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PubMed1998

[Coping-oriented group therapy for patients with schizophrenic or schizoaffective disorders. An exploratory study].

The controlled study presented here was designed to examine the influence of the degree of structure of a coping-orientated therapy, the changes between the beginning and the end of therapy concerning satisfaction with therapy, psychopathology, attitude towards medication, coping behaviour and social variables, the effects on the days of hospitalisation within one year after the end of treatment and the relevant variables to predict the outcome twelve months later. It could be shown that patients in a relatively unstructured supportive group therapy wished to discuss topics that are very similar to those of coping-orientated therapy, that coping-orientated therapy results especially in an increase in knowledge about illness and treatment and that the therapeutic outcome after a one-year period can best be predicted by the degree of active coping strategies, social adaptation, trust in medication and cognitive variables.

Adaptation, Psychological↗
PubMed2000

Chaotic flow: the physics of species coexistence.

Hydrodynamical phenomena play a keystone role in the population dynamics of passively advected species such as phytoplankton and replicating macromolecules. Recent developments in the field of chaotic advection in hydrodynamical flows encourage us to revisit the population dynamics of species competing for the same resource in an open aquatic system. If this aquatic environment is homogeneous and well-mixed then classical studies predict competitive exclusion of all but the most perfectly adapted species. In fact, this homogeneity is very rare, and the species of the community (at least on an ecological observation time scale) are in nonequilibrium coexistence. We argue that a peculiar small-scale, spatial heterogeneity generated by chaotic advection can lead to coexistence. In open flows this imperfect mixing lets the populations accumulate along fractal filaments, where competition is governed by an "advantage of rarity" principle. The possibility of this generic coexistence sheds light on the enrichment of phytoplankton and the information integration in early macromolecule evolution.

Ecology↗
PubMed2003

The strength of persistent antigenic stimulation modulates adaptive tolerance in peripheral CD4+ T cells.

The quantitative adaptation of receptor thresholds allows cells to tailor their responses to changes in ambient ligand concentration in many biological systems. Such a cell-intrinsic calibration of T cell receptor (TCR) sensitivity could be involved in regulating responses to autoantigens, but this has never been demonstrated for peripheral T cells. We examined the ability of monoclonal naive T cells to modulate their responsiveness differentially after exposure to fourfold different levels of persistent antigen stimulation in vivo. T cells expanded and entered a tolerant state with different kinetics in response to the two levels of stimulation, but eventually adjusted to a similar slow rate of turnover. In vivo restimulation revealed a greater impairment in the proliferative ability of T cells resident in a higher antigen presentation environment. We also observed subtle differences in TCR signaling and in vitro cytokine production consistent with differential adaptation. Unexpectedly, the system failed to similarly compensate to the persistent stimulus in vivo at the level of CD69 expression and actin polymerization. This greater responsiveness of T cells residing in a host with a lower level of antigen presentation allows us to demonstrate for the first time an intrinsic tuning process in mature T lymphocytes, albeit one more complex than current theories predict.

Adaptation, Physiological↗
PubMed1999

Comprehensive mutation analysis of TSC1 and TSC2-and phenotypic correlations in 150 families with tuberous sclerosis.

Tuberous sclerosis (TSC [MIM 191090 and MIM 191100]) is an autosomal dominant disorder characterized by hamartomas in many organs. Two thirds of cases are sporadic and are thought to represent new mutations. TSC is caused by mutations affecting either of the presumed tumor-suppressor genes, TSC1 and TSC2. Both appear to function as tumor suppressors, because somatic loss or intragenic mutation of the corresponding wild-type allele is seen in the associated hamartomas. Here we report the first comprehensive mutation analysis of TSC1 and TSC2 in a cohort of 150 unrelated TSC patients and their families, using heteroduplex and SSCP analysis of all coding exons and using pulsed-field gel electrophoresis and conventional Southern blot analysis and long PCR to screen for large rearrangements. Mutations were characterized in 120 (80%) of the 150 cases, affecting TSC1 in 22 cases and TSC2 in 98 cases. TSC1 mutations were significantly underrepresented in sporadic cases (P=. 000185). Twenty-two patients had TSC2 missense mutations that were found predominantly in the GAP-related domain (eight cases) and in a small region encoded in exons 16 and 17, between nucleotides 1849 and 1859 (eight cases), consistent with the presence of residues performing key functions at these sites. In contrast, all TSC1 mutations were predicted to be truncating, consistent with a structural or adapter role for the encoded protein. Intellectual disability was significantly more frequent in TSC2 sporadic cases than in TSC1 sporadic cases (P=.0145). These data provide the first representative picture of the distribution and spectrum of mutations across the TSC1 and TSC2 loci in clinically ascertained TSC and support a difference in severity of TSC1- and TSC2-associated disease.

