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PubMedDate not supplied

Relationship of physical symptoms and mood to perceived and actual blood pressure in hypertensive men: a repeated-measures design.

OBJECTIVE: Noncompliance with antihypertensive treatment is a significant health concern. Researchers have suggested that the absence of definable symptoms associated with elevated blood pressure (BP) attenuates patients' motivation to use medication. The current study evaluated the relation of psychological variables, including symptoms, perceptions of BP, and perceptions of medication efficacy, to physiological variables, including actual BP and the use of active antihypertensive medication vs. placebo. METHODS: Participants included 54 mildly hypertensive men who were participating in a placebo-controlled, double-blind study of the quality-of-life effects of antihypertensive therapies. Survey data and BP measurements were obtained during a series of clinic visits. RESULTS: Mixed-model analysis of variance was used to evaluate both between- and within-person relations of psychological to physiological state. Results revealed significant within-person associations between predicted and actual BP. Negative mood was closely related to predicted, but not actual, BP. Participants were also relatively accurate in rating active medications as more effective than placebo. Between-persons analyses did not show relations of symptoms or moods to actual BP. CONCLUSIONS: The significant within-person relations of estimated to actual BP suggest that some individuals may be able to estimate their own BP, although the accuracy of these estimates is limited. The findings may explain patients' belief that they can self-monitor BP. The results have implications for theories of the mental representation of illness and for efforts to improve compliance with antihypertensive therapy.

Adult↗

PubMedDate not supplied

Predicting in-hospital mortality for stroke patients: results differ across severity-measurement methods.

OBJECTIVE: To see whether severity-adjusted predictions of likelihoods of in-hospital death for stroke patients differed among severity measures. METHODS: The study sample was 9,407 stroke patients from 94 hospitals, with 916 (9.7%) in-hospital deaths. Probability of death was calculated for each patient using logistic regression with age-sex and each of five severity measures as the independent variables: admission MedisGroups probability-of-death scores; scores based on 17 physiologic variables on admission; Disease Staging's probability-of-mortality model; the Seventy Score of Patient Management Categories (PMCs); and the All Patient-Refined Diagnosis Groups (APR-DRGs). For each patient, the odds of death predicted by the severity measures were compared. The frequencies of seven clinical indicators of poor prognosis in stroke were examined for patients with very different odds of death predicted by different severity measures. Odds ratios were considered very different when the odds of death predicted by one severity measure was less than 0.5 or greater than 2.0 of that predicted by a second measure. RESULTS: MedisGroups and the physiology scores predicted similar odds of death for 82.2% of the patients. MedisGroups and PMCs disagreed the most, with very different odds predicted for 61.6% of patients. Patients viewed as more severely III by MedisGroups and the physiology score were more likely to have the clinical stroke findings than were patients seen as sicker by the other severity measures. This suggests that MedisGroups and the physiology score are more clinically credible. CONCLUSIONS: Some pairs of severity measures ranked over 60% of patients very differently by predicted probability of death. Studies of severity-adjusted stroke outcomes may produce different results depending on which severity measure is used for risk adjustment.

Adolescent↗

PubMed1986

Kinetics of drug action: an overview.

The intensity and time course of action of directly and reversibly acting drugs are related to and determined largely by the time course of drug and active drug metabolite concentrations in the body. When the pharmacokinetics and the concentration-effect relationship of a drug are known, it is often possible to predict the temporal pattern of its pharmacologic effect(s), including the maximum intensity and duration of action. Sites of action may not be immediately accessible to a drug even if it is injected intravenously; this may be reflected by a gradual increase in the intensity of effect despite decreasing drug concentrations in plasma, with maximum effects occurring later than maximum drug concentrations in plasma. Pharmacologic effects may persist well beyond the time when drug concentrations in plasma are no longer determinable; this is often caused by localization of the drug in an extravascular compartment. Drug distribution kinetics, pharmacologically active metabolites, and development of functional (as opposed to metabolic) tolerance may be responsible for time-dependent changes in drug concentration--pharmacologic effect relationships. Interindividual differences in patients' response to drug therapy may have a pharmacokinetic basis, a pharmacodynamic basis, or both. In clinical assessments of pharmacologic response, it is important to measure the therapeutically relevant effect, to determine interindividual and intraindividual variability, and to explore the possible influence of underlying diseases and other physiologic variables on drug concentration-effect relationships.

