried at the time of the birth of their first child. Structured interviews were done with mothers about 15 years after the program began. Results showed that experiencing uncontrollable stressful life events, such as the death of a loved one, led to fewer negative outcomes (fewer mental health problems, less binge drinking, and better parenting practices) among nurse-visited mothers than among mothers receiving no visitation. Furthermore, the program's effect on reducing vulnerability to the negative impact of life events was particularly evident among parents who were younger or had a lower sense of personal control at intake. These findings suggest that, in addition to preventing the occurrence of negative outcomes that were direct targets of the intervention, the NFP more generally enhanced mothers' ability to cope with future stressful life events.

Adult↗

Effects of nurse home-visiting on maternal life course and child development: age 6 follow-up results of a randomized trial.

OBJECTIVE: To test, with an urban, primarily black sample, the effects of prenatal and infancy home visits by nurses on mothers' fertility and economic self-sufficiency and the academic and behavioral adjustment of their children as the children finished kindergarten, near their sixth birthday. METHODS: We conducted a randomized, controlled trial of a program of prenatal and infancy home-visiting in a public system of obstetric and pediatric care in Memphis, Tennessee. A total of 743 primarily black women at <29 weeks of gestation, with no previous live births and with > or =2 sociodemographic risk characteristics (unmarried, <12 years of education, or unemployed), were randomly assigned to receive nurse home visits or comparison services. Outcomes consisted of women's number and timing of subsequent pregnancies, months of employment, use of welfare, food stamps, and Medicaid, educational achievement, behavioral problems attributable to the use of substances, rates of marriage and cohabitation, and duration of relationships with partners and their children's behavior problems, responses to story stems, intellectual functioning, receptive language, and academic achievement. RESULTS: In contrast to counterparts assigned to the comparison group, women visited by nurses had fewer subsequent pregnancies and births (1.16 vs 1.38 pregnancies and 1.08 vs 1.28 births, respectively), longer intervals between births of the first and second children (34.28 vs 30.23 months), longer relationships with current partners (54.36 vs 45.00 months), and, since the previous follow-up evaluation at 4.5 years, fewer months of using welfare (7.21 vs 8.96 months) and food stamps (9.67 vs 11.50 months). Nurse-visited children were more likely to have been enrolled in formal out-of-home care between 2 and 4.5 years of age (82.0% vs 74.9%). Children visited by nurses demonstrated higher intellectual functioning and receptive vocabulary scores (scores of 92.34 vs 90.24 and 84.32 vs 82.13, respectively) and fewer behavior problems in the borderline or clinical range (1.8% vs 5.4%). Nurse-visited children born to mothers with low levels of psychologic resources had higher arithmetic achievement test scores (score of 88.61 vs 85.42) and expressed less aggression (score of 98.58 vs 101.10) and incoherence (score of 20.90 vs 29.84) in response to story stems. There were no statistically significant program effects on women's education, duration of employment, rates of marriage, being in a partnered relationship, living with the father of the child, or domestic violence, current partner's educational level, or behavioral problems attributable to the use of alcohol or drugs. CONCLUSION: This program of prenatal and infancy home-visiting by nurses continued to improve the lives of women and children at child age 6 years, 4 years after the program ended.

Adolescent↗

The coactivator of transcription CREB-binding protein interacts preferentially with the glycosylated form of Stat5.

The signal transducer and activator of transcription (Stat) gene family comprises seven members with similarities in their domain structure and a common mode of activation. Members of this gene family mediate interferon induction of gene transcription and the response to a large number of growth factors and hormones. Extracellular ligand binding to transmembrane receptors causes the intracellular activation of associated tyrosine kinases, phosphorylation of Stat molecules, dimerization, and translocation to the nucleus. Prolactin-induced phosphorylation of Stat5 is a key event in the development and differentiation of mammary epithelial cells. In addition to the crucial phosphorylation at tyrosine 694, we have identified an O-linked N-acetylglucosamine (O-GlcNAc) as another secondary modification essential for the transcriptional induction by Stat5. This modification was only found on nuclear Stat5 after cytokine activation. Similar observations were made with Stat1, Stat3, and Stat6. Glycosylation of Stat5, however, does not seem to be a prerequisite for nuclear translocation. Mass spectrometric analysis revealed a glycosylated peptide in the N-terminal region of Stat5. Replacement of threonine 92 by an alanine residue (Stat5a-T92A) strongly reduced the prolactin induction of Stat5a glycosylation and abolished transactivation of a target gene promoter. Only the glycosylated form of Stat5 was able to bind the coactivator of transcription CBP, an essential interaction for Stat5-mediated gene transcription.

