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J Taylor

Publications and source records attributed to J Taylor.

At least 109 records · Page 6Linked to original sources

Changing the landscape: a new strategy for estimating large phylogenies.

In this paper we describe a new heuristic strategy designed to find optimal (parsimonious) trees for data sets with large numbers of taxa and characters. This new strategy uses an iterative searching process of branch swapping with equally weighted characters, followed by swapping with reweighted characters. This process increases the efficiency of the search because, after each round of swapping with reweighted characters, the subsequent swapping with equal weights will start from a different group (island) of trees that are only slightly, if at all, less optimal. In contrast, conventional heuristic searching with constant equal weighting can become trapped on islands of suboptimal trees. We test the new strategy against a conventional strategy and a modified conventional strategy and show that, within a given time, the new strategy finds trees that are markedly more parsimonious. We also compare our new strategy with a recent, independently developed strategy known as the Parsimony Ratchet.

Animals↗

Negative regulation of the serine/threonine kinase B-Raf by Akt.

B-Raf contains multiple Akt consensus sites located within its amino-terminal regulatory domain. One site, Ser(364), is conserved with c-Raf but two additional sites, Ser(428) and Thr(439), are unique to B-Raf. We have investigated the role of both the conserved and unique phosphorylation sites in the regulation of B-Raf activity in vitro and in vivo. We show that phosphorylation of B-Raf by Akt occurs at multiple residues within its amino-terminal regulatory domain, at both the conserved and unique phosphorylation sites. The alteration of the serine residues within the Akt consensus sites to alanines results in a progressive increase in enzymatic activity in vitro and in vivo. Furthermore, expression of Akt inhibits epidermal growth factor-induced B-Raf activity and inhibition of Akt with LY294002 up-regulates B-Raf activity, suggesting that Akt negatively regulates B-Raf in vivo. Our results demonstrate that B-Raf activity can be negatively regulated by Akt through phosphorylation in the amino-terminal regulatory domain of B-Raf. This cross-talk between the B-Raf and Akt serine/threonine kinases is likely to play an important role in modulating the signaling specificity of the Ras/Raf pathway and in promoting biological outcome.

Amino Acid Sequence↗

Demographic, belief, and situational factors influencing the decision to utilize emergency medical services among chest pain patients. Rapid Early Action for Coronary Treatment (REACT) study.

BACKGROUND: Empirical evidence suggests that people value emergency medical services (EMS) but that they may not use the service when experiencing chest pain. This study evaluates this phenomenon and the factors associated with the failure to use EMS during a potential cardiac event. METHODS AND RESULTS: Baseline data were gathered from a randomized, controlled community trial (REACT) that was conducted in 20 US communities. A random-digit-dial survey documented bystander intentions to use EMS for cardiac symptoms in each community. An emergency department surveillance system documented the mode of transport among chest pain patients in each community and collected ancillary data, including situational factors surrounding the chest pain event. Logistic regression identified factors associated with failure to use EMS. A total of 962 community members responded to the phone survey, and data were collected on 875 chest pain emergency department arrivals. The mean proportion of community members intending to use EMS during a witnessed cardiac event was 89%; the mean proportion of patients observed using the service was 23%, with significant geographic differences (range, 10% to 48% use). After controlling for covariates, non-EMS users were more likely to try antacids/aspirin and call a doctor and were less likely to subscribe to (or participate in) an EMS prepayment plan. CONCLUSIONS: The results of this study indicate that indecision, self-treatment, physician contact, and financial concerns may undermine a chest pain patient's intention to use EMS.

Adult↗

Carbon nanotube based magnetic tunnel junctions

Spin-coherent quantum transport in carbon nanotube magnetic tunnel junctions is investigated theoretically. A spin-valve effect is found for metallic, armchair tubes, with a magnetoconductance ratio ranging up to 20%. Because of the finite length of the nanotube junctions, transport is dominated by resonant transmission. The magnetic tunnel junctions are found to have distinctly different transport behavior depending on whether or not the length of the tubes is commensurate with a 3N+1 rule, with N the number of basic carbon repeat units along the nanotube length.

