Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “predictability of adaptation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 919 records · Page 51Linked to original sources
PubMed2002

Regression of left ventricular hypertrophy: hoping for a longer life.

Left ventricular hypertrophy (LVH) is more than just an adaptive response to hypertension. It predicts a poor prognosis independently of the blood pressure (BP) level. There is increasing evidence from studies such as Heart Outcomes Prevention Evaluation (HOPE) and Losartan Intervention For Endpoint reduction in hypertension (LIFE) that LVH should be a target for treatment, above and beyond BP control. It is likely that drugs blocking the renin-angiotensin-aldosterone system cause greater regression of LVH than other agents and this is probably the mechanism that explains the superiority of losartan over atenolol in the LIFE study. In order to achieve the stringent BP goals suggested by modern guidelines, most patients will require multiple antihypertensive agents and the clinical choices relate more often to which combinations of drugs are most appropriate, rather than which single drug is the best. Tight BP control should be the first priority and this is likely to lead to regression of LVH.

Drug Therapy, Combination↗
PubMed2000

Lossless compression of emission tomography images.

An adaptive lossless compression method using predictive coding with the Rice codes is proposed for low resolution three-dimensional biomedical images. The method is evaluated with the brain positron emission tomography (PET) images. The results are considerably better than with static arithmetic coding.

Algorithms↗
PubMed2001

Psychosocial issues in space: future challenges.

As the duration of space flights increases and crews become more heterogeneous, psychosocial factors are likely to play an increasingly important role in determining mission success. The operations of the International Space Station and planning of interplanetary missions represent important future challenges for how to select, train and monitor crews. So far, empirical evidence about psychological factors in space is based on simulations and personnel in analog environments (i.e. polar expeditions, submarines). It is apparent that attempts to transfer from these environments to space requires a thorough analysis of the human behavior specific to the fields. Recommendations for research include the effects of multi-nationality on crew interaction, development of tension within crews and between Mission Control, and prediction of critical phases in adaptation over time. Selection of interpersonally compatible crews, pre-mission team training and implementation of tools for self-monitoring of psychological parameters ensure that changes in mission requirements maximize crew performance.

Adaptation, Psychological↗
PubMed2005

[Prognostic value of stromal immunolabelling by MMP-2, MT1-MMP and TIMP-2 in clinically localized prostate cancer].

INTRODUCTION: Metalloproteinases (MMPs) promote cell migration and tumour invasion by degradation of the extracellular matrix. Activators and inhibitors (such as membrane type 1-matrix metalloproteinase or MT1-MMP and tissue inhibitor metalloproteinase 2 or TIMP-2) regulate metalloproteinase activity. The objective of this study was to determine the prognostic value of stromal immunolabelling with MMP-2, MT1-MMP and TIMP-2 in clinically localized prostate cancer. MATERIAL AND METHODS: The immunohistochemical study was performed on 30 radical prostatectomy specimens. The results were compared to preoperative PSA, Gleason score, pT stage and biochemical recurrence with a minimum follow-up of 5 years. RESULTS: Stromal immunolabelling with MMP-2 is correlated with stage pT3 (p=0.0022, OR=17.5). No correlation was observed with the other histoprognostic parameters. No statistical link was established with MT1-MMP and TIMP-2. CONCLUSION: Stromal immunolabelling with MMP-2 is a histoprognostic marker of capsular effraction in prostatic adenocarcinoma. When performed on prostatic biopsies, it can predict the pT3 stage, allowing adaptation of the initial treatment in some patients.

Humans↗
PubMed1988

[Interindividual variability in drug metabolism, especially in the elderly. Underlying mechanisms and a possible solution].

The metabolism of a drug reveals a large interindividual variability, which might be attributed to large interindividual differences in the activity of cytochrome P-450 isoenzymes. However, it is difficult to determine this activity in the intact animal or man. With the help of antipyrine, a measure for this activity in man might be possible. Antipyrine is metabolized via 3 metabolic pathways, which are regulated by different isoenzymes of cyt.P-450. In addition, the ratio 6 beta-hydroxycortisol(6 beta-OHF)/17-hydroxycorticosteroids(17-OHCS) in the urine is a measure for the activity of another cyt.P-450 isoenzyme, namely NIF. A correlation between the formation rates of the antipyrine metabolites, hydroxymethylantipyrine and hydroxyantipyrine (OHA) and the clearance of hexobarbital and theophylline, respectively, has been observed. In young volunteers, a good correlation between the formation rate of OHA and the clearance of theophylline have also been found. It must be investigated whether these correlations can also be observed if one smokes, consumes alcohol, keeps diet, takes several drugs, is young or old or is a male or female. If this is the case, the metabolism is predictable, the dose can be adapted and adverse reactions can be prevented, especially in the aged.