Dose-Response Relationship, Drug↗

PubMed1998

Electrocardiographic consequences of a peripatetic lifestyle in gray wolves (Canis lupus).

Cardiac chamber enlargement and hypertrophy are normal physiologic responses to repetitive endurance exercise activity in human beings and domestic dogs. Whether similar changes occur in wild animals as a consequence of increased activity is unknown. We found that free-ranging gray wolves (Canis lupus, n = 11), the archetypical endurance athlete, have electrocardiographic evidence of cardiac chamber enlargement and hypertrophy relative to sedentary captive gray wolves (n = 20), as demonstrated by significant increases in QRS duration, QT interval, and QT interval corrected for heart rate, a tendency towards increased Q, R, and S wave voltages in all leads, and a significant decrease in heart rate. We conclude that exercise activity level and therefore lifestyle affects physiologic variables in wild animals. An immediate consequence of this finding is that physiologic measurements obtained from a captive wild-animal population with reduced exercise activity level may not accurately reflect the normal physiologic state for free-ranging members of the same species.

Adaptation, Physiological↗

PubMed2005

Challenges in presenting high dimensional data to aid in triage in the DARPA virtual soldier project.

One of the goals of the DARPA Virtual Soldier Project is to aid the field medic in the triage of a casualty. In Phase I, we are currently collecting 12 baseline experimental physiological variables and a cardiac gated Computed Tomography (CT) imagery for use in an prototyping a futuristic electronic medical record, the "Holomer". We are using physiological models and Kalman filtering to aid in diagnosis and predict outcomes in relation to cardiac injury. The physiological modeling introduces another few hundred variables. Reducing the complexity of the above into easy-to-read text to aid in the triage by the field medic is the challenge with multiple display solutions. A description of the possible techniques follows.

Computer Simulation↗

PubMed2001

Seasonal variation in fitness variables in professional soccer players.

BACKGROUND: There have been many studies on soccer, but few evaluations of the physiological function of professional soccer players. The aim of this work was to evaluate seasonal variation--from September to February--in anthropometric and physiological variables in a Spanish professional soccer team (n=15). METHODS: Anthropometric measurements were obtained following the standardised techniques adopted by the International Society for the Advancement of Kinanthropometry (ISAK). A maximal treadmill test with breath-by-breath gas analysis was carried out to evaluate the aerobic condition and a Jump test was used to measure muscle performance and strength in the lower limbs. RESULTS: There were no significant variations in body mass, although a statistically significant decrease (p<0.05) in fat percentage and sum of six skinfolds was observed. The somatotype (Heath-Carter) was mesomorphic without any change observed throughout the season. The mean VO2max in the first test (65.5 ml x kg(-1) x min(-1)) had not changed by the second one (66.4 ml x kg(-1) x min(-1)). There were no significant differences in maximal heart rate (185 vs 185 beats x min(-1)) and treadmill speed at VO2max (16.1 vs 15.8 km x h(-1)). At the anaerobic threshold, there were significant differences (p<0.05) in speed (12.4 vs 13.1 km x h(-1)) and heart rate (164 vs 168 beats x min(-1)) as the season progressed. When the data were expressed as a percentage of maximal values obtained, we observed that the speed in the first test was 77 and 83% in the second test. For heart rate, values were 89 and 91%, and for oxygen uptake 77 and 79%. The Jump test did not show any significant change during the season. CONCLUSIONS: We can conclude from these results that professional soccer players have good fitness from the beginning of the Spanish League--with a high VO2max--and the changes observed depend on the initial values.

Adult↗

PubMed2001

Effects of dissolved carbon dioxide on the physiology and behavior of fish in artificial streams.