Blotting, Southern↗
PubMed2003

Shared control of epidemiological traits in a coevolutionary model of host-parasite interactions.

Most models concerning the evolution of a parasite's virulence and its host's resistance assume that each component of the relationship (transmission, virulence, recovery, etc.) is controlled by either the host or the parasite but not by both. We present a model that describes the coevolution of host and parasite, assuming that the rate of transmission or the virulence depends on both genotypes. The evolution of these traits is constrained by trade-offs that account for costs of defense and attack strategies, in line with previous studies on the separate evolution of the host and the parasite. Considering shared control by the host and the parasite in determining the traits of the relationship leads to several novel predictions. First, the host should evolve maximal investment in defense against parasites with an intermediate replication rate. Second, the evolution of the parasite strongly depends on the way the host's defense is described. Third, the coevolutionary process may lead to decreasing the parasite's virulence as a response to a rise in the host's background mortality, contrary to classical predictions.

Adaptation, Physiological↗
PubMed2006

The transcriptomics of ecological convergence between 2 limnetic coregonine fishes (Salmonidae).

Species living in comparable habitats often display strikingly similar patterns of specialization, suggesting that natural selection can lead to predictable evolutionary changes. Elucidating the genomic basis underlying such adaptive phenotypic changes is a major goal in evolutionary biology. Increasing evidence indicates that natural selection would first modulate gene regulation during the process of population divergence. Previously, we showed that parallel phenotypic adaptations of the dwarf whitefish (Coregonus clupeaformis) ecotype to the limnetic trophic niche involved parallel transcriptional changes at the same genes involved in muscle contraction and energetic metabolism relative to the sympatric normal ecotype. Here, we tested whether the same genes are also implicated in a limnetic specialist species, the cisco (Coregonus artedi), which is the most likely competitor of dwarf whitefish. Significant upregulation was detected in cisco at the same 6 candidate genes functionally involved in modulating swimming activity, namely 5 variants of a major protein of fast muscle and 1 putative catalytic crystallin enzyme. Moreover, 3 of 5 variants and the same putative catalytic crystallin enzyme were upregulated in cisco relative to the dwarf ecotype, indicating a greater physiological potential of the former for exploiting the limnetic trophic niche. This study provides the first empirical evidence that recent, parallel phenotypic evolution toward the use of the same ecological niche occupied by a specialist competitor involved similar adaptive changes in expression at the same genes. As such, this study provides strong support to the general hypothesis that directional selection acting on gene regulation may promote rapid phenotypic divergence and ultimately speciation.

Adaptation, Biological↗
PubMed2001

Bedsharing, temperament, and sleep disturbance in early childhood.

STUDY OBJECTIVE: Temperament was explored as a factor in both night-waking and bedsharing in preschool-aged children. DESIGN: Bedsharers and solitary sleepers were categorized based on the frequency of current bedsharing. MANOVA was used to examine associations among temperament and sleep measures. SETTING: Two preschools affiliated with a rural university in the Northeast United States. Participants. 67 children between 2.4-5.6 years of age from two University-affiliated preschools were studied. INTERVENTION: Child temperament was rated by parents and teachers using the Carey Temperament Scale and compared to night-waking, current sleep habits, and the circumstances in which bedsharing occurred MEASUREMENTS AND RESULTS: Parents and preschool teachers completed the Carey Temperament Scale for 3-7 year olds. Parents also scored the Sleep Habits Inventory and the Sleeping Arrangements Inventory, which provided a current and retrospective history of the child's sleep location and sleep patterns. Parents' ratings showed that bedsharers have less regular bedtimes; difficulty with sleep onset; more night-waking; and seek out the parents following awakening during the night. Temperamentally, bedsharers were found to be more intense and exhibit less adaptability and rhythmicity. However, teachers' temperament ratings did not predict bedsharing and were not concordant with parental ratings. CONCLUSIONS: These findings suggest that bedsharing at preschool age is a complex phenomenon related to parents' ratings of child temperament, sleep habits, and disturbances such as night waking. Implications for the clinical assessment of sleep disorders are discussed.

Child, Preschool↗
PubMed2005

Comparative genomics of two closely related unicellular thermo-acidophilic red algae, Galdieria sulphuraria and Cyanidioschyzon merolae, reveals the molecular basis of the metabolic flexibility of Galdieria sulphuraria and significant differences in carbohydrate metabolism of both algae.