Aged↗
PubMedDate not supplied

[Various aspects of the social-psychological selection of flight school applicants].

One hundred and fifty nine applicants who passed entrance examinations and were admitted to the flight school were kept under careful psychological observation and follow-up. It was found that those applicants who grew and developed in unfavorable conditions, i. e. under the influence of risk factors which include young age to start smoking, nervous shocks in childhood and adolescence, unstable family relations, alcoholic parents, etc., failed and were expelled from the school due to different reasons in a greater number of cases (p less than 0.01). Thus professional selection should include accentuated attention to risk factors that accompanied the years of personality formation which may help predict their inadequacies in psychic adaptation to the flying profession.

Adolescent↗
PubMed1980

Critical areas of therapists' functioning in adolescent group psychotherapy: a comparison with self-perception of functioning in adult groups by experienced and inexperienced therapists.

The results of the study's questionnaire has pointed toward some areas of significant differences between experienced and inexperienced therapists in their work with adults and adolescents. These differences appeared to emphasize some techniques and approaches which the experienced therapists have successfully modified for their work with adolescents, and may indicate some important gaps in typical training programs for group therapists. The results have been utilized recently by supervisors in a university affiliated training program for therapists, to predict and focus on trainees' adaptation of general group therapy techniques for work with adolescents. Some directions for further research were also suggested, such as a study of the effect of co-therapists' sex on adolescent group process, and the need for more specific and effective assessment measures of group process and progress in adolescent groups, which could be utilized by therapists at all levels of experience.

Adolescent↗
PubMed1980

A computer simulation model of hospital mergers.

The results of a study and a computer model designed to predict the costs of a potential merger of three hospitals rely on a statistically based cost-prediction model. This model was adapted to reflect several different merger options, and the future costs of the three unmerged hospitals were simulated using a stochastic simulation model.

Computers↗
PubMed1995

Clinical and practical value of human cytomegalovirus DNAemia detection by semi-nested PCR for follow-up of BMT recipients.

The aim of this prospective study of 162 recipients of bone marrow transplantation (BMT) was to evaluate the use of DNAemia detection by semi-nested PCR for the diagnosis of human cytomegalovirus (HCMV) infection and HCMV disease. We compared the results obtained for DNAemia with those obtained for viremia, using the shell vial assay. Patients were divided in three groups, according to BMT type (allogeneic or autologous) and date of transplant; 876 DNAemia/viremia pairs were analyzed and the overall concordance between the two tests was 97.5%. Discrepancies between the two tests were essentially due to the earlier positivity of DNAemia. Among the 10 patients with positive DNAemia episodes, 9 developed HCMV disease. DNAemia was more sensitive than viremia for HCMV disease diagnosis, while viremia had a higher positive predictive value. DNAemia appeared easily adaptable to routine laboratory use, less expensive and more informative than viremia. This study shows that DNAemia is a method that can replace viremia detection, allowing HCMV infection and disease follow-up of recipients of allogeneic BMT during the first year after BMT.

Adolescent↗
PubMed1997

[Indication for percutaneous transluminal coronary angioplasty based on quality of life of patients with angina pectoris].