A new technology for treating waters contaminated with acid mine drainage involves the dissolution of limestone particles using carbon dioxide at pressures above ambient. Because of the fish health risks associated with episodes of high carbon dioxide levels in treated waters, we subjected three species of fish, brook trout (Salvelinus fontinalis), slimy sculpin (Cottus cognatus), and blacknose dace (Rhinichthys atratulus), to 24 h exposures of elevated dissolved carbon dioxide (CO2) at three levels, ranging from 1.0 (low) to 6.3 (high)%, under laboratory conditions. We measured blood physiological variables as well as behavior, including feeding responses, before, during, and after exposure. Physiological responses differed by species, but all species had elevated hematocrits after 1 h of exposure. Brook trout hematocritis were higher at medium and high levels of CO2 than in a control group (0.0% CO2) after 24 h of exposure. Slimy sculpin hematocrits were higher in medium- and high-level exposure groups than in controls after 1 h, but not after 24 h, of exposure. Blacknose dace hematocrits were higher in all three exposure groups than in controls after 1 h but only in medium-level exposure groups after 24 h. Brook trout plasma glucose was significantly higher in medium- and high-level exposure groups after 1 h, and in the high-level group after 24 h, than in controls. Slimy sculpin plasma glucose was not significantly different in elevated CO2 exposure groups from that of controls throughout exposure. Branchial ventilation was significantly greater in all species at elevated CO2 during exposure, indicating stress; however, no difference was observed between treatment and control groups of blacknose dace after 24 h, indicating acclimation. Pectoral fin beats and cough rates were not consistently related to CO2 exposure throughout the study. Brook trout had the longest lasting reaction to stress at lower levels of CO2 among the three species tested. Many of the 11 observed behavioral variables, related to swimming, feeding, social, and illness factors, were affected by elevations of dissolved CO2. Two to seven behavioral variables (18-64% of those measured) were affected by treatment level of dissolved CO2 with a trend by species for the number of variables affected: brook trout > blacknose dace > slimy sculpin. However, behavioral sensitivity to treatment level was greatest in blacknose dace. Recovery to pre-treatment activity rates for most behavior patterns (including feeding) was observed 24 h after cessation of exposure in all three species. Recovery was independent of treatment level, was most rapid in blacknose dace, and was slowest in brook trout. Overall, slimy sculpin was least affected behaviorally by elevated CO2. Although all three species showed stress response and changes in behavior at moderate levels of CO2 (> or = 2%), brook trout and blacknose dace showed evidence of ability to avoid harmful CO2 levels by swimming out of affected waters, whereas the slimy sculpin showed minimal behavioral changes despite remaining in place during exposure. Thus, predation risk and other sources of mortality seem minimal in the event of technological malfunction at a stream treatment site involving the use of CO2 under pressure.

Animals↗

PubMed1979

[Psychophysiological time series study of 54 patients with cardiovascular diseases during rehabilitation. Evaluation, group differences, and periodicities (author's transl)].

In the course of a cardiac rehabilitation program 36 patients with myocardial infarction and 18 patients with functional cardiovascular disorders have been studied for 4 to 6 weeks. Data included daily self-report scales of condition, mood, bodily complaints, and daily routine. Physiological variables (blood pressure, heart rate, ventilation, respiratory gas exchange) were measured three times weekly under different conditions (breath holding, hyperventilation, reaction time, multiple reaction test). Analysis of variance indicated positive effects of the rehabilitation program for physiological as well as psychological variables. There were no obvious differences in state change between groups but there were some differences in the average level of variables. Time series analysis by means of autocorrelations revealed circaseptane periodicities which may be interpreted as a reflection of the exogene weekly rhythms.

Adult↗

PubMed2004

An evaluation of neuroscience nursing research published during the Decade of the Brain.

The purpose of this study was to extend a previous evaluation of neuroscience nursing research to an assessment of the research published during the 1990s--the Decade of the Brain. The evaluation was conducted to assess the focus of neuroscience nursing research and to identify research strategies and scientific methods. The Journal of Neuroscience Nursing, Nursing Research, Research in Nursing & Health, and Western Journal of Nursing Research were canvassed. An assessment form developed by the authors was used to evaluate selected articles published between January 1989 and December 2000. The number of neuroscience research studies published in nursing journals increased substantially during the 1990s. The studies focused more on individuals with neurological disorders and less on neurological trauma. The findings demonstrated major changes in subspecialty area, care orientation, and nature of study variables from that observed in the previous evaluation in which acute care and physiological variables were most representative of the pre-1989 studies. As noted in the previous evaluation, the trend toward theory-then-research studies continued and the scientific methods grew more complex.