Journal Article↗

Tenascin-R inhibits regrowth of optic fibers in vitro and persists in the optic nerve of mice after injury.

Tenascin-R, an extracellular matrix constituent expressed by oligodendrocytes and some neuronal cell types, may contribute to the inhibition of axonal regeneration in the adult central nervous system. Here we show that outgrowth of embryonic and adult retinal ganglion cell axons from mouse retinal explants is significantly reduced on homogeneous substrates of tenascin-R or a bacterially expressed tenascin-R fragment comprising the epidermal growth factor-like repeats (EGF-L). When both molecules are presented as a sharp substrate border, regrowing adult axons do not cross into the tenascin-R or EGF-L containing territory. All in vitro experiments were done in the presence of laminin, which strongly promotes growth of embryonic and adult retinal axons, suggesting that tenascin-R and EGF-L actively inhibit axonal growth. Contrary to the disappearance of tenascin-R from the regenerating optic nerve of salamanders (Becker et al., J Neurosci 19:813-827, 1999), the molecule remains present in the lesioned optic nerve of adult mice at levels similar to those in unlesioned control nerves for at least 63 days post-lesion (the latest time point investigated), as shown by immunoblot analysis and immunohistochemistry. In situ hybridization analysis revealed an increase in the number of cells expressing tenascin-R mRNA in the lesioned nerve. We conclude that, regardless of the developmental stage, growth of retinal ganglion cell axons is inhibited by tenascin-R and we suggest that the continued expression of the protein after an optic nerve crush may contribute to the failure of adult retinal ganglion cells to regenerate their axons in vivo.

Animals↗

Improving rheumatologists' screening for alcohol use and sexual activity.

OBJECTIVES: To design, implement, and assess the impact of an office-based intervention designed to improve rheumatologists' identification of risk behaviors, especially alcohol use and sexual activity, among adolescents and young adults with chronic rheumatologic conditions. DESIGNS: Prospective intervention study. SETTING: Midwestern academic pediatric rheumatology practice. PARTICIPANTS: Ten attending rheumatologists and fellows and 178 patients (mean age, 18.1 years; 67% female; 88% white; 69% with juvenile rheumatoid arthritis) seen in the practice during the baseline and intervention years. MAIN OUTCOME MEASURES: Change in the rate of screening for alcohol use and sexual activity from the baseline to the intervention year, and physician perceptions of the intervention. RESULTS: Screening for alcohol use increased from 4.2% (9/208) at baseline to 31.6% (56/177) after the intervention (P<.001). Of those patients undergoing screening at follow-up, 20 (36%) of 56 patients reported any alcohol use and 11 (20%) reported current alcohol use. Of those reporting current use, 7 (64%) were counseled or referred. Methotrexate use increased the likelihood of alcohol screening (43% [33/76] vs 26% 123/871; P = .02). Screening for sexual activity increased from 12.4% (27/ 218) to 36.2% (64/177) (P<.001) from baseline to follow-up. Of 52 females undergoing screening at follow-up, 31 (60%) were sexually active. Eleven (41%) of 27 sexually active females were not using contraception other than condoms (4 were not asked about contraception); 7 (82%) of these were referred for contraceptive counseling. Seven rheumatologists completed in-depth semistructured interviews after the intervention. All reported time as a main barrier to screening. Other barriers included logistical problems, discomfort with the subject area, ambivalence about whether risk behavior screening is the province of pediatric rheumatologists, and perceived lack of applicability to their patients. CONCLUSIONS: Despite knowledge and concern about the interaction of immunosuppressive therapy and risk behaviors, few rheumatologists adequately screen the behavior of their adolescent and young adult patients. Time constraints, organizational issues, and physician beliefs remain barriers to widespread screening.

Adolescent↗

Syntheses and biological activities of sandostatin analogs containing stereochemical changes in positions 6 or 8.

