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PubMed2004

Dynamics of production of sexual forms in aphids: theoretical and experimental evidence for adaptive "coin-flipping" plasticity.

The best strategy for an organism to deal with unpredictable environmental conditions is a stochastic one, but it is not easy to distinguish it from nonadaptive randomness in phenotype production, and its convincing demonstrations are lacking. Here we describe a new method for detection of adaptive stochastic polyphenism and apply it to the following problem. In fall, each female of the bird cherry-oat aphid, Rhopalosiphum padi, faces a decision either to produce sexuals, which mate and lay cold-tolerant eggs, or to continue production of cold-sensitive parthenogenetic females, which potentially yields a higher population growth rate but is risky because a cold winter can kill all of her descendants. Using a simulation model, we show that global investment in sexual reproduction should be proportional to winter severity and that variance in the peak date of production of sexual individuals should depend on climate predictability. Both predictions are validated against standardized trap data on aphid flight accompanied by meteorological data, and the predictions support adaptive phenotypic plasticity.

Adaptation, Physiological↗
PubMed1996

Preliminary testing of a proposition from the Roy Adaptation Model.

OBJECTIVE: To test a framework based on a proposition of the Roy Adaptation Model predicting the relationships of severity of illness, perceived control over visitation (PCV), hardiness, state anxiety, and length of stay in an intensive care unit (ICU). DESIGN: Descriptive-correlational. POPULATION, SAMPLE, SETTING: Convenience sample was 60 general medical-surgical ICU patients admitted to one regional medical center in the Southeastern U.S.A. Patients completed data collection instruments after a minimum of 20 hours in the ICU during January-March 1994. METHODS: Instruments included the PCV Scale, the State Anxiety Inventory, the Health Related Hardiness Scale, and the Acute Physiologic and Chronic Health Evaluation II. Model testing and path analysis were done. FINDINGS: The study variables explained 18% of the variance in length of stay in the ICU, with anxiety and hardiness being the major contributing variables. The path between hardiness and PCV was the only path in the model supported by the data. CONCLUSIONS: The proposed model had inadequate support in this preliminary testing. However, interventions that increase a patient's feelings of control and hardiness could decrease length of stay in ICU's.

APACHE↗
PubMed2005

Pretreatment serum hemoglobin level as a predictive factor of response to neoadjuvant chemotherapy in patients with locally advanced squamous cervical carcinoma: a preliminary report.

OBJECTIVE: The aim of this study was to evaluate the predictive value of pretreatment serum hemoglobin level (Hb) together with a series of clinical and pathological variables available before neoadjuvant chemotherapy in locally advanced squamous cervical cancer. METHODS: The influence on response to neoadjuvant chemotherapy of a series of pretreatment clinico-pathological features: hemoglobin level at diagnosis, age, parity, menopausal status, body mass index, clinical stage, tumor diameter, and nuclear grading were analyzed on 73 patients with locally advanced cervical cancer treated with platinum-based neoadjuvant chemotherapy followed by radical surgery. The relationships between pretreatment variables and response to chemotherapy were assessed in univariate and multivariate settings. A univariate and multivariate logistic regression model was adapted to predict an "optimal" response (pathological complete response or more than 50% reduction in tumoral diameter) or "sub-optimal" response (<50% reduction in tumoral diameter). RESULTS: Seventy-three patients-clinical stage: Ib2: 29 (39.7%) IIa: 22 (30.1%) IIb: 22 (30.1%)-received 3 cycles of platinum-based neoadjuvant chemotherapy followed by type III radical hysterectomy. A complete response to neoadjuvant chemotherapy was significantly associated with higher level of pretreatment hemoglobin (mean 14.0 mg/dl) compared to patients with > or =50% response (12.7 mg/dl) or <50% (11.9 mg/dl) (P = 0.002). At multivariate analysis, Hb level was found to be the most powerful and significantly related factor to response to neoadjuvant chemotherapy. A hemoglobin threshold of 12 mg/dl was able to distinguish between patients-with > or =12 mg/dl-at higher probability to respond to neoadjuvant chemotherapy from the ones at lower probability (hemoglobin level under 12 mg/dl). Patients with a complete response to chemotherapy had a 100% survival compared to 93.1% and 53.8% for patients with responses > or =50% and <50% respectively (P = 0.0001). Patients with a pretreatment hemoglobin level of > or =12 mg/dl showed a survival of 87% compared to 63% for patients with a lower hemoglobin level (P = 0.008). CONCLUSIONS: Pretreatment Hb level showed a prognostic and independent predictive value for response to neoadjuvant chemotherapy in locally advanced cervical cancer. In our preliminary report, performed on a limited sample, a threshold of 12 mg/dl seems to be helpful to distinguish between "optimal" and "non-optimal" response.