Humans↗

PubMed1989

Transmission to the chest of sound introduced at the mouth.

We examined the transmission to the chest wall of white noise and 25-Hz square-wave-generated noise introduced at the mouth of five healthy subjects. The output audio signals were recorded over the left and right upper and lower lung zones, posteriorly. Sound measurements were made during apnea at functional residual capacity, total lung capacity, and residual volume both after breathing air and an 80% He-20% O2 (heliox) gas mixture. We calculated the peak-to-peak amplitude, the peak frequency, and the midpower frequency of the output sound. We found no consistent variations in the values of these indexes due to lung volume or resident gas density. In all cases, the transmitted sound was most intense at the right upper zone. This could not be explained on the basis of technical factors but was probably the result of normal asymmetry of the mediastinal anatomy. These data suggest that sound introduced through the mouth of healthy individuals excites intrathoracic structures but is transmitted through the parenchyma in such a manner that it is not markedly affected by familiar physiological variables. This must be taken into account if objective acoustical tests of lung physiology are to be developed.

Adult↗

PubMed1989

Relationships between microvascular function and capillary structure in diabetic and nondiabetic human skin.

Despite the commonly held view that abnormalities in capillary morphology, in particular thickening of the capillary basement membrane, are partly responsible for diabetic ischemia, few studies have correlated anatomic and hemodynamic variables in the same diabetic subjects. In a previous study of 24 type II (non-insulin-dependent) diabetic subjects and 24 age-matched control subjects, we showed that a standard finger exercise vasodilated cutaneous forearm vessels nearly equally (51%), but the postarteriolar flow responded differently between groups. Nondiabetic subjects increased flow by recruitment of capillaries, whereas diabetic subjects did so by capillary flow augmentation. Moreover, resting permeability-surface area product (PS) to pentetic acid was 85% higher in diabetic than nondiabetic subjects. In this study, these same subjects had their forearm skin biopsied and examined morphometrically by electron microscopy for capillary radius, basement membrane thickness, endothelial cell density, and a folding index of luminal membrane reduplication. All morphological variables were correlated stepwise in a saturated, analysis of covariance model with the physiological results. The correlations were sparse and specifically excluded basement membrane thickness. The highest r2 value was .432 between resting PS and a ratio of capillary density to endothelial cell number per capillary. These studies show little evidence that diabetic microvascular physiological variables are tightly connected to morphometric changes except for minor permeability changes, which rise with capillary density and decrease with endothelial cell number. Because PS to pentetic acid is increased in diabetic subjects at any level of capillary density, it seems reasonable that permeability may be increased above that of nondiabetic subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Capillaries↗

PubMedDate not supplied

Evaluation of variation in oxygen transmission in rigid contact lens extended wear.

Variation in thickness is known to affect the Dk/L of rigid gas permeable contact lenses. Our study was designed to evaluate the variability of central and average thickness of Oxyflow EW lenses. In addition, the relationship between overnight swelling of the central cornea and Dk/L was examined to determine whether Dk/L calculated with central lens thickness correlated better with lens-induced edema than Dk/L calculated with average lens thickness. The results showed marked variation among lens center thicknesses for all powers (-6 D, -2 D, +2 D, +6 D) examined, and, as expected, more variation for centrally calculated Dk/L with high minus lenses. Average Dk/L did not vary significantly with power. Average and central Dk/L values had a near 1:1 relationship for -2 D lenses for the base curve (7.8 mm) ordered; but only when power was kept constant was a good correlation seen between central and average Dk/L. A one-patient study evaluating the overnight central swelling response to three +6 D and three -6 D (high, medium, and low center thickness) lenses showed that central Dk/L correlated better with lens-induced edema than average Dk/L. Thus, specifying central thickness on lens orders appears to be a primary variable influencing extended wear edema at night. Peripheral Dk/L, however, may influence corneal physiological variables other than central edema and warrants further study.

Adult↗

PubMed1990

[Measuring psychophysiologic variables during conversations. Quantifying pulse volume changes].

Little is known about connections between events in verbal communication and related physiological variables. Usually used procedures in quantification of pulsevolume data are based on simplifications neglecting essential characteristics of the curve between heart beats. It is shown that the concept of interbeat-intervals (IBI) underlying conventional methods hides these characteristics putting up with a delay in time between heart beats and related verbal factors. An alternative procedure of the extraction of period and amplitude is demonstrated. A software-package is developed to transform and interactively control the analysis of the pulsevolumesignal (filtering and vector-transformation). As results quasi-continuous time series of period and amplitude of the pulsecurve are shown, tracing the shape of the curve in each cardiac cycle. Some first applications of the method in stress research are discussed. The method is appropriate especially for detecting "short time" changes of cardiac activity in naturalistic observational settings (e.g. dyadic interaction).

Arousal↗

PubMed1996

Using severity measures to predict the likelihood of death for pneumonia inpatients.

OBJECTIVE: To see whether predictions of patients, likelihood of dying in-hospital differed among severity methods. DESIGN: Retrospective cohort. PATIENTS: 18,016 persons 18 years of age and older managed medically for pneumonia; 1,732 (9.6%) in-hospital deaths. METHODS: Probability of death was calculated for each patient using logistic regression with age, age squared, sex, and each of five severity measures as the independent variables: 1) admission MedisGroups probability of death scores; 2) scores based on 17 admission physiologic variables; 3) Disease Staging's probability of mortality model; the Severity Score of Patient Management Categories (PMCs); 4) and the All Patient Refined Diagnosis-Related Groups (APR-DRGs). Patients were ranked by calculated probability of death; 5) rankings were compared across severity methods. Frequencies of 14 clinical findings considered poor prognostic indicators in pneumonia were examined for patients ranked differently by different methods. RESULTS: MedisGroups and the physiology score predicted a similar likelihood of death for 89.2% of patients. In contrast, the three code-based severity methods rated over 25% of patients differently by predicted likelihood of death when compared with the rankings of the two clinical data-based methods [MedisGroups and the physiology score]. MedisGroups and the physiology score demonstrated better clinical credibility than the three severity methods based on discharge abstract data. CONCLUSIONS: Some pairs of severity measures ranked over 25% of patients very differently by predicted probability of death. Results of outcomes studies may vary depending on which severity method is used for risk adjustment.

Adolescent↗

PubMed1985

Biopsychosocial studies on cutaneous malignant melanoma: psychosocial factors associated with prognostic indicators, progression, psychophysiology and tumor-host response.

A series of seven studies investigating biopsychosocial aspects of cutaneous malignant melanoma were conducted by a multidisciplinary group of researchers at the University of California, San Francisco. Two studies investigated the relationship of variables derived from a videotaped psychosocial interview and from self-report measures, and two histopathologic indicators: tumor thickness and level of invasion. Associations of psychosocial variables to prognostic indicators were stronger within the younger vs the older subject group. In a multiple regression analysis, patient delay in seeking medical attention emerged as the most significant variable predicting tumor thickness. A study of factors related to patient delay found longer delays in patients who had lesions on the back, less previous knowledge of melanoma, less understanding of its treatment and less minimization of its seriousness. Another study compared the repressive coping reactions--defined as the discrepancy between reported anxiety and that reflected in electrodermal activity--in melanoma patients, cardiovascular disease patients and disease-free controls. The melanoma group was significantly more 'repressed' on the combined self-report/physiological measure, as well as on other self-report measures of repressiveness. In order to investigate the relationship of psychosocial factors to more disease-relevant physiological variables, the next study focused on two clinical variables significantly predictive of disease outcome:mitotic rate of the tumor and lymphocytes at tumor site. Emotional expression of sadness and anger, rated from the videotaped interviews, was positively correlated with tumor-specific host-response factors and negatively correlated with mitotic rate. In another study, subjects who had died or had disease progression were matched on the basis of tumor and demographic characteristics with subjects who had no evidence of disease by follow-up. The unfavorable outcome group had higher scores on self-report scales of dysophoric emotion and distress which were administered one to three years previously. An experimental investigation of relationships among behavioral, physiological and tumor outcome variables in the Syrian hamster found that general activity was correlated positively with greater tumor growth following induction. These results were compared to those from the preceeding two human studies, and discussed in terms of a stress-arousal-coping model.