In a continuation of our research efforts on the design and synthesis of novel peptidomimetic structures, we have synthesized a series of sandostatin amide analogs in which stereoisomers of threonine and beta-hydroxyvaline(beta-Hyv) are employed. The analogs D-Phe1-c[Cys2-Phe3-D-Trp4-Lys5-Xaa6-Cys 7]-Xbb8-NH2 (Xaa = allo-Thr, D-allo-Thr, D-beta-Hyv, beta-Hyv, D-Thr, and Xbb = Thr or Xaa = Thr and Xbb = allo-Thr, D-allo-Thr, beta-Hyv, D-Thr) explore the effects on biological activity of stereochemical modifications and beta-methylation at positions 6 or 8. By these modifications, we examine the role of the two residues in binding to somatostatin receptors. We describe the synthesis and biological activity of these analogs. In combination with the results of the conformational analysis, this study provides new insights into the structural requirements for the binding affinity of somatostatin amide analogs to somatostatin receptors [Mattern et al., Conformational analyses of sandostatin analogs containing stereochemical changes in positions 6 or 8].

Animals↗

Social, emotional, and behavioral functioning of children with juvenile rheumatoid arthritis.

OBJECTIVE: To investigate the hypothesis that children with juvenile rheumatoid arthritis (JRA) would have more social and emotional problems than case-control classmates. METHODS: Using a case-control design, children with JRA (n = 74), ages 8-14, were compared with case-control classmates (n = 74). Peer relationships, emotional well-being, and behavior, based on peer-, teacher-, parent-, and self-report scores on common measures, were compared using analysis of variance. RESULTS: Relative to case-control classmates, children with JRA were similar on all measures of social functioning and behavior. Mothers reported more internalizing symptoms in the child with JRA, but child self reports and father reports showed no differences. Scores on all standardized measures were in the normal range for both the JRA and the case-control groups. CONCLUSION: Children with JRA were remarkably similar to case-control children on measures of social functioning, emotional well-being, and behavior. These findings are not supportive of disability/stress models of chronic illness in childhood and suggest considerable psychological hardiness among children with JRA.

Adolescent↗

Rapid analysis of high-dimensional bioprocesses using multivariate spectroscopies and advanced chemometrics.

There are an increasing number of instrumental methods for obtaining data from biochemical processes, many of which now provide information on many (indeed many hundreds) of variables simultaneously. The wealth of data that these methods provide, however, is useless without the means to extract the required information. As instruments advance, and the quantity of data produced increases, the fields of bioinformatics and chemometrics have consequently grown greatly in importance. The chemometric methods nowadays available are both powerful and dangerous, and there are many issues to be considered when using statistical analyses on data for which there are numerous measurements (which often exceed the number of samples). It is not difficult to carry out statistical analysis on multivariate data in such a way that the results appear much more impressive than they really are. The authors present some of the methods that we have developed and exploited in Aberystwyth for gathering highly multivariate data from bioprocesses, and some techniques of sound multivariate statistical analyses (and of related methods based on neural and evolutionary computing) which can ensure that the results will stand up to the most rigorous scrutiny.

Algorithms↗

The domineering non-autonomy of frizzled and van Gogh clones in the Drosophila wing is a consequence of a disruption in local signaling.

The frizzled (fz) gene is required for the development of distally pointing hairs on the Drosophila wing. It has been suggested that fz is needed for the propagation of a signal along the proximal distal axis of the wing. The directional domineering non-autonomy of fz clones could be a consequence of a failure in the propagation of this signal. We have tested this hypothesis in two ways. In one set of experiments we used the domineering non-autonomy of fz and Vang Gogh (Vang) clones to assess the direction of planar polarity signaling in the wing. prickle (pk) mutations alter wing hair polarity in a cell autonomous way, so pk cannot be altering a global polarity signal. However, we found that pk mutations altered the direction of the domineering non-autonomy of fz and Vang clones, arguing that this domineering non-autonomy is not due to an alteration in a global signal. In a second series of experiments we ablated cells in the pupal wing. We found that a lack of cells that could be propagating a long-range signal did not alter hair polarity. We suggest that fz and Vang clones result in altered levels of a locally acting signal and the domineering non-autonomy results from wild-type cells responding to this abnormal signal.

