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At least 1,747 records · Page 97Linked to original sources
PubMed2003

Neural circuitry underlying pain modulation: expectation, hypnosis, placebo.

The ability to predict the likelihood of an aversive event is an important adaptive capacity. Certainty and uncertainty regarding pain cause different adaptive behavior, emotional states, attentional focus, and perceptual changes. Recent functional neuroimaging studies indicate that certain and uncertain expectation are mediated by different neural pathways-the former having been associated with activity in the rostral anterior cingulate cortex and posterior cerebellum, the latter with activation changes in the ventromedial prefrontal cortex, mid-cingulate cortex and hippocampus. Expectation plays an important role not only in its modulation of acute and chronic pain, but also in other disorders which are characterized by certain expectation (specific phobias) or uncertain expectation (generalized anxiety disorder) of aversive events.

Journal Article↗
PubMed2001

Evolutionary history conditions the timing of transmission in vesicular stomatitis virus.

It has been postulated that early transmitted viruses would evolve to be more virulent than late transmitted ones. The reason for this prediction is that early transmission selects for rapid viral replication and, consequently, rapid host death, whereas late transmission would select for slow-replicating viruses that permit longer survival to the host. To test this prediction, experimental lineages of vesicular stomatitis virus (VSV) had been adapted to three different transmission dynamics during more than 100 generations. Transmission dynamic differed in the stage of infection at which transmission took place: early, intermediate or late. Regardless the timing of transmission imposed during the competition experiments done for estimating fitness, lineages adapted to an intermediate time of transmission reached higher fitness than viruses adapted to either early or late transmission. Viruses adapted to early and late transmission schedules showed a trade-off in their performance at other transmission times, with higher fitness at their own transmission time than at any other. The basis of fitness differences, in terms of growth parameters, have also been explored. Fitness correlated with the rate of growth and with the moment of maximum population density but not with the maximum density itself. In addition, a positive correlation between virus performance at late transmission and stability outside the cellular host has been detected.

Biological Evolution↗
PubMed2003

Capillary isoelectric focusing-based multidimensional concentration/separation platform for proteome analysis.

An integrated proteome concentration/separation approach involving on-line combination of capillary isoelectric focusing (CIEF) with capillary reversed-phase liquid chromatography (CRPLC) is developed for providing significant analyte concentration and extremely high resolving power toward protein and peptide mixtures. Upon completion of analyte focusing, the self-sharpening effect greatly restricts analyte diffusion and contributes to analyte stacking in narrowly focused bands with a concentration factor of approximately 240. In addition to analyte focusing, CIEF as the first separation dimension resolves proteins/peptides on the basis of their differences in pI and offers greater resolving power than that achieved in strong cation exchange chromatography. The grouping of two highly resolving and completely orthogonal separation techniques of CIEF and CRPLC, together with analyte focusing and concentration, significantly enhances the dynamic range and sensitivity of conventional mass spectrometry toward the identification of low-abundance proteins. The CIEF-based multidimensional separation/concentration platform enables the identification of a greater number of yeast soluble proteins than methods presented in the literature, yet requires a protein loading of only 9.6 microg. This protein loading is 2-3 orders of magnitude lower than those employed by the reported non-gel-based proteome techniques. The distribution of a codon adaptation index value for identified yeast proteins approximates to that predicted for the entire yeast proteome and supports the capability of CIEF-based proteome separation technology for achieving comprehensive proteome analysis. By reducing the inner diameter of chromatography columns from 180 microm to 100 microm, the required protein loading is further decreased from 9.6 microg to 960 ng, illustrating the potential usage of this proteome technology for the analysis of protein profiles within small cell populations or limited tissue samples.

Chromatography, Liquid↗
PubMed2001

Stress in UK families conducting intensive home-based behavioral intervention for their young child with autism.