The changes in quality of life (QOL) before and after percutaneous transluminal coronary angioplasty (PTCA) were investigated to establish criteria for determining whether patients with angina pectoris should undergo PTCA. The QOL was surveyed twice by self-completed questionnaire for QOL by Iida and Kohashi (QUIK) before and about 4 months after PTCA in 84 patients (mean age 62.8 +/- 10.1 years) with angina pectoris. High QUIK score reflects a poor QOL, of which the internal consistency was 0.86, demonstrating high reliability. The subjects were classified into three groups according to the changes of total QUIK score before and after PTCA (I: QOL improved 31.0%, II: QOL unchanged 48.8%, III: QOL worsened 20.2%). Age, gender, total QUIK score prior to PTCA, presence of anginal pain, complications extent and degree of coronary artery stenosis, and left ventricular ejection fraction were compared between the three groups. The total QUIK score prior to PTCA in the improved QOL group was higher than that in the worsened QOL group (11.6 vs 5.1, p < 0.01). Most patients showing a poor QOL prior to PTCA demonstrated an improvement in their QOL after PTCA. The number of patients with anginal pain prior to PTCA was high in the improved QOL group (35.8%, p < 0.05). Percutaneous transluminal coronary angioplasty might not aggravate QOL (12.1%, p = 0.1) in patients with single-vessel disease. In patients with multivessel disease, PTCA might not improve (35.3%) but also might aggravate QOL (25.5%). Multivariate analysis showed that PTCA improved QOL in male or sixty-ager patients and in patients with a total QUIK score of 10 or more prior to PTCA (p < 0.01). The total QUIK score, presence of anginal pain and extent of coronary artery stenosis prior to PTCA, gender and age are factors predicting QOL after PTCA. The adaptation of PTCA for those patients should be prudently and inclusively taken into consideration to extend their QOL.

Adult↗
PubMed1996

The versatile and esthetic metal-ceramic crown.

The predictability, many advantages and remarkable adaptability of metal-ceramic crowns account for their frequent use. Metal-ceramic crowns will continue to be one of the most widely used dental restorations.

Bicuspid↗
PubMed2002

Optimality in the developing vascular system: branching remodeling by means of intussusception as an efficient adaptation mechanism.

The theory of bifurcating vascular systems predicts vessel diameters that are related to optimality criteria like minimization of pumping energy or of building material. However, mechanisms for producing the postulated optimality have not been described so far, and quantitative data on bifurcation diameters during development are scarce. We used an embryonic vascular bed that rapidly grows and adapts to changing hemodynamic conditions, the chicken chorioallantoic membrane (CAM), and correlated vascular cast and tissue section morphology with in vivo time-lapse video monitoring. The bifurcation exponent delta and associated parameters were quantitatively assessed in arterial and venous microvessels ranging in diameter from 30 to 100 microm. We observed emergence of optimality by means of intussusception, i.e., formation of transvascular tissue pillars. In addition to intussusceptive microvascular growth (IMG = expansion of capillary networks) and intussusceptive arborization (IAR = formation of feeding vessels from capillaries) the observed intussusception at bifurcations represents a third variant of nonsprouting angiogenesis. We call it intussusceptive branching remodeling (IBR). IBR occurred in vessels of considerable diameter by means of two alternative mechanisms: either through pillars arising close to a bifurcation, which increased in girth until they merged with the connective tissue in the bifurcation angle; or through pillars arising at some distance from the bifurcation point, which then expanded by formation of ingrowing tissue folds until they became connected to the tissue of the bifurcation angle. Morphologic evidence suggests that IBR is a wide-spread phenomenon, taking place also in lung, intestinal, kidney, eye, etc., vasculature. Irrespective of the mode followed, IBR led to a branching pattern close to the predicted optimum, delta = 3.0. Significant differences were observed between delta at arterial bifurcations (2.70 to 2.90) and delta at venous bifurcations (2.93 to 3.75). IBR, by means of eccentric pillar formation and fusion, was also involved in vascular pruning. Experimental changes in CAM hemodynamics (by locally increasing blood flow) induced onset of IBR within less than 1 hr. Our study provides morphologic and quantitative evidence that a similar cellular machinery is used for all three variants of vascular intussusception, IMG, IAR, and IBR. It thus provides a mechanism of efficiently generating complex blood transport systems from limited genetic information. Differential quantitative outcome of IBR in arteries and veins, and the experimental induction of IBR strongly suggest that hemodynamic factors can instruct embryonic vascular remodeling toward optimality.

Allantois↗
PubMed2003

Secretin activates visceral brain regions in the rat including areas abnormal in autism.