Alleles↗

Evidence for a genetic etiology of early-onset delinquency.

Age at onset of antisocial behavior discriminates persistent and transitory offenders. The authors proposed that early-onset delinquency has an underlying genetic influence that manifests in problems related to inhibition, whereas late-onset delinquency is more environmentally mediated. To test these notions, they selected 36 early starters, 86 late starters, and 25 nondelinquent controls from a large sample of 11-year-old twins and compared them on several measures related to inhibition and a peer group measure. As expected, early starters had more psychological, behavioral, and emotional problems related to inhibition than late starters and controls. A longitudinal analysis indicated an increase an antisocial behavior among peers of late starters shortly before their delinquency onset. Family history data and a twin analysis provided evidence of greater genetic influence on early-onset than late-onset delinquency.

Adolescent↗

Sebum excretion rates in mothers and neonates.

As neonates have a high sebum production compared with 6-month-old babies, we wished to investigate the relationship of sebum production in mother and neonate. The sebum excretion rate (SER) was therefore measured in 10 mothers prenatally, and in each mother and baby as soon after birth as possible, and again 5-12 weeks postnatally. There was a significant correlation between the maternal and neonatal SER perinatally. The perinatal SER in the babies was markedly higher than the postnatal sample. These observations suggest an important role for the maternal hormonal environment on the infant sebaceous glands. There is animal evidence which suggests that the endocrine environment of the neonate influences the sebaceous gland development in puberty, but it is not known whether babies with a high SER are more prone to seborrhoea and acne in later life.

Acne Vulgaris↗

Candidate gene analysis of thyroid hormone receptors in metamorphosing vs. nonmetamorphosing salamanders.

We used two different experimental approaches to test the hypothesis that thyroid hormone receptor (TR) variation is associated with alternate life cycles modes in ambystomatid salamanders. In the first experiment, the inheritance of TRalpha and TRbeta genotypes was determined for metamorphic and non metamorphic offspring from backcrosses between Ambystoma mexicanum (an obligate metamorphic-failure species) and metamorphic F1 hybrids (A. mexicanum x A. tigrinum tigrinum). The segregation of TR genotype was independent of the expression of life cycle mode phenotype, and neither TR locus was linked to DNA markers that flank a major-effect locus for life cycle mode. In the second experiment, a portion of the ligand-binding domain of TRalpha and TRbeta was cloned and sequenced for DNA samples from 14 different ambystomatid salamander populations, including obligate metamorphic, facultative metamorphic, and obligate metamorphic-failure taxa. Nucleotide sequence variation was found for both TRalpha and TRbeta, with several nonsynonomous substitutions that presumably code for nonconservative amino acid replacements. However, no general relationship was found between TR allelic variation and life cycle mode among populations or species. These data do not implicate TRs as candidate loci involved in the current maintenance or past evolution of alternate life cycle modes in members of the tiger salamander complex.

Alleles↗

The rhetoric vs. the reality in child care and protection: ideology and practice in working with fathers.

Within child care and protection, practitioners can be paralysed by a fundamental gap between the rhetoric and the reality in engaging fathers in their children's care. In an earlier paper we argued that there is a lack of an effective framework to guide practice with fathers in child care and protection work. We examined how health visitors and social workers could begin to assess how fathers could be categorized as either (or both) a risk or an asset to the child. Based on a review of the literature we now explore the limitations of current models of practice and trace the theoretical strands that influence them, drawing from the legal framework, attachment theory and models for anti-oppressive practice. We then highlight messages for practice with fathers for health care professionals involved in child protection. The working context for this paper is Scotland, although we believe that the ideas may be extrapolated to other geographical areas.