There is increasing international interest in intensive home-based behavioral intervention for children with autism. In the present study, 141 UK parents conducting such interventions completed a questionnaire addressing issues of stress, coping, and support. Regression analyses showed that parents' stress levels were predicted mainly by psychological rather than demographic variables. In particular, adaptive coping strategies, informal social support sources, and beliefs about the efficacy of the intervention were associated with lower reported stress and higher levels of autism symptomatology were associated with higher reported stress. There was also evidence that the use of Passive Appraisal coping and beliefs about the efficacy of the interventions moderated the effects of autism symptomatology on parents' pessimism. Implications of these findings for future research and for the support of families engaged in intensive home-based behavioral intervention are discussed.

Adaptation, Psychological↗
PubMed1990

Stress, intrusive imagery, and chronic distress.

Discusses the nature of stress in the context of problems with its definition and sources of confusion regarding its usefulness and specificity. Stress can be defined as a negative emotional experience accompanied by predictable biochemical, physiological, and behavioral changes that are directed toward adaptation either by manipulating the situation to alter the stressor or by accommodating its effects. Chronic stress is more complex than most definitions suggest and is clearly not limited to situations in which stressors persist for long periods of time. Responses may habituate before a stressor disappears or may persist long beyond the physical presence of the stressor. This latter case, in which chronic stress and associated biobehavioral changes outlast their original cause, is considered in light of research at Three Mile Island and among Vietnam veterans. The role of intrusive images of the stressor or uncontrollable thoughts about it in maintaining stress is explored.

Accidents↗
PubMed2003

Family and legal indicators of child adjustment to divorce among families with young children.

This research used structural equation modeling to examine relations among family dynamics, attorney involvement, and the adjustment of young children (0-6 years) at the time of parental separation. The article presents baseline data (N = 102 nonresidential fathers and N = 110 primary caretaking mothers) from a larger longitudinal study. Results showed that the effects of parental conflict on child outcomes were mediated by paternal involvement, the parent-child relationship, and attorney involvement. A scale assessing parental gatekeeping yielded two significant factors: Spouse's Influence on Parenting and Positive View of Spouse. Paternal involvement was related to children's adaptive behavior, whereas negative changes in parent-child relationships predicted behavior problems. Mothers who experienced greater psychological symptomatology were less likely to utilize an attorney, which in turn predicted greater internalizing problems in their children.

Adolescent↗
PubMed2004

Parent functioning in families of preadolescents with spina bifida: longitudinal implications for child adjustment.

The purpose of this study was to test a strength-of-association model regarding possible longitudinal and bidirectional associations between parent functioning and child adjustment in families of children with spina bifida (n = 68) and families of able-bodied children (n = 68). Parent functioning was assessed across 3 domains: parenting stress, individual psychosocial adjustment, and marital satisfaction. Child adjustment was indexed by teacher-reported internalizing and externalizing symptoms, self-reported depressive symptoms, and observed adaptive behavior. Findings revealed that all 3 parent functioning variables predicted child adjustment outcomes, and that such results were particularly strong for externalizing symptoms. Associations between parent functioning and child adjustment tended to be in the direction of parent to child and were similar across both groups. These findings have implications for potential interventions targeted at helping families manage the transition into early adolescence in families of children with spina bifida as well as families of healthy children.

Adjustment Disorders↗
PubMed2003

QT dynamicity and sudden death after myocardial infarction: results of a long-term follow-up study.

INTRODUCTION: The aim of this study was to determine whether impaired adaptation of the QT interval to changes in heart rate predicts sudden death after an acute myocardial infarction. METHODS AND RESULTS: The Groupe d'Etude du Pronostic de l'Infarctus du Myocarde (GREPI) trial was a prospective multicenter study designed to evaluate the long-term outcome of myocardial infarction. QT dynamicity was evaluated in 265 patients by analyzing 24-hour Holter recordings obtained 9 to 14 days after myocardial infarction. The linear regression slope of QT intervals measured to the apex and to the end of the T wave (QTe) plotted against RR intervals was calculated using a dedicated Holter algorithm. The value of QT/RR in predicting sudden death and total mortality was compared with those of ejection fraction, heart rate variability, and late potentials. Mean follow-up was 81 +/- 27 months. There were 73 deaths, of which 23 were sudden. Of all the parameters, an increased diurnal QTe/RR slope (>0.18) was the strongest independent predictor of sudden death (relative risk 6.07, confidence interval 1.48-24.95, P = 0.01). CONCLUSION: Increased diurnal QTe dynamicity is independently predictive of sudden death among patients with myocardial infarction. This simple parameter may help to stratify risk and select patients who may benefit from antiarrhythmic prophylaxis.