1. The aim of this study was to determine whether central networks are involved in the presumptive behavioral and autonomic regulatory actions of secretin, a gut hormone that has been reported to have ameliorative effects in autistic children. 2. Central neural responses monitored by regional c-fos gene expression were examined in response to intracerebroventricular secretin injection in awake, freely-moving Sprague-Dawley rats. Tissue sections were incubated in an antibody to the c-fos gene product, Fos, and processed immunohistochemically. 3. Qualitative differences in Fos immunoreactivity in stress adaptation and visceral representation areas of the brain were observed between secretin- and vehicle-infused age-matched pairs (n = 4 pairs). Secretin-activated regions include the area postrema, dorsal motor nucleus, medial region of the nucleus of the solitary tract and its relay station in the lateral tegmentum, locus ceruleus, ventral periaqueductal gray, periventricular thalamic nucleus, paraventricular hypothalamus magnocellularis, medial and central amygdala, lateral septal complex as well as ependymal and subependymal nuclei lining the third ventricle. Specific areas of the cerebral cortex were heavily labeled in secretin-treated rats, as compared to controls: the medial bank of the anterior prefrontal cortex, orbitofrontal cortex, the piriform cortex. and the anterior olfactory nucleus. Secretin attenuated Fos immunoreactivity in the dorsal periaqueductal gray, intralaminar thalamus, medial parvicellular compartment of the hypothalamus, supraoptic nucleus of the hypothalamus, lateral amygdala, motor cortex, and the somatosensory and association areas of the parietal cortex. 4. Secretin alters the activity of structures involved in behavioral conditioning of stress adaptation and visceral reflex reactions. This study predicts a possible cellular mechanism, activation of third ventricular ependymal and subependymal cells, as well as central regulatory actions of secretin. The physiological effects of secretin on behavioral, endocrine, autonomic and sensory neuronal activation patterns, together, contribute to central c-fos activation. Secretin alters the activity of structures involved in behavioral conditioning of stress adaptation and visceral reflex reactions. This study predicts a possible cellular mechanism, activation of third ventricular ependymal and subependymal cells, and central regulatory actions of secretin. The physiological effects of secretin on behavioral, endocrine, autonomic and sensory neuronal activation patterns, together, contribute to central c-fos activation. These findings mandate further investigation of secretin as a brain/gut stress regulatory hormone.

Adaptation, Physiological↗
PubMed2004

Use of artificial environments to reproduce and exploit genotype x location interaction for lucerne in northern Italy.

Genotype x environment interaction effects can be exploited by breeding for specific adaptation to well-defined subregions within a target region. Previous work showed that genotype x location interaction for dry matter (DM) yield of lucerne (Medicago sativa L. subsp. sativa) cultivars in northern Italy is large and associated with soil type and level of summer drought stress of locations, suggesting the presence of two contrasting subregions. Thirteen farm landraces collected across the region and four control varieties were evaluated for DM yield in four artificial environments created at one site by the factorial combination of soil type (sandy loam or silty clay) and drought stress level (almost nil or high) for: (1) exploring the possibility to reproduce in artificial environments the adaptation patterns occurring across the region; (2) investigating the adaptation pattern of landraces and its relationship with environmental factors at collecting sites; and (3) providing a preliminary comparison of wide- versus specific-adaptation strategies based on yield gains predicted from selection of populations. Different soils filled large (24.0x1.6x0.8-m deep), bottomless containers in concrete. Water amounts were controlled by irrigation under a moving rain shelter. Cultivars varied largely for adaptation pattern across the artificial environments, mainly due to cultivar x stress interaction. Better response to stress conditions of landraces was closely associated with the level of summer drought at collecting sites (r=0.82), highlighting the importance of evolutionary adaptation. The additive main effects and multiplicative interaction-modelled responses of control cultivars successfully reproduced those observed across locations, candidating the artificial environments as a cheaper alternative to more selection locations when breeding for wide or specific adaptation. The latter implied about 40-50% greater estimated gains relative to breeding for wide adaptation.

Adaptation, Physiological↗
PubMed1998

Defensive functioning predicts improvement in major depressive episodes.

We investigated the predictive effect of psychological defenses on the course of major depression in a subsample of psychiatric patients from a larger study. We tested the hypothesis that a group of eight defenses, associated with depression in previous research, would predict, outcome of major depression. After an intake interview, 37 patients were rated on all DSM-III-R Axes, the SCL-90-R, and 28 defenses, using the Defense Mechanism Rating Scales. At 6-month follow-up interview, SCL-90-R and Global Assessment and Functioning (GAF) were redetermined on 34 (92%), 16 of whom had major depression at intake. Overall Defensive Functioning (ODF) significantly predicted GAF at 6-month follow-up over and above initial level of global functioning and presence of a personality disorder. The group of eight defenses were identified more often (p = .068) in depressed patients who improved less than predicted by their initial functional status. The high adaptive level defense, self-observation, was identified more often in those who improved more than predicted by their initial status. Our findings support the theory of a hierarchy of defenses, and the mediating effects of specific low and high adaptive level defenses on the course of a major depressive episode. Further research should examine passive aggression, acting out, help-rejecting complaining, splitting of self-images, splitting of others' images, projective identification, projection, and devaluation in relationship to the onset, course, and treatment response of depressive disorders.