Analysis of Variance↗
PubMedDate not supplied

[Effect of family environment on adaptation to the hemodialysis program in patients with chronic renal insufficiency].

In our study we have analyzed the influence of family environment on adjustment of renal patients to the HD as well as on the attitude towards kidney transplantation. The study included 57 patients (34 M, 23 F), mean age 52.3 years, and they had been on dialysis for an average of 34.5 months. We obtained information about adaptation and behavior in the care unit, and attitude and motivation towards renal transplantation. Biochemical variables were used to register disruption of medical compliance or dietetic transgression (K, PRC, BUN, weight gain, etc.). The patient's family climate was assessed through use of the Family Environment Scale (FES, Moos and Moos, 1981). The results showed that patients with aggressiveness and noncompliance during HD sessions tended to have high family conflict in family members. The most positive attitudes towards renal transplantation were found in the patients that came from families with the greatest degree of cohesion and expressiveness. In summary, family social climate is a variable influencing outcome of these patients. Its routine assessment would permit the prediction of adaptation to the therapeutic program as much as better efficacy of HD treatment.

Adaptation, Psychological↗
PubMed2005

The evolutionary genetics of egg size plasticity in a butterfly.

Abstract The evolution of phenotypic plasticity requires that it is adaptive, genetically determined, and exhibits sufficient genetic variation. For the tropical butterfly Bicyclus anynana there is evidence that temperature-mediated plasticity in egg size is an adaptation to predictable seasonal change. Here we set out to investigate heritability in egg size and genetic variation in the plastic response to temperature in this species, using a half-sib breeding design. Egg size of individual females was first measured at a high temperature 4 days after eclosion. Females were then transferred to a low temperature and egg size was measured after acclimation periods of 6 and 12 days respectively. Overall, additive genetic variance explained only 3-11% of the total phenotypic variance, whereas maternal effects were more pronounced. Genotype-environment interactions and cross-environmental correlations of less than unity suggest that there is potential for short-term evolutionary change. Our findings strengthen the support for the adaptive nature of temperature-mediated plasticity in egg size.

Adaptation, Physiological↗
PubMed1997

Acclimation to low irradiance in Picea abies: influences of past and present light climate on foliage structure and function.

Leaf retention time increases with decreasing irradiance, providing an effective way of amortizing the costs of foliage construction over time. To elucidate the physiological mechanisms underlying this dependence, I studied needle life span, morphology, and concentrations of carbon, nitrogen and nonstructural carbohydrates along a gradient of relative irradiance in understory trees of Picea abies (L.) Karst. Maximum needle life span was greater in shaded trees than in sun-exposed trees. However, irrespective of irradiance, needles with maximum longevity were situated in the middle rather than the bottom of the canopy, suggesting that needle life span is determined by the irradiance to which needles are exposed during their primary growth. Morphology and chemistry of current-year needles were adapted to prevailing light conditions. Current-year needles exposed to high irradiances had greater packing of foliar biomass per unit area than shaded needles, whereas shaded needles maximized foliar area to capture more light. Nitrogen concentrations were higher in shaded needles than in sun-exposed needles. This nitrogen distribution pattern was related to the high nitrogen cost of light interception and was assumed to improve light absorptance per needle mass of shaded needles. In contrast, in both 1- and 2-year-old needles, morphology was independent of prevailing light conditions; however, needle nitrogen concentrations were adjusted toward more effective light interception in 2-year-old foliage but not in 1-year-old foliage, indicating that acclimation of sun-adapted needles to shading takes more than one year. At the same time, needle aging was accompanied by accumulation of nonstructural carbohydrates (NSC), and increasing concentrations of needle carbon, suggesting a shift in the balance between photosynthesis and photosynthate export. The accumulation of NSC and carbon resulted in a dilution of the concentrations of other needle chemicals and explained the decline in needle nitrogen concentrations with increasing age. Thus, although morphological inadequacy to low light availabilities may partly be compensated for by modifications in needle chemistry, age-related changes in needle stoichiometric composition progressively lessen the potential for acclimation to low irradiance. A conceptual model, advanced to explain how environmental factors and age-related changes in the activities of needle xylem and phloem transport affect needle longevity, predicted that adaptation of needle morphology to irradiance during the primary growth period largely determines the fate of needles during subsequent tree growth and development.

Journal Article↗
PubMed2003

An evolutionary advantage of haploidy in large yeast populations.