Unicellular algae serve as models for the study and discovery of metabolic pathways, for the functional dissection of cell biological processes such as organellar division and cell motility, and for the identification of novel genes and gene functions. The recent completion of several algal genome sequences and expressed sequence tag collections and the establishment of nuclear and organellar transformation methods has opened the way for functional genomics approaches using algal model systems. The thermo-acidophilic unicellular red alga Galdieria sulphuraria represents a particularly interesting species for a genomics approach owing to its extraordinary metabolic versatility such as heterotrophic and mixotrophic growth on more than 50 different carbon sources and its adaptation to hot acidic environments. However, the ab initio prediction of genes required for unknown metabolic pathways from genome sequences is not trivial. A compelling strategy for gene identification is the comparison of similarly sized genomes of related organisms with different physiologies. Using this approach, candidate genes were identified that are critical to the metabolic versatility of Galdieria. Expressed sequence tags and high-throughput genomic sequence reads covering >70% of the G. sulphuraria genome were compared to the genome of the unicellular, obligate photoautotrophic red alga Cyanidioschyzon merolae. More than 30% of the Galdieria sequences did not relate to any of the Cyanidioschyzon genes. A closer inspection of these sequences revealed a large number of membrane transporters and enzymes of carbohydrate metabolism that are unique to Galdieria. Based on these data, it is proposed that genes involved in the uptake of reduced carbon compounds and enzymes involved in their metabolism are crucial to the metabolic flexibility of G. sulphuraria.

Algal Proteins↗
PubMed1993

Self-identity and specific vulnerability to depressed mood.

Four studies were conducted to test the hypothesis that experiencing a life event that disrupts the pursuit of self-defining activities would be associated with depressed mood. Across all four studies, a strong and exclusive identification with the athlete role was related to subjects' affective response to both hypothetical and actual athletic injuries. The results highlight the importance of assessing the match between specific cognitive diatheses and specific life events in predicting depressive reactions.

Adaptation, Psychological↗
PubMed2000

Interaction of modeling and experimental approaches to understanding renal salt and water balance.

Understanding of renal function has profited greatly from quantitative and modeling approaches throughout this century. One of the most salient examples is the concentration and dilution of the urine--a fundamental characteristic of the mammalian kidney. Only in the last three decades have the necessary components of this and other renal mechanisms been confirmed at the molecular level, but there have also been surprises. For example, the high water permeability of the proximal tubule has been shown to be imparted by the water channel, aquaporin AQP1; however, genetic knockout of this water channel is at least partially compensated by intrarenal feedback mechanisms. Also, the critical role played by the fine regulation of Na+ reabsorption in the collecting duct for the maintenance of normal blood pressure presents challenges to our understanding of the integrated interaction among systems. As a first step in placing the kidney in the physiome paradigm, we need to integrate our currently restricted mathematical models, to develop accessible databases of critical parameter values together with indices of their degrees of reliability and variability, and to describe regulatory mechanisms and their interactions from the molecular to the interorgan level. However, even greater will be the challenge to anticipate, and hopefully predict, the subtle ways in which the organism typically adapts to aberrations in these normal functional parameters, but sometimes does not.

Animals↗
PubMed1983

Electrophoresis: mathematical modeling and computer simulation.

A mathematical model of electrophoretic separation processes has been developed and adapted for computer simulations. The model is used to predict the characteristic behavior of a variety of electrophoretic techniques from a knowledge of chemical equilibria and physical transport phenomena. The model provides a unifying basis for a rational classification of all electrophoretic processes.

Computers↗
PubMed1983

Within-breath PCO2 levels in the airways and at the pulmonary stretch receptor sites.

The discharge frequency of pulmonary stretch receptors (PSRs) shows an inverse responsiveness to the CO2 partial pressure (PCO2), which is limited to an extremely hypocapnic range. During inspiration extremely hypocapnic PCO2 levels are obtained in a large part of the respiratory tract due to the diffusion limited gas mixing. The question remains whether PSRs in combination with these low levels of PCO2 are involved in the regulation of breathing. As a necessary first step to be able to answer this question, this paper is devoted to the calculation of the within-breath PCO2 transients in the respiratory tract and the corresponding PCO2 oscillations in the superficial airway tissue. For PSRs located in the smooth muscles of large bronchi, the calculations predict a time delay of a few seconds to adapt their discharge frequency to a change in PCO2 in the airway lumen. The result is in good agreement with the observed time delay reported in the literature. For the PSRs located in the acini the calculated time constant of their discharge response to PCO2 variations in the lumen is much smaller than 250 ms. This implies a within-breath response to the oscillating luminal PCO2. Further, the calculations show that a CO2 diffusion front is established within the acini during early inspiration. This diffusion front penetrates further and further into the acini with increasing work load due to the concomitant increase in inspiratory flow. As a consequence, the discharge frequency vs. volume response curve of PSRs, especially those located in distal airways, may be modified by a flow-induced PCO2-related contribution.(ABSTRACT TRUNCATED AT 250 WORDS)

