Search PubMed⌕ Search

Biomedical subjects

S E Taylor

Publications and source records attributed to S E Taylor.

At least 37 records · Page 2Linked to original sources

Biobehavioral responses to stress in females: tend-and-befriend, not fight-or-flight.

The human stress response has been characterized, both physiologically and behaviorally, as "fight-or-flight." Although fight-or-flight may characterize the primary physiological responses to stress for both males and females, we propose that, behaviorally, females' responses are more marked by a pattern of "tend-and-befriend." Tending involves nurturant activities designed to protect the self and offspring that promote safety and reduce distress; befriending is the creation and maintenance of social networks that may aid in this process. The biobehavioral mechanism that underlies the tend-and-befriend pattern appears to draw on the attachment-caregiving system, and neuroendocrine evidence from animal and human studies suggests that oxytocin, in conjunction with female reproductive hormones and endogenous opioid peptide mechanisms, may be at its core. This previously unexplored stress regulatory system has manifold implications for the study of stress.

Adaptation, Psychological↗

Polymorphism and interactions of a viral fusion peptide in a compressed lipid monolayer.

With a view toward possible new insights into viral fusion mechanisms, we have investigated the HIV-1 gp41 fusion peptide in a monomolecular film of the biomembrane lipid palmitoyloleoylphosphatidylcholine. Its surface activity at an air/water interface was measured under equilibrium conditions, using the conventional Langmuir trough technique. Through a novel thermodynamic analysis, the partial molecular area of the peptide in the lipid moiety could be determined as a function of the lateral pressure and the interfacial peptide/lipid ratio. This indicates an orientation of the peptide backbone parallel to the lipid hydrocarbon tails. The molecular area decreases significantly upon monolayer compression, suggesting a conformational transition from a somewhat compact configuration to a more extended, presumably beta-strand structure when a lipid packing density is approached that is generally believed to mimic the physical state of a biological membrane. Up to a lateral pressure of approximately 15 mN/m, practically all peptide inserts into the lipid monolayer. At higher compression a distinct partitioning into the aqueous subphase is observed. Under these conditions the data also reflect a strong aggregation of the lipid-associated peptide. Beyond a critical peptide/lipid ratio, the peptide's area requirement was found to become substantially enhanced, possibly because of the formation of water-filled pores.

Amino Acid Sequence↗

Negative HIV-specific expectancies and AIDS-related bereavement as predictors of symptom onset in asymptomatic HIV-positive gay men.

This study examined negative HIV-related expectancies, AIDS-related bereavement, and the interaction of expectancies and bereavement as predictors of the onset of significant HIV-related symptoms among previously asymptomatic HIV-positive gay men. From a longitudinal psychobiological investigation, 72 men were selected who had been HIV-positive and asymptomatic from study entry (approximately 3 years). Participants were followed for an additional 2 1/2 to 3 1/2 years after psychosocial assessment, with symptom status assessed every 6 months. The interaction of negative HIV-specific expectancies and bereavement was a significant predictor of symptom onset. Negative HIV-specific expectancies predicted the subsequent development of symptoms among bereaved men, controlling for immunological status, use of zidovudine, high-risk sexual behavior, substance use, and depression.

Acquired Immunodeficiency Syndrome↗

Preemptive pharmacologic intervention in radiation-induced salivary dysfunction.

Xerostomia ("dry mouth") is a symptom of several diseases. It also occurs as a side effect of certain therapeutic interventions, most frequently pharmacotherapy. The most severe and irreversible forms of salivary dysfunction result from damage to or loss of salivary acinar cells. One of the severest forms of iatrogenic salivary gland destruction results from the therapeutic doses of irradiation given to treat head and neck cancer or to purge the bone marrow before transplantation. Xerostomia encompasses a wide range of involvement, from an inconvenience when mild, to a debilitating condition when severe. Reports of the symptom of dry mouth by patients do not always correlate with the degree of diminished salivary flow. However, a significant loss of stimulated flow makes it difficult to process solid food into a bolus that can be swallowed. If sustained, nutritional deficiencies may result. Saliva also facilitates formation of speech patterns. Its loss hinders speaking and communicating, possibly causing the patient to withdraw from social interaction. Together these conditions can impair the physiological and psychological well-being of the patient. Thousands of individuals undergo radiation therapy for head and neck cancer in the United States each year. Increasing numbers are receiving total body radiation before transplantation of bone marrow. Although the salivary gland is not one of the more actively dividing organs in the body, nevertheless it ranks as one of the most radiosensitive. The mechanism of this sensitivity is not understood. This article reviews human and animal pathophysiology of radiation-induced salivary damage. We also discuss animal studies that have employed various strategies to modify and clarify this process. Finally, we describe encouraging results from early clinical trials suggesting that protection of salivary glands during therapeutic irradiation may be possible.

Adrenergic beta-Agonists↗

Psychosocial resources and the SES-health relationship.