Although seed plants and multicellular animals are predominantly diploid, the prominence of diploidy varies greatly among eukaryote life cycles, and no general evolutionary advantage of diploidy has been demonstrated. By doubling the copy number of each gene, diploidy may increase the rate at which adaptive mutations are produced. However, models suggest that this does not necessarily accelerate adaptation by diploid populations. We tested model predictions regarding rates of adaptation using asexual yeast populations. Adaptive mutations were on average partially recessive. As predicted, diploidy slowed adaptation by large populations but not by small populations.

Adaptation, Physiological↗
PubMedDate not supplied

The [3H]dofetilide binding assay is a predictive screening tool for hERG blockade and proarrhythmia: Comparison of intact cell and membrane preparations and effects of altering [K+]o.

INTRODUCTION: The human ether-a-go-go-related gene (hERG) encodes a potassium channel responsible for the cardiac delayed rectifier current (IKr) involved in ventricular repolarization. Drugs that block hERG have been associated with QT interval prolongation and serious, sometimes fatal, cardiac arrhythmias (including torsade de pointes). While displacement of [3H]dofetilide, a potent methanesulfonanilide hERG blocker, from cells heterologously expressing hERG has been suggested as a screening assay, questions have been raised about its predictive value. METHODS: To validate the utility of this assay as a screening tool, we performed a series of saturation and competition binding studies using [3H]dofetilide as ligand and either intact cells or membrane preparations from HEK 293 cells stably transfected with hERG K+ channels. The object of these experiments was to (1) compare binding Ki values for 22 hERG blockers using intact cells or membrane homogenates to determine whether maintaining cell integrity enhanced assay reliability; (2) evaluate the ability of different K+ concentrations (2, 5, 10, 20, and 60 mM) to modulate hERG binding; and (3) to establish the predictive value of the assay by comparing Ki values from binding studies at 5 and 60 mM [K+]o to functional IC50 values for hERG current block using 56 structurally diverse drugs. RESULTS: We found (a) comparable Ki values in the intact cell and isolated membrane binding assays, although there were some differences in rank order; (b) increasing [K+]o lowered the Kd and increased the Bmax for [3H]dofetilide, particularly in the membrane assay; and (c) good correlation between binding Ki values and functional IC50 values for hERG current block. DISCUSSION: In conclusion, increasing K+ concentrations results in an increase in both [3H]dofetilide affinity for hERG and available binding sites, particularly when using membrane homogenates. There are no meaningful differences between Ki values when comparing intact cell versus membrane assay, neither are there meaningful trends with increasing [K+]o within assays. There is good correlation between binding Ki values and functional (whole-cell patch clamp) IC50 values at both 5 and 60 mM K+ concentrations (R2 values of .824 and .863, respectively). The simplicity, predictability, and adaptability to high-throughput platforms make the [3H]dofetilide membrane binding assay a useful tool for screening and ranking compounds for their potential to block the hERG K+ channel.

Anti-Arrhythmia Agents↗
PubMed1993

The role of social comparisons processes in the psychological adaptation of elderly adults.

Social comparison processes were investigated as mechanisms by which elderly women maintain or enhance their psychological well-being in the face of health-related threats or loss. In Study 1, a measure of social comparisons was tested, and a preliminary model of the effects of health and social comparisons on depression was examined (N = 42). In Study 2, a separate sample of elderly women (N = 243) completed self-report measures concerning physical health, upward and downward social comparison processes, and positive and negative aspects of psychological adaptation. As predicted, worse physical health status was linked to more frequent social comparisons; however, more positive social comparisons were related to better mental health outcomes, even for women in poor health. In fact, the effects of social comparisons were strongest for women in the poorest health, resulting in psychological outcomes similar to women in good health. Thus, social comparisons appear to play a significant role in psychological well-being in old age. The findings also point to the importance of distinguishing between frequency and consequences of social comparison processes.

Activities of Daily Living↗
PubMed2002

The Schedule for Nonadaptive and Adaptive Personality (SNAP): temporal stability and predictive validity of the diagnostic scales.

The authors investigated the test-retest reliability and predictive validity of the diagnostic scales from the Schedule for Nonadaptive and Adaptive Personality (SNAP). Participants were identified from a sample of 240 undergraduates who completed the SNAP and the Social Adjustment Scale (SAS-SR) at Time 1. The authors selected 50 people who met criteria for a personality disorder (PD) based on the SNAP and 50 who did not qualify for a diagnosis. Eighty-three of these people completed the SNAP and the SAS-SR for a second time approximately 9 months after initial screening. SNAP PD scales were relatively stable over time. Test-retest correlation coefficients ranged from .58 to .81. Scores on diagnostic scales for paranoid, schizoid, and schizotypal PD were inversely related to self-reported levels of adjustment for social roles concerned with work as a student, leisure activities, and relationships with family. The results provide some evidence for the validity of the SNAP

Adaptation, Psychological↗
PubMed2007

Reductive evolution and niche adaptation inferred from the genome of Mycobacterium ulcerans, the causative agent of Buruli ulcer.