Arteries↗
PubMed2000

Intrinsic dynamics in neuronal networks. I. Theory.

Many networks in the mammalian nervous system remain active in the absence of stimuli. This activity falls into two main patterns: steady firing at low rates and rhythmic bursting. How are these firing patterns generated? Specifically, how do dynamic interactions between excitatory and inhibitory neurons produce these firing patterns, and how do networks switch from one firing pattern to the other? We investigated these questions theoretically by examining the intrinsic dynamics of large networks of neurons. Using both a semianalytic model based on mean firing rate dynamics and simulations with large neuronal networks, we found that the dynamics, and thus the firing patterns, are controlled largely by one parameter, the fraction of endogenously active cells. When no endogenously active cells are present, networks are either silent or fire at a high rate; as the number of endogenously active cells increases, there is a transition to bursting; and, with a further increase, there is a second transition to steady firing at a low rate. A secondary role is played by network connectivity, which determines whether activity occurs at a constant mean firing rate or oscillates around that mean. These conclusions require only conventional assumptions: excitatory input to a neuron increases its firing rate, inhibitory input decreases it, and neurons exhibit spike-frequency adaptation. These conclusions also lead to two experimentally testable predictions: 1) isolated networks that fire at low rates must contain endogenously active cells and 2) a reduction in the fraction of endogenously active cells in such networks must lead to bursting.

Action Potentials↗
PubMed2005

Predictors of treatment response for suicidal youth referred for emergency psychiatric hospitalization.

This study evaluated factors that predicted poor treatment response for 70 suicidal youth (ages 10 to 17 years; 67% African American) who received either multisystemic therapy (MST) or inpatient psychiatric hospitalization. Following treatment, suicidal youth were classified as either treatment responders or nonresponders based on caregiver or youth report of attempted suicide. Overall, female gender, depressive affect, parental control, caregiver psychiatric distress, and caregiver history of psychiatric hospitalization were associated with suicide attempts. However, controlling for other variables, only depressive affect and parental control predicted treatment nonresponse. These results suggest the need to adapt existing treatments for suicidal youth to better address problems relating to youth depression.

Adolescent↗
PubMed2000

The transtheoretical stages of change as a predictor of premature termination, attendance and alliance in psychotherapy.

OBJECTIVE: The Transtheoretical Model proposes that clients' stage of change will predict their engagement in therapy. This study tested the hypotheses that clients with high Precontemplation scores would prematurely terminate from therapy and that clients with high Action scores would attend a greater number of sessions and establish a more positive therapeutic alliance. DESIGN: Using a within-subjects design, baseline measures of stage of change were used to predict the number of sessions attended, premature drop-out from therapy, and the therapeutic alliance after sessions one and three. METHODS: Sixty clients completed the Stages of Change Scales and the Brief Symptom Inventory prior to therapy. The therapeutic alliance was assessed after the first and third therapy session using the Agnew Relationship Measure. RESULTS: The specific hypotheses were not supported. Premature termination from therapy was predicted by high level of initial symptom severity and low Contemplation scores. Positive therapeutic alliance at session one and session three was predicted by high Contemplation at baseline. CONCLUSIONS: These results suggest that the Transtheoretical Model, which was developed in the context of interventions for behavioural change, may not be directly generalizable to outpatient psychotherapy populations. However, Contemplation did predict premature termination and engagement. This implies that with adaptation the model may be a useful adjunct to psychotherapy assessment.

Adult↗
PubMed2005

The science of cycling: physiology and training - part 1.