Aged↗
PubMed2004

Dimensional reduction for a Bayesian filter.

An adaptive strategy is proposed for reducing the number of unknowns in the calculation of a proposal distribution in a sequential Monte Carlo implementation of a Bayesian filter for nonlinear dynamics. The idea is to solve only in directions in which the dynamics is expanding, found adaptively; this strategy is suggested by earlier work on optimal prediction. The construction should be of value in data assimilation, for example, in geophysical fluid dynamics.

Journal Article↗
PubMed1999

The team meeting on a rapid turnover psychiatric ward: clinical illustration of a model for stages of group development.

This article illustrates stages of group development in a semi-structured team meeting of staff and patients in an inpatient psychiatric unit. Clinical material drawn from such a group at the Massachusetts Mental Health Center is presented in support of the view that, even in a rapid-turnover ward, group process in a mixed-level, mixed-diagnosis "ward meeting" follows some predictable lines and responds to the articulation of certain predictable concerns. Garland's (1981) model of group development is adapted to show the cyclical nature of group process in a teaching hospital, where doctors as well as patients may make only brief stays. Effective leadership strategies are suggested.

Group Processes↗
PubMed2004

Athens 2004: the pollution climate and athletic performance.

Athens sits in a basin approximately 450 km2 in area, surrounded by mountains and open sea. Anthropogenic emissions in conjunction with the topographical and meteorological conditions can result in high air pollution within the city. The pollutants of concern for athletes competing in Athens 2004 appear to be nitrogen dioxide (NO2), ozone and particulate (PM10) pollution. Exposure to elevated ozone concentrations has been reported to give rise to symptoms that include cough, chest pain, difficulty in breathing, headache, eye irritation and a decrease in forced expiratory volume in one second. All of these effects are likely to impact upon performance, and several studies of cyclists suggest this to be the case. In contrast, the impact of ambient concentrations of NO2 appears to be negligible on normal activities, but at high exercise intensities the impact remains unclear. The use of currently available information and models to predict the effect of ozone and other pollutants on elite athletes is problematical, since such models are based upon significantly lower ventilation rates than those achieved by some elite athletes. In addition, it is already known that the response to ozone can vary somewhat between individuals. Since the individuals who will be competing in Athens are physiologically very different to the participants in most published studies, it is difficult to predict individual responses. There is some evidence to indicate that adaptation to the adverse health and performance effects of ozone can occur, so that performance is partially recovered on re-exposure. The adaptation is not seen in all studies and appears to be dependent on several factors, including the initial sensitivity of the individual to ozone. Antioxidant supplementation has also been shown in some studies to partially ameliorate the adverse effects of ozone by counteracting the oxidative stress mechanism associated with this pollutant. Whether this transfers to performance enhancement per se remains unclear at present. Additional research is required to gain a sound understanding of the effects of a complex mixed air pollution exposure on the pulmonary function and performance of athletes exercising at high work intensities.

Air Pollutants↗
PubMed1996

Outcomes measurement: health-related quality of life.