Adult↗

Hidden on the ward: the abuse of children in hospitals.

Hidden on the ward: the abuse of children in hospitals While there have been a small number of high profile cases of the abuse of children by hospital staff, there has been relatively little attention paid to the child protection issues for children staying in hospitals. Drawing on a conceptual framework from work on institutional abuse, we identify three types of abuse: physical and sexual abuse; programme abuse; and system abuse. Physical and sexual abuse can be perpetrated by medical professionals and hospital workers, it can be perpetrated by other children, or it can be perpetrated by the child's own parent(s). Research evidence from the United States of America (USA) suggests that the rate of abuse in hospitals is higher than in the family home. Programme abuse occurs when treatment and care falls below normally accepted standards. Recently, a tragic case of programme abuse concerned the unacceptably high death rate of babies undergoing heart surgery at Bristol Royal Infirmary. System abuse is the most difficult to define but concerns the way in which child health services fail to meet the needs of children. Recent reports have highlighted inadequate services for children and young people, lack of priority given to children's services, and geographical inequalities in the provision of services. Three crucial aspects in safeguarding children from abuse are highlighted: listening to children; the selection support and training of staff; and external systems of inspection, monitoring and standards. The recent British government agenda which has placed quality at the centre of National Health Service (NHS) developments are discussed. Only by addressing the abuse of children in hospital openly and honestly will effective child protection be possible.

Child↗

Men living with diabetes: minimizing the intrusiveness of the disease.

In this paper we present the findings from the second of four Participatory Action Research (PAR) groups with men and women who have been diagnosed with type two diabetes. The findings of the men's group are reported here. People who have received a diagnosis of diabetes must immediately absorb a great deal of information about how to control their diabetes, care for themselves and make lifestyle changes. In this study, we have asked men about this transition and about what it is like to live with diabetes. We aimed to understand how people with type two diabetes incorporate chronic illness into their lives. Utilizing the processes of PAR, we created a conducive environment for the voices of people with diabetes to be clearly heard in relation to their health. Men who live with type two diabetes met with a researcher and two Clinical Nurse Consultants, for two hours, once a week, for four weeks, during November 1998. The men expressed that diabetes had made a positive impact on their lifestyle; they viewed diabetes as part of life and not as an illness. Men chose foods with confidence; their concern about potential complications meant they chose to take better care of themselves. They were confident in their knowledge of diabetes, and while they took responsibility for themselves, being supported by their partner was helpful in managing their diabetes. They managed their life with diabetes by minimizing the intrusiveness of the disease.

Adaptation, Psychological↗

Complications of treatment with local field external beam radiotherapy for localized prostate cancer.

We performed this analysis to document the rate and severity of complications both during and after local field irradiation for localized prostate cancer and to assess the influence of three-dimensional conformal radiation therapy (3DCRT) on these complications. Bowel, urinary and cutaneous toxicities were noted in all patients treated with primary radiotherapy (RT) for prostate cancer using Radiation Therapy Oncology Group/European Organization for Research on Treatment of Cancer scores. Evaluations were performed weekly during RT, 6 weeks after RT and 3 monthly thereafter. Data on 111 were analysed. We also compared the complications of conventional and 3DCRT. The serious complication rates identified in this study compare favourably with those reported in the literature. Only 3.6%, 0.8% and 0% had acute grade 3 or 4 urinary, bowel or skin reactions respectively. Only two patients had chronic grade 3 or 4 urinary complications. Thus far no patients have developed chronic bowel or skin complications greater than grade 2. Despite dose escalation from 66 Gy to 70 Gy (with 3DCRT), there was a trend towards reduced toxicity when 3DCRT was compared with conventional radiation. RT is a well-tolerated treatment for early stage carcinoma of the prostate and our complication rates are compatible with international experiences. Further follow-up is required to determine the efficacy of treatment, the incidence of impotence and the final number of late complications.

Adenocarcinoma↗