The aim of this review is to provide greater insight and understanding regarding the scientific nature of cycling. Research findings are presented in a practical manner for their direct application to cycling. The two parts of this review provide information that is useful to athletes, coaches and exercise scientists in the prescription of training regimens, adoption of exercise protocols and creation of research designs. Here for the first time, we present rationale to dispute prevailing myths linked to erroneous concepts and terminology surrounding the sport of cycling. In some studies, a review of the cycling literature revealed incomplete characterisation of athletic performance, lack of appropriate controls and small subject numbers, thereby complicating the understanding of the cycling research. Moreover, a mixture of cycling testing equipment coupled with a multitude of exercise protocols stresses the reliability and validity of the findings. Our scrutiny of the literature revealed key cycling performance-determining variables and their training-induced metabolic responses. The review of training strategies provides guidelines that will assist in the design of aerobic and anaerobic training protocols. Paradoxically, while maximal oxygen uptake (V-O(2max)) is generally not considered a valid indicator of cycling performance when it is coupled with other markers of exercise performance (e.g. blood lactate, power output, metabolic thresholds and efficiency/economy), it is found to gain predictive credibility. The positive facets of lactate metabolism dispel the 'lactic acid myth'. Lactate is shown to lower hydrogen ion concentrations rather than raise them, thereby retarding acidosis. Every aspect of lactate production is shown to be advantageous to cycling performance. To minimise the effects of muscle fatigue, the efficacy of employing a combination of different high cycling cadences is evident. The subconscious fatigue avoidance mechanism 'teleoanticipation' system serves to set the tolerable upper limits of competitive effort in order to assure the athlete completion of the physical challenge. Physiological markers found to be predictive of cycling performance include: (i) power output at the lactate threshold (LT2); (ii) peak power output (W(peak)) indicating a power/weight ratio of > or =5.5 W/kg; (iii) the percentage of type I fibres in the vastus lateralis; (iv) maximal lactate steady-state, representing the highest exercise intensity at which blood lactate concentration remains stable; (v) W(peak) at LT2; and (vi) W(peak) during a maximal cycling test. Furthermore, the unique breathing pattern, characterised by a lack of tachypnoeic shift, found in professional cyclists may enhance the efficiency and metabolic cost of breathing. The training impulse is useful to characterise exercise intensity and load during training and competition. It serves to enable the cyclist or coach to evaluate the effects of training strategies and may well serve to predict the cyclist's performance. Findings indicate that peripheral adaptations in working muscles play a more important role for enhanced submaximal cycling capacity than central adaptations. Clearly, relatively brief but intense sprint training can enhance both glycolytic and oxidative enzyme activity, maximum short-term power output and V-O(2max). To that end, it is suggested to replace approximately 15% of normal training with one of the interval exercise protocols. Tapering, through reduction in duration of training sessions or the frequency of sessions per week while maintaining intensity, is extremely effective for improvement of cycling time-trial performance. Overuse and over-training disabilities common to the competitive cyclist, if untreated, can lead to delayed recovery.

Acidosis, Lactic↗
PubMedDate not supplied

Using DNA microarrays to study host-microbe interactions.

Complete genomic sequences of microbial pathogens and hosts offer sophisticated new strategies for studying host-pathogen interactions. DNA microarrays exploit primary sequence data to measure transcript levels and detect sequence polymorphisms, for every gene, simultaneously. The design and construction of a DNA microarray for any given microbial genome are straightforward. By monitoring microbial gene expression, one can predict the functions of uncharacterized genes, probe the physiologic adaptations made under various environmental conditions, identify virulence-associated genes, and test the effects of drugs. Similarly, by using host gene microarrays, one can explore host response at the level of gene expression and provide a molecular description of the events that follow infection. Host profiling might also identify gene expression signatures unique for each pathogen, thus providing a novel tool for diagnosis, prognosis, and clinical management of infectious disease.

Algorithms↗
PubMedDate not supplied

Focus on health promotion: self-efficacy in oncology nursing research and practice.

PURPOSE/OBJECTIVES: To discuss self-efficacy in oncology nursing research and practice in promoting health for people with cancer. DATA SOURCES: Published articles, abstracts, and books; consultations. DATA SYNTHESIS: Self-efficacy has much merit as a concept to guide oncology nursing research and practice related to health promotion. It has strong predictive capability in nononcology populations for determining the likelihood of individuals engaging in health-promotion behaviors. In oncology, it has been an effective determinant to predict disease prevention and early-detection behaviors and adaptation to cancer. CONCLUSIONS: Self-efficacy provides prescriptive specificity to guide clinical interventions to promote health in people with cancer. IMPLICATIONS FOR NURSING PRACTICE: Exercise for people with cancer recently has been emphasized, and specific examples of cancer nursing research and practice using self-efficacy to increase participation in this health-promotion behavior have been suggested. Research that tests this concept further as a basis for health promotion in people with cancer is needed.

Clinical Nursing Research↗