Psychosocial resources, which include optimism, coping style, a sense of mastery or personal control, and social support, influence the relationship between SES and health. To varying degrees, these resources appear to be differentially distributed by social class and related to health outcomes. Such resources may partially mediate the impact of SES on health. For example, environments that undermine personal control may have an impact on chronic arousal and the corresponding development of disease, such as CHD. Psychosocial resources may also moderate the impact of SES on health. For example, a large number of positive social relationships and a few conflictual ones may buffer individuals against the adverse effects of SES-related stress. These psychosocial resources are moderately intercorrelated, and so a research strategy that explores their coherence as a psychosocial profile that promotes resilience to stress is tenable and merits empirical examination. The erosion of these resources as one moves lower on the SES scale and specific factors that contribute to such erosion are discussed.

Adaptation, Psychological↗

Sodium TQF NMR and intracellular sodium in isolated crystalloid perfused rat heart.

The feasibility of monitoring intracellular sodium changes using Na triple quantum filtered NMR without a chemical shift reagent (SR) was investigated in an isolated rat heart during a variety of interventions for Na(i) loading. Perfusion with 1 mM ouabain or without K+ present in the perfusate for 30 min produced a rise of the Na TQF signal with a plateau of approximately 190% and approximately 228% relative to the preintervention level, respectively. Stop-flow ischemia for 30 min resulted in a TQF signal growth of approximately 147%. The maximal Na TQF signal increase of 460% was achieved by perfusion without K+/Ca2+, corresponding to an elimination of the Na transmembrane gradient. The observed values of Na NMR TQF growth in the physiological and pathological ranges are in agreement with reported data by other methods and have a linear correlation with intracellular sodium content as determined in this study by Co-EDTA method and by sucrose-histidine washout of the extracellular space. Our data indicate that the increase in Na TQF NMR signal is determined by the growth of Na(i), and the extracellular Na contribution to the total TQF signal is unchanged at approximately 64%. In conclusion, Na TQF NMR without using SR offers a unique and noninvasive opportunity to monitor alterations of intracellular sodium. It may provide valuable insights for developing cardioprotective strategies and for observing the effects of pharmaceutical treatments on sodium homeostasis.

Animals↗

Treatment options for chronic prostatitis due to vancomycin-resistant Enterococcus faecium.

Prostatitis due to vancomycin-resistant enterococci has not been previously described. Reported here is a case of chronic prostatitis due to Enterococcus faecium, resistant to vancomycin, ampicillin, ciprofloxacin and doxycycline, in a 42-year-old liver transplant recipient. Treatment with a combination of rifampin and nitrofurantoin for 6 weeks resulted in long-lasting cure. Other antimicrobial agents active in vitro against vancomycin-resistant enterococci, such as quinupristin/ dalfopristin and chloramphenicol, are unlikely to achieve sufficient prostatic tissue levels to be successfully utilized for treatment of this condition.

Adult↗

Model for using hip-hop music for small group HIV/AIDS prevention counseling with African American adolescents and young adults.

Currently little attention has been directed, with the exception of peer education efforts, to constructively develop new and innovative ways to promote HIV/AIDS primary prevention among African American (AA) adolescents and young adults. With this in mind, the aim of this conceptual effort is to present a HIV/AIDS preventive counseling protocol developed for use with AA young adults that makes use of hip-hop music, a form of music popularized by young AAs. The author contend that an increased understanding of the relationships that many AA young adults have with hip-hop music may be used by disease prevention personnel to educate these populations about protective factors for HIV. Making use of hip-hop music is one strategy for integrating counseling in prevention and health maintenance. The overall implications of using hip-hop music in health promotion are unlimited. First, this method makes use of cultural relevant materials to address the educational and health needs of the target community. Second, it is grounded in an approach that serves to stimulate cooperative learning based on peer developed content. Moreover, the use of this medium can be applied to other health promotion activities such as violence/harm reduction and substance abuse prevention, upon reviews of songs for appropriate content. The authors contend that such an approach holds heuristic value in dealing with HIV/AIDS prevention among AA young adults. Additional testing of the intervention is warranted in the refinement of this innovative intervention.

Acquired Immunodeficiency Syndrome↗

Harnessing the imagination. Mental simulation, self-regulation, and coping.

Mental simulation provides a window on the future by enabling people to envision possibilities and develop plans for bringing those possibilities about. In moving oneself from a current situation toward an envisioned future one, the anticipation and management of emotions and the initiation and maintenance of problem-solving activities are fundamental tasks. In the program of research described in this article, mental simulation of the process for reaching a goal or of the dynamics of an unfolding stressful event produced progress in achieving those goals or resolving those events. Envisioning successful completion of a goal or resolution of a stressor--recommendations derived from the self-help literature--did not. Discussion centers on the characteristics of effective and ineffective mental simulations and their relation to self-regulatory processes.

Adaptation, Psychological↗

Cognitive processing, discovery of meaning, CD4 decline, and AIDS-related mortality among bereaved HIV-seropositive men.