Outcomes research is rapidly expanding and evolving in the assessment of medical treatment and has significant potential contributions to the assistive technology field. Over the past two decades, numerous instruments have been developed and are widely used to collect data for evaluating the efficacy and effectiveness of traditional medical interventions. Although this methodology may not transfer seamlessly to assistive technology, the basis of its instrumentation and many of its concepts are highly relevant. Many current and emerging medical and assistive technology interventions are vigorously advocated but have inadequately demonstrated their positive impact on outcome. A key concept used in medical technology outcomes measurement is health-related quality of life, which represents the functional effect of an illness and its consequent therapy as perceived by the individual receiving treatment. People tend to make decisions about alternative health care services by estimating the effects of an intervention on outcomes important to themselves, by comparing intervention benefits and harms and by deciding whether the outcomes are worth the costs. Numerous valid, reliable, and responsive health-related quality of life instruments are available and are designed to discriminate between individuals, to evaluate change over time, or to predict outcome. Many are worth examining for potential use or adaptation in assistive technology outcomes measurement. Some of these instruments are generic, some specific, and others deal with health state preference. Generic health-related quality of life instruments are broadly applicable across various diseases, conditions, or populations. Specific instruments focus on a given disease, condition, or population. Health state preference instruments assess an individual's desirability for a given health state or outcome. Assistive technology practitioners claim that they improve the quality of life for the individuals they serve. Health-related quality of life must then be considered an integral component of the evaluation of service effectiveness. This paper reviews the concepts and instrumentation used in medical technology assessment for consideration and potential application in assistive technology measurement.

Health Services Research↗
PubMed2004

Epidemiological and genetic correlates of incident Chlamydia trachomatis infection in North American adolescents.

Epidemiological and genetic correlates of Chlamydia trachomatis infection were examined prospectively in 124 male and 361 female adolescents at high risk for human immunodeficiency virus type 1 (HIV-1) infection. Seventy percent of subjects were African American, and 68% had HIV-1 infection. As expected, younger age (<17 years), multiple sex partners (> or =2), and prior chlamydial infection predicted chlamydial infection during a 6-56-month follow-up period (P=.02, P=.02, and P=.03, respectively). Human leukocyte antigen (HLA) class II variant DQB1*06 (mostly *0602 and *0603) was associated with chlamydial infection (49% vs. 34%; adjusted relative odds [RO], 1.8; P=.005), as was HLA class I haplotype B*44-Cw*04 (10% vs. 4%; RO, 3.2; P=.009). DQB1*06 was found in 9 (75%) of 12 female adolescents with chlamydial pelvic inflammatory disease. In contrast, sex, ethnicity, and HIV-1 infection did not predict chlamydial infection. These findings suggest that antigen presentation in adaptive immune responses may serve as a major factor in effective control of C. trachomatis infection. The underlying mechanisms remain to be experimentally elucidated.

Adolescent↗
PubMed2006

Nonrandom mating preserves intrasexual polymorphism and stops population differentiation in sexual conflict.

Evolutionary conflict between the sexes is predicted to lead to sexual arms races in which male adaptations for acquiring mates ("offense" traits) are met by female counteradaptations--for example, to reduce mating rate ("defense" traits). Such coevolutionary chases may be perpetual. However, we show here that the coevolutionary process may also lead to a stable state in which multiple offense-defense trait pairs are maintained. This type of polymorphism below the species level is a result of sexual conflict in combination with nonrandom mating. Our results show that if nonrandom mating occurs with respect to male and female conflict traits, genetic correlations will act to stabilize the trait frequencies so that all morphs are maintained. We discuss the results in special relation to the evolution of female polymorphism in diving beetles and argue that the process we describe may be a general force that maintains polymorphism in other taxa as well.

Animals↗
PubMed2005

Proceedings of the SMBE Tri-National Young Investigators' Workshop 2005. What is the role of genome duplication in the evolution of complexity and diversity?

Gene and genome duplications provide a source of genetic material for mutation, drift, and selection to act upon, making new evolutionary opportunities possible. As a result, many have argued that genome duplication is a dominant factor in the evolution of complexity and diversity. However, a clear correlation between a genome duplication event and increased complexity and diversity is not apparent, and there are inconsistencies in the patterns of diversity invoked to support this claim. Interestingly, several estimates of genome duplication events in vertebrates are preceded by multiple extinct lineages, resulting in preduplication gaps in extant taxa. Here we argue that gen(om)e duplication could contribute to reduced risk of extinction via functional redundancy, mutational robustness, increased rates of evolution, and adaptation. The timeline for these processes to unfold would not predict immediate increases in species diversity after the duplication event. Rather, reduced probabilities of extinction would predict a latent period between a genome duplication and its effect on species diversity or complexity. In this paper, we will develop the idea that genome duplication could contribute to species diversity through reduced probability of extinction.