Acetylglucosamine↗

Testing the relationship between self-agency and enactment of health behaviors.

A theoretical review provides a rationale for examining self-agency as a developmental foundation underlying processes of self-regulated change and a potential moderator of intervention effectiveness among participants in a nurse home-visitation program. Self-agency is defined as the conceptual understanding of self as an agent capable of shaping motives, behavior, and future possibilities (Damon & Hart, 1991). Availability of a sample of 186 mothers who received nurse home visitation provided an opportunity to test the relationship between participant self-agency and enactment of targeted health behaviors. Self-agency items from the Pearlin Mastery Scale (1978) were used to differentiate mothers who endorsed self-agency from those who did not. Consistent with the theoretical premise, mothers who endorsed self-agency at an established threshold were significantly more likely to enact health behaviors promoted during nurse visitation. Results provide support for the relationship between the development of self-agency and enactment of health behaviors targeted by a nurse home-visitation program.

Adolescent↗

Academic growth curve trajectories from 1st grade to 12th grade: effects of multiple social risk factors and preschool child factors.

This study examined the main and interactive effects of multiple social risk factors and the preschool child factors of IQ and mental health on students' academic trajectories from 1st grade to 12th grade. A multiple risk score summarizing 10 environmental risk factors was calculated at 4 years of age for 145 families. Hierarchical linear modeling showed that high-risk students had lower grades and more absences from 1st grade to 12th grade than did low-risk students. Significant interactions between risk and child factors for students' grade point average (GPA) revealed that child factors had significant effects only for low-risk students. Higher IQ and better mental health improved the GPA trajectories of low-risk children but did not influence the GPA trajectories of high-risk children.

Adaptation, Psychological↗

Genome diversification in Staphylococcus aureus: Molecular evolution of a highly variable chromosomal region encoding the Staphylococcal exotoxin-like family of proteins.

Recent genomic studies have revealed extensive variation in natural populations of many pathogenic bacteria. However, the evolutionary processes which contribute to much of this variation remain unclear. A previous whole-genome DNA microarray study identified variation at a large chromosomal region (RD13) of Staphylococcus aureus which encodes a family of proteins with homology to staphylococcal and streptococcal superantigens, designated staphylococcal exotoxin-like (SET) proteins. In the present study, RD13 was found in all 63 S. aureus isolates of divergent clonal, geographic, and disease origins but contained a high level of variation in gene content in different strains. A central variable region which contained from 6 to 10 different set genes, depending on the strain, was identified, and DNA sequence analysis suggests that horizontal gene transfer and recombination have contributed to the diversification of RD13. Phylogenetic analysis based on the RD13 DNA sequence of 18 strains suggested that loss of various set genes has occurred independently several times, in separate lineages of pathogenic S. aureus, providing a model to explain the molecular variation of RD13 in extant strains. In spite of multiple episodes of set deletion, analysis of the ratio of silent substitutions in set genes to amino acid replacements in their products suggests that purifying selection (selective constraint) is acting to maintain SET function. Further, concurrent transcription in vitro of six of the seven set genes in strain COL was detected, indicating that the expression of set genes has been maintained in contemporary strains, and Western immunoblot analysis indicated that multiple SET proteins are expressed during the course of human infections. Overall, we have shown that the chromosomal region RD13 has diversified extensively through episodes of gene deletion and recombination. The coexpression of many set genes and the production of multiple SET proteins during human infection suggests an important role in host-pathogen interactions.

Animals↗