Mycobacterium ulcerans is found in aquatic ecosystems and causes Buruli ulcer in humans, a neglected but devastating necrotic disease of subcutaneous tissue that is rampant throughout West and Central Africa. Here, we report the complete 5.8-Mb genome sequence of M. ulcerans and show that it comprises two circular replicons, a chromosome of 5632 kb and a virulence plasmid of 174 kb. The plasmid is required for production of the polyketide toxin mycolactone, which provokes necrosis. Comparisons with the recently completed 6.6-Mb genome of Mycobacterium marinum revealed >98% nucleotide sequence identity and genome-wide synteny. However, as well as the plasmid, M. ulcerans has accumulated 213 copies of the insertion sequence IS2404, 91 copies of IS2606, 771 pseudogenes, two bacteriophages, and multiple DNA deletions and rearrangements. These data indicate that M. ulcerans has recently evolved via lateral gene transfer and reductive evolution from the generalist, more rapid-growing environmental species M. marinum to become a niche-adapted specialist. Predictions based on genome inspection for the production of modified mycobacterial virulence factors, such as the highly abundant phthiodiolone lipids, were confirmed by structural analyses. Similarly, 11 protein-coding sequences identified as M. ulcerans-specific by comparative genomics were verified as such by PCR screening a diverse collection of 33 strains of M. ulcerans and M. marinum. This work offers significant insight into the biology and evolution of mycobacterial pathogens and is an important component of international efforts to counter Buruli ulcer.

Adaptation, Physiological↗
PubMed2026

GiantHost: a domain-adaptive and uncertainty-aware framework for giant virus host prediction.

MOTIVATION: Nucleocytoplasmic large DNA viruses (NCLDVs) play crucial roles in global ecosystems. Although metagenomics has vastly accelerated the discovery of novel NCLDVs, predicting their hosts from fragmented contigs remains a critical bottleneck, with no dedicated end-to-end computational tools currently available. Addressing this gap requires overcoming three fundamental challenges: the extreme scarcity of labeled reference genomes, the severe domain shift between laboratory isolates and diverse environmental metagenomes, and the inability of traditional deterministic models to quantify prediction uncertainty-a crucial requirement for reliable ecological profiling where novel, divergent viruses are prevalent. RESULTS: We present GiantHost, the first NCLDV host prediction tool with domain adaptation and uncertainlty awareness. GiantHost employs a dual-tower neural network to integrate dense genome traits and sparse GVOG profiles, allowing better integration of heterogeneous features. To overcome label scarcity and domain shift, we leverage 1400 environmental viral genomes (GVMAGs) via semi-supervised multi-task learning and Domain Adversarial Neural Networks (DANN), effectively bridging the distributional gap between RefSeq and environmental data. Additionally, GiantHost incorporates Conformal Prediction (CP) to output statistically guaranteed prediction sets rather than overconfident single labels. Evaluated under rigorous genome-level cross-validation, GiantHost demonstrates robust predictive power. Applied to the Tara Ocean dataset, GiantHost successfully captured the vertical stratification of NCLDV hosts-revealing a depth-dependent decline of phytoplankton-infecting viruses and a relative enrichment of Amoebozoa-infecting viruses in the mesopelagic zone. AVAILABILITY: The source code of GiantHost is available via: https://github.com/FuchuanQu/GiantHost.

Giant Viruses↗
PubMed2002

Escherichia coli K-12 undergoes adaptive evolution to achieve in silico predicted optimal growth.

Annotated genome sequences can be used to reconstruct whole-cell metabolic networks. These metabolic networks can be modelled and analysed (computed) to study complex biological functions. In particular, constraints-based in silico models have been used to calculate optimal growth rates on common carbon substrates, and the results were found to be consistent with experimental data under many but not all conditions. Optimal biological functions are acquired through an evolutionary process. Thus, incorrect predictions of in silico models based on optimal performance criteria may be due to incomplete adaptive evolution under the conditions examined. Escherichia coli K-12 MG1655 grows sub-optimally on glycerol as the sole carbon source. Here we show that when placed under growth selection pressure, the growth rate of E. coli on glycerol reproducibly evolved over 40 days, or about 700 generations, from a sub-optimal value to the optimal growth rate predicted from a whole-cell in silico model. These results open the possibility of using adaptive evolution of entire metabolic networks to realize metabolic states that have been determined a priori based on in silico analysis.