Animals↗
PubMedDate not supplied

The concept of closure in calculating carbon balance of forests: accounting for differences in spatial and temporal scales of component processes.

The concept of closure, which has been used extensively to calculate the heat and water budgets of forests, has led to advances in the understanding of how heat and water balances are controlled. The successful construction of closed heat and water budgets of forests can be attributed to the large scale of input and output fluxes relative to changes in storage, the comparative ease with which such fluxes can be measured, and the regularity with which forests cycle through discharge and recharge on diurnal and annual cycles. The applicability of simple, closed budget analysis for carbon balance of forests is less certain because changes in internal storage, which are of major significance, occur at different time scales for growth and decomposition. We conclude that carbon balance might best be modeled as an open system. For long-term predictions, the most important processes to consider are acclimation and adaptation, which occur at different spatial and temporal scales. Construction of a modeling procedure to accommodate this variation is discussed.

Journal Article↗
PubMed2001

Intraindividual comparative animal study of alpha- and beta-tricalcium phosphate degradation in conjunction with simultaneous insertion of dental implants.

An intraindividual comparative study of proximal tibial marrow defects in nine adult Goettinger miniature pigs (GMPs) was undertaken. The left side of the defect was filled with granular beta-tricalcium phosphate (TCP) ceramic ad modum Cerasorb, and the right side was filled with granular alpha-TCP ceramic ad modum Biobase alpha pore. Simultaneously, dental screw implants were inserted in each ceramic and fixed within the orthotopically replanted corticalis lids. Control defects were made in two other animals. The survival period ranged from 4 to 86 weeks (control study, 16 and 20 weeks). The reorganization and degree of bone regeneration, dynamics of ceramic degradation, and remodeling characteristics of the bone regenerate referring to osseo-integration of the dental implants were examined histomorphologically in nondecalcified specimens. The results reveal that both ceramic types were osteoconductive exclusively. Centripetally oriented angiogene bone regeneration occurred at the margins of the circular defects. Ceramic degradation was performed hydrolytically and within cells. Furthermore, it was demonstrated that decomposition of the intratrabecularly integrated ceramic residues underlies a dynamic process of degradation. Within 86 weeks, nearly 80% to 90% of the larger alpha-TCP granules, and nearly 90% to 95% of the beta-TCP granules were degraded. At this time, especially for the alpha-TCP modification, ceramic microparticles were found in the marrow, either unbound or within polynuclear macrophages. The predictable degradation of both ceramic types provides an early functional adaptation of bone regenerates and facilitates a biofunctional, anisotropic orientation of the neotrabeculae without delay. It is concluded that because of the initially pronounced accumulation of macrophages, dental implants should not be inserted simultaneously with ceramic, but after further progress of ceramic degradation (5 to 6 months after TCP implantation).

Absorbable Implants↗
PubMed2002

Executive control function in psychiatric and medical illness.

Executive Control Function (ECF) is the ability to plan, sequence, and monitor one's behavior in order to accomplish a given goal while simultaneously exercising cognitive flexibility to adapt to changing task requirements. Multiple studies demonstrate that ECF predicts functional outcome, level of care required, and work potential for both well and ill populations. However, clinicians often do not routinely assess ECF during mental status evaluations because of the perceived lack of practical bedside tests. This review article discusses the major neuropsychological measures used to probe for impairment, with special emphasis on those that are easily administered at the patient's bedside. The current literature on executive dysfunction in psychiatric and medical illness is reviewed. The neuroanatomy and neurochemistry of ECF is also reviewed, with emphasis on structural dysfunction in specific illnesses. Finally, various treatment options, both pharmacological and psychotherapeutic, are discussed.

Journal Article↗