Adaptation, Psychological↗

PubMed1978

Multivariate interrelationships of selected physiological and biochemical variables associated with physical fitness status.

The interrelationships between selected physiological, metabolic and hormonal variables were investigated in active and sedentary middle-aged males during consecutive periods of rest, graded exercise on a bicycle ergometer, and recovery. Venous blood samples were drawn during each phase of the activity which was performed in the post-absorptive state. Data were analysed using correlational and factorial analysis techniques, and further evaluated by discriminant function procedures. Significant correlational relationships were evident among physiological, metabolic and hormonal variables, and factor analysis identified four factors at each phase of activity which accounted for as much as 69% of the common extracted variance. These factors described physiological function and hormone-metabolite behaviour during each phase of activity. Discriminant function allowed fitness classification of subjects using only the hormone-metabolite data, thus identifying specific biochemical correlates of the fitness groupings which had been established by physiological criteria alone.

Adrenal Cortex Hormones↗

PubMed1995

Genetic analysis of the relationships between behavioral and neuroendocrine traits in Roman High and Low Avoidance rat lines.

In order to determine whether the coselection observed between the selection trait (active avoidance behavior) of the Roman High Avoidance (RHA) and Roman Low Avoidance (RLA) rat lines and their neuroendocrine characteristics were genetically determined, we analyzed, in nonsegregating (RHA, RLA, and F1) and segregating (F2 and the two backcrosses) crosses, the inheritance pattern and the phenotypic correlations among behavioral (shuttle-box behavior), physiological (body, adrenal, and thymus weights), and neuroendocrine (corticosterone and prolactin reactivity, catecholamine enzyme activities) variables. Physiological characteristics and enzyme activities have a crucial role in sex dissociation. Avoidance behavior and prolactin reactivity to novel environment remained associated in segregating crosses despite gene rearrangement. They represented the most important variables to differentiate the Roman lines, perhaps sharing a common regulatory mechanism under genetic control.

Animals↗

PubMed1996

Cardiac frequency in miners recorded during four to five work shifts.

Cardiac frequency (fc) was recorded in 101 coal-face miners [mean age 32.7 (range 21-49) years, mean height 169.6 (range 150-185) cm, mean body mass 76.9 (range 54-106) kg, mean maximal cardiac frequency (fcmax) 180.2 (range 154-197) beats min-1, mean maximal oxygen uptake (VO2max) 2.93 (range 1.9-4.0) 1.min-1] with a small-size, nonintrusive fc counter, during the five (n = 76) or at least four (n = 25) work-shifts in a week. The femax and VO2max were determined during a progressive test to exhaustion on a treadmill. Overall (four to five work-shifts) mean work-time fc(fc) was 97.7 (range 74.9-122.4) beats.min-1, resting fc (fcrest) 59.1 (range 50-75) beats.min-1, work-time increase in fc (fc-fcrest) 38.5 (range 21.1-55.8) beats.min-1 and percentage of fe reserve used (fcreserve = fcmax-fcrest) 32.0 (range 18.5-50.9). Multiple regression analysis showed that fc and fc-fcrest, as dependent variables, correlated with predicted percentage of CO lung diffusion capacity, (DLCOSB%) (r = - 0.334 and r = -0.273, respectively) but not with age, fcmax, VO2max, VO2max kg-1 body mass, effort test delta oxygen uptake/delta fe or percentage of forced expiratory volume in 1 s as independent variables. The percentage of fcreserve used as dependent variable, correlated with DLCOSB (r = -0.265) and fcmax (r = -0.227) but not with any of the other variables listed. Individual differences in worktime fc are thus large and virtually unpredictable. Other physiological variables not taken in account here (i.e. sense of effort, fatigue perception) as well as psychological ones (work satisfaction, motivation) may have played a role in those differences. At peaks of effort, some subjects reached fc values within the range of femax.

Adult↗