Acetic Acid↗
PubMed2005

Validation and adaptation of a nomogram for predicting the survival of patients with extremity soft tissue sarcoma using a three-grade system.

BACKGROUND: A nomogram for predicting long term tumor-specific death in patients with soft tissue sarcoma (STS) was developed at the Memorial Sloan-Kettering Cancer Center (MSKCC). METHODS: To assess the performance of the MSKCC nomogram, 642 consecutive patients with extremity STS who underwent surgery over a 20-year span at a single referral center were analyzed. Nomogram predictions were based on tumor size, depth, site, patient age, histologic subtype, and grade. The latter, at variance with the system in use at the MSKCC, was classified as Grade 1-3 according to the French Federation of Cancer Centers Sarcoma Group (FNCLCC) system. The statistical approach used for nomogram performance assessment was that of "validation by calibration" proposed by Van Houwelingen. RESULTS: Graphic comparison of observed and predicted sarcoma-specific survival curves showed that predictions by the nomogram were quite accurate, within 10% of actual survival for all prognostic strata. Statistical analysis showed that such predictions could be improved by employing approximately 25% shrinkage to achieve good calibration. The contribution of histologic grade was highly significant in both univariate analysis (P < 0.001) and multivariate analysis (P < 0.001), and a survival trend across the 3 grade categories was observed. Based on those findings, a nomogram that included the FNCLCC histologic grade classification was produced. CONCLUSIONS: Results of the current study confirmed that the MSKCC nomogram is a valuable tool for individual prognostic assessment. A nomogram that included the FNCLCC histologic grade classification was proposed and was validated internally.

Adolescent↗
PubMed1983

Pharmacokinetic model for diazepam and its major metabolite desmethyldiazepam following diazepam administration.

A five-compartment open model was used to simulate the blood concentration profiles of diazepam and its metabolite, desmethyldiazepam, following single- and multiple-dose administrations of diazepam. The parameter estimates for diazepam were previously reported literature values. The parameters estimates for the metabolite were calculated from literature values of blood concentrations of desmethyldiazepam following the administration of clorazepate. The five-compartment open model suggests that approximately 50% of the administered diazepam is biotransformed to desmethyldiazepam, and that the elimination profile of the metabolite is not altered by the presence of the drug. The model may also be readily adapted to predict the concentrations of diazepam and desmethyldiazepam in cerebrospinal fluid following the administration of diazepam by simply correcting the blood or plasma concentrations of the drug and metabolite for the degree of plasma protein binding.

Adult↗
PubMed1981

Comparison of two modes of stress measurement: daily hassles and uplifts versus major life events.

The standard life events methodology for the prediction of psychological symptoms was compared with one focusing on relatively minor events, namely, the hassles and uplifts of everyday life. Hassles and Uplifts Scales were constructed and administered once a month for 10 consecutive months to a community sample of middle-aged adults. It was found that the Hassles Scale was a better predictor of concurrent and subsequent psychological symptoms than were the life events scores, and that the scale shared most of the variance in symptoms accounted for by life events. When the effects of life events scores were removed, hassles and symptoms remained significantly correlated. Uplifts were positively related to symptoms for women but not for men. Hassles and uplifts were also shown to be related, although only modestly so, to positive and negative affect, thus providing discriminate validation for hassles and uplifts in comparison to measures of emotion. It was concluded that the assessment of daily hassles and uplifts may be a better approach to the prediction of adaptational outcomes than the usual life events approach.

Adaptation, Psychological↗
PubMed1979

Transportation, stress, and community psychology.

Conditions of transportation were investigated as sources of psychological stress as they affect the physiology, task performance, and mood of commuters. Participants in the study were 100 employees of industrial firms. Traffic congestion was construed as a behavioral constraint in terms of the concept of impedance which is defined by the parameters of distance and time. It was expected that the effects of impedance would be mediated by personality factors, such as locus of control. Multivariate tests of the internal validity of the impedance factor were significant. However, significant main effects for impedance were obtained only for mood and residential adaptation. The predicted interactions of impedance with locus of control were obtained across task performance indices. In multiple regression analyses, the distance and speed of the commute to work were found to account for significant proportions of variation in blood pressure, while several indices of personal control had significant regression effects on the task measures. The implications of the results for research in community psychology are discussed.

Adult↗