Adult↗
PubMed2006

Motor adaptation to single force pulses: sensitive to direction but insensitive to within-movement pulse placement and magnitude.

Although previous experiments have identified that errors in movement induce adaptation, the precise manner in which errors determine subsequent control is poorly understood. Here we used transient pulses of force, distributed pseudo-randomly throughout a movement set, to study how the timing of feedback within a movement influenced subsequent predictive control. Human subjects generated a robust adaptive response in postpulse movements that opposed the pulse direction. Regardless of the location or magnitude of the pulse, all pulses yielded similar changes in predictive control. All current supervised and unsupervised theories of motor learning presume that adaptation is proportional to error. Current neural models that broadly encode movement velocity and adapt proportionally to motor error can mimic human insensitivity to pulse location, but cannot mimic human insensitivity to pulse magnitude. We conclude that single trial adaptation to force pulses reveals a categorical strategy that humans adopt to counter the direction, rather than the magnitude, of movement error.

Adaptation, Physiological↗
PubMed2000

Predicting durability of a disease resistance gene based on an assessment of the fitness loss and epidemiological consequences of avirulence gene mutation.

Durability of plant disease resistance (R) genes may be predicted if the cost of pathogen adaptation to overcome resistance is understood. Adaptation of the bacterial blight pathogen, Xanthomonas oryzae pv. oryzae (Xoo), to virulence in rice is the result of the loss of pathogen avirulence gene function, but little is known about its effect on aggressiveness under field conditions. We evaluated the cost in pathogenic fitness (aggressiveness and persistence) associated with adaptation of Xoo to virulence on near-isogenic rice lines with single R genes (Xa7, Xa10, and Xa4) at two field sites endemic for bacterial blight. Disease severity was high in all 3 years on all lines except the line with Xa7. Of two Xoo lineages (groups of strains inferred to be clonally related based on DNA fingerprinting) detected, one, lineage C, dominated the pathogen population at both sites. All Xoo strains were virulent to Xa4, whereas only lineage C strains were virulent to Xa10. Only a few strains of lineage C were virulent to Xa7. Adaptation to virulence on Xa7 occurred through at least four different pathways and was associated with a reduction in aggressiveness. Loss of avirulence and reduced aggressiveness were associated with mutations at the 3' terminus of the avrXa7 allele. Strains most aggressive to Xa7 were not detected after the second year, suggesting they were less persistent than less aggressive strains. These experiments support the prediction that Xa7 would be a durable R gene because of a fitness penalty in Xoo associated with adaptation to Xa7.

Bacterial Proteins↗
PubMed2005

A systematic review of the Charlson comorbidity index using Canadian administrative databases: a perspective on risk adjustment in critical care research.

The Charlson index is commonly used for risk adjustment in critical care health services research. However, the literature supporting this methodology has not been thoroughly explored. We systematically reviewed the literature related to administrative database adaptations of the Charlson index. Our review has 3 major findings. First, 2 studies compared Canadian administrative databases with chart review for obtaining Charlson comorbidity data. Agreement between the database and chart review was substantial (kappa > 0.70), and mortality prediction did not differ. Second, 5 database adaptations were identified with the Deyo and Dartmouth-Manitoba adaptations being most popular. Three studies directly compared these 2 popular adaptations and demonstrated substantial agreement (kappa > 0.70) and similar predictive ability for mortality. Third, one study validated the Charlson index for critically ill patients but demonstrated that APACHE (Acute Physiology and Chronic Health Evaluation) II better discriminates inhospital mortality (area under curve 0.67 vs 0.87). Time and cost barriers prevent widespread use of physiology-based risk adjustment in population-based research. The decreased predictive ability of the Charlson index must be weighed against the advantages of using this instrument for population-based research. Future research should focus on updating the Charlson index for recent changes in the prognosis of comorbid diseases and introduction of International Statistical Classification of Diseases, 10th Revision coding of discharge abstracts.

Canada↗