This study investigated whether finding meaning in response to an HIV-related stressor was associated with changes in immune status and health. Forty HIV-seropositive men who had recently experienced an AIDS-related bereavement completed interviews assessing cognitive processing and finding meaning after the loss and provided blood samples for a 2- to 3-year follow-up. AIDS-related mortality over an extended follow-up was determined from death certificates. As predicted, men who engaged in cognitive processing were more likely to find meaning from the loss. Furthermore, men who found meaning showed less rapid declines in CD4 T cell levels and lower rates of AIDS-related mortality (all ps < .05), independent of health status at baseline, health behaviors, and other potential confounds. These results suggest that positive responses to stressful events, specifically the discovery of meaning, may be linked to positive immunologic and health outcomes.

Acquired Immunodeficiency Syndrome↗

Optimism is associated with mood, coping, and immune change in response to stress.

This study explored prospectively the effects of dispositional and situational optimism on mood (N = 90) and immune changes (N = 50) among law students in their first semester of study. Optimism was associated with better mood, higher numbers of helper T cells, and higher natural killer cell cytotoxicity. Avoidance coping partially accounted for the relationship between optimism and mood. Among the immune parameters, mood partially accounted for the optimism-helper T cell relationship, and perceived stress partially accounted for the optimism-cytotoxicity relationship. Individual differences in expectancies, appraisal, and mood may be important in understanding psychological and immune responses to stress.

Adaptation, Psychological↗

Estimating glucose metabolism using glucose analogs and two tracer kinetic models in isolated rabbit heart.

The purpose of this investigation was to 1) evaluate the relative accuracy of the Sokoloff and Patlak tracer kinetic models in estimating glucose metabolic rate (GMR) in the presence and absence of insulin; 2) evaluate the effect of nutritional state on the lumped constant (LC); and 3) compare the kinetics of 2-fluoro-2-deoxy-D-[14C]glucose (FDG) and 2-deoxy-D-[3H]glucose (DG) membrane transport and phosphorylation. The experimental preparation was the isolated, red blood cell-albumin-perfused rabbit heart. Our results showed that both tracer kinetic models provided GMR estimates that correlated well with the Fick method (for FDG, R = 0. 84 and 0.91 for the Sokoloff and Patlak models, respectively); nutritional state did not affect the LC; and FDG and DG have different transport and/or phosphorylation parameters. We also observed that 1) the addition of a fourth compartment to the Sokoloff model reduced the mean squared error between measured and modeled data by a factor of 7.4; 2) a longer time (21.8 min) was required to obtain a linear phase of the Patlak plot than is allowed in clinical studies; and 3) accurate GMR estimates were obtained only by using different LCs reflecting insulin's presence or absence. Our results indicate potential sources of error in the use of FDG and positron emission tomography to quantify GMR in patients.

Animals↗

The molecular area characteristics of the HIV-1 gp41-fusion peptide at the air/water interface. Effect of pH.

The putative fusion peptide of HIV-1 is a highly surface active substance. Relevant measurements with the Langmuir monolayer technique have been carried out for a broad range of the pH in the aqueous subphase. The data are processed towards a quantitative analysis of the partitioning equilibrium between the interfacial and aqueous moieties. Our results reveal a pronounced decrease of the surface area per peptide molecule upon monolayer compression. This phenomenon could be interpreted in terms of an orientational transition experienced by an alpha-helical peptide structure. The area requirements at any fixed lateral pressure pass through a distinct minimum at a pH of 5.5 (+/-0.5). Such an apparent isoelectric point was confirmed by isoelectric focusing of peptide aggregates. Accordingly a drastic drop of the pK-values of the two basic amino acid residues in comparison with an aqueous medium is indicated. It can be readily explained based on an inherent decrease of the effective dielectric constant. The observed low pH in favor of an enhanced surface affinity of the peptide may be a significant factor concerning its function as a fusion promoting agent.

Amino Acid Sequence↗

Social relationships and immune processes in HIV seropositive gay and bisexual men.

This three-year longitudinal study assessed the association between social relationships and human immunodeficiency virus (HIV) progression in individuals at risk for morbidity and mortality due to acquired immune deficiency syndrome (AIDS). Two-hundred five HIV seropositive men without AIDS completed measures of social integration and loneliness at baseline. Blood samples used to assess CD4 T-lymphocyte levels were collected at baseline and at six-month intervals for a three-year follow-up period. Contrary to expectation, lower levels of baseline loneliness predicted more rapid declines in CD4 levels over the follow-up period. This association was independent of baseline CD4 values, negative affect, and health practices. A series of mediational analyses revealed that sexual behavior, medication use, bereavement, coping, and a number of other variables were not mechanisms through which loneliness affected the immune system. Loneliness was not associated with time to AIDS diagnosis or time to AIDS-related mortality. These findings are consistent with the emerging view that social relationships can have deleterious, as well as protective, influences on health outcomes.

Acquired Immunodeficiency Syndrome↗