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PubMed2003

Gender and status asthmaticus.

BACKGROUND: Adult women may be more susceptible to asthma than men. HYPOTHESIS: Women are more likely to develop status asthmaticus (SA) requiring critical care. METHODS: The medical records of patients admitted to our medical intensive care unit (ICU) for SA between 1994 and 2000 were examined. A number of demographic and physiologic variables were extracted from the medical records. RESULTS: Of 103 total admissions, 53 (of 37 patients) were age < 50 years and had clinical evidence suggesting SA. Among these 37 patients, the average (+/-SE) age was 30.8 +/- 1.0 y with average acute physiology and chronic health evaluation (APACHE) II of 9.5 +/- 0.8. Seventeen patients were Hispanic, 13 were black, and 7 were white. Twenty-four patients (accounting for 37 admissions) were female and 13 patients (16 admissions) were male. Although women accounted for a greater absolute number of endotracheal intubations (ETI; 17 vs. 12) and were more likely to be admitted to ICU more than once (7 vs. 3), men had a higher incidence of ETI (RR=1.6; 95%CI=1.04-2.6). The need for using therapeutic permissive hypercapnia and lengths of stay (ventilator, ICU, and hospital) were similar between men and women. Two patients, both women, died of causes not related to treatment of SA. CONCLUSIONS: These data suggest that although women accounted for more ICU admissions for SA, men were more likely to require ETI.

Adult↗

PubMed1993

Colon cancer--do the nutritional epidemiology, the gut physiology and the molecular biology tell the same story?

Colon carcinogenesis models exist at epidemiologic, physiologic and molecular biologic levels. Thinking about the coherence of such models is useful both to inform colon cancer research and because the reasoning process may be generalizable. The consistent epidemiologic risk factors are low vegetable/fiber and high fat/meat/protein intakes. Others include physical activity, alcohol and reproduction. These epidemiologic risk factors appear to map to physiologic variables that provide mechanistic explanations for the associations: higher bile acids, fiber fermentation and effects of specific anticarcinogens found in vegetables. The possibility that the meat/fat association is due to carcinogens or promoters produced in cooked foods adds complexity to the physiologic model. As a link across genetics, physiology and epidemiology, the role of acetylator status is considered. Finally, whether relationships might exist between the epidemiologic/physiologic risk factors and the recently described molecular genetic changes and other colon cancer molecular mechanisms is considered.

Colonic Neoplasms↗

PubMed1992

Perioperative myocardial ischemia and infarction. Prophylaxis and treatment of ischemia.

Protection from and treatment of myocardial ischemia involves detection and recognition of early changes in myocardial function associated with ischemia, as well as use of techniques and agents designed to alleviate or ameliorate ischemia. However, decisions regarding which agent(s) to employ depend upon not only the effects of a particular therapy but also the interaction(s) among the therapeutic agents and anesthetics. All the drugs and treatments discussed above may have beneficial effects in conscious patients but variable degrees of effectiveness during anesthesia. The choice of agents to be used for myocardial protection ultimately depends upon clinical decisions regarding coronary blood supply and myocardial oxygen demand. The availability of several different classes of agents capable of altering specific physiological variables allows a wide variety of clinical situations to be effectively managed.

Cardiotonic Agents↗

PubMedDate not supplied

Cluster analyses of cardiovascular responsivity to three laboratory stressors.

Seventy-three young normotensive male subjects were tested with an experimental protocol that included a reaction time, a mental arithmetic, and a cold pressor task. Physiological variables that were recorded included heart rate, stroke volume, pre-ejection period, blood pressure, total peripheral resistance, and respiratory sinus arrhythmia. In order to identify subgroups of subjects who differed in their pattern of autonomic responses to the tasks, the physiological change scores from baseline to the tasks for each subject were entered into a cluster analysis for each task. Ward's method was used as the clustering algorithm. The cluster analyses identified four clusters for the reaction time and mental arithmetic tasks, and five clusters for the cold pressor task. Although there was a wide range of patterns exhibited by cluster subgroups, most subjects who were reactive to the tasks showed response patterns that were qualitatively similar to the pattern of overall mean response by all subjects, albeit varying considerably in terms of quantitative response. Little evidence was generated for the consistency of extreme beta-adrenergic response from one task to another, although significant consistency was noted when milder beta-responders were included in the comparisons. Some consistency of alpha-adrenergic response noted across tasks, as well as significant consistency of being relatively nonreactive to the tasks.

Adult↗

PubMed2005

Electrical stimulation of unloaded muscles causes cardiovascular exercise by increasing oxygen demand.

BACKGROUND: The development of new strategies to encourage increased levels of physical activity can help to reduce the incidence of cardiovascular disease. A new system of electrical muscle stimulation (EMS) has been developed that attempts to cause an increase in energy expenditure by mimicking the action of shivering in the body. The purpose of this study was to show that this form of EMS is capable of eliciting a cardiovascular exercise response in healthy adults. DESIGN: An observational study. METHODS: Ten healthy volunteers completed a maximal treadmill test and four EMS sessions using a hand-held EMS device that delivered current to the body via five silicone rubber electrodes on each leg. At each session subjects completed 3 min stimulation at each of four stimulation outputs (10, 20, 30 and 40% of maximum output) while cardiopulmonary gas exchange and heart rate (HR) were measured. Physiological responses at increasing levels of stimulation were evaluated. RESULTS: Average (+/-SD) HR and oxygen consumption (VO2) levels of 67+/-11 bpm and 4.7+/-1.2 ml/kg per min at rest, respectively, were increased to 186+/-10 bpm and 44.9+/-9.8 ml/kg per min at peak exercise intensity on treadmill testing. The electrical stimulation was generally well tolerated by the subjects. Subjects demonstrated statistically significant increases in all physiological variables measured with successive increases in stimulation intensity. Peak HR and VO2 at 40% stimulation intensity were 101+/-12 bpm and 14.9+/-4.3 ml/kg per min, respectively. CONCLUSIONS: These results demonstrate that this form of EMS is capable of producing a physiological response consistent with cardiovascular exercise at mild to moderate intensities. It achieves this without producing gross movement of the limbs or loading of the joints. This EMS-induced cardiovascular exercise response could be used to promote increased levels of physical activity in populations unable to participate in voluntary exercise.

Adaptation, Physiological↗

PubMed2000

Acute respiratory failure after lung volume reduction surgery.

In this study, we characterized patients who developed respiratory failure postoperatively after lung volume reduction surgery (LVRS). We retrospectively reviewed the records of 72 patients who underwent LVRS from February 1995 to February 1998, examining perioperative variables and complications. Twenty-one patients (29%) developed postoperative respiratory failure, five due to hypoxemia, nine due to hypercapnia, and seven secondary to hemodynamic instability. The hospital mortality was 33% among patients who developed respiratory failure. No preoperative clinical or physiologic variable (including percent ideal body weight, serum albumin, prednisone use, lung function, maximal O(2) uptake on exercise testing, 6-min walk distance, and hemodynamic parameters) was predictive of postoperative respiratory failure. Patients who developed respiratory failure were older (63 +/- 7 versus 57 +/- 8 yr, p = 0.01), had longer anesthesia time (188 +/- 96 versus 127 +/- 56 min, p = 0.001), had a higher incidence of coronary artery disease (40% versus 10%, p = 0.001) and performance of concomitant surgical procedures during the LVRS operation (40% versus 2%, p < 0.001) compared with those without respiratory failure. All patients who underwent simultaneous surgery, which were mostly for cardiac disease, developed respiratory failure. Risk factor analysis confirmed that older patients and those undergoing cardiac surgery combined with LVRS are at increased risk for postoperative respiratory failure.

Aged↗

PubMed1990

Microcomputer-based data acquisition system for clinical research.

We have described a computerized data acquisition system for clinical investigation that can record over fifty physiologic variables from up to twenty-four electronic monitors. The information is acquired by a personal computer using RS-232C serial communications and analog-to-digital conversion. In its present configuration the system records information from a Spacelabs 500 series physiologic monitor, Hewlett-Packard physiologic monitor with the Careport computer interface, SARA mass spectrometer, Nellcor pulse oximeter, Neurotrac processed EEG, Lawrence cardiac output monitor, Hewlett-Packard capnometer, and Bourns spirometer. The software can be easily modified to accommodate other physiologic monitors. The system records parameter or waveform information and writes the data into a file that can be accessed by commercially available graphical and statistical packages. The data acquisition system is easy to use, transportable, and inexpensive.

Humans↗

PubMed2006

Systems-based medicine approaches to understand and treat complex diseases. The example of multiple sclerosis.

Systems medicine is an emerging concept that acknowledges the complexity of a multitude of non-linear interactions among molecular and physiological variables. Under this new paradigm, rather than a collection of symptoms, diseases are seen as the product of deviations from a robust steady state compatible with life. This concept requires the incorporation of mathematics and physics to the more classical arsenal of physiology and molecular biology with which physicians are trained today. This review explores the diverse types of information that can be accumulated towards the understanding of multiple sclerosis (MS), a complex autoimmune disease that targets the central nervous system (CNS). The challenge of data integration and modeling of dynamical systems is discussed in the context of disease susceptibility and response to treatment. A theoretical framework that supports the use of combination therapy is also presented.

Animals↗

PubMed1991

Behavioral aspects of stress.

Many researchers view stress theory as having evolved from a specific response for each specific stimulus, through a standardized general adaptation syndrome for a wide variety of stressors, to a newly hypothesized model that suggests a standardized physiological response for psychological stressors and specific homeostatic responses for physical stressors. Stressors can originate from within an individual (endogenous) or from the environment (exogenous). A sense of control over one's environment (exogenous stimuli) and predictability of stimuli are extremely important in determining the potency of psychological stressors. The performance of highly repetitive, stereotyped behaviors has been shown to help animals cope with environments containing little or unvaried stimulation. Chronic psychological stressors are the most problematic area of stress research and animal care. Animals may respond behaviorally to chronic stressors by either achieving adaptation or by showing such conditions as learned helplessness, intensification of drives, stereotyped behavior, and absence of normal behaviors. A chronic endogenous buildup of motivation to perform specific behaviors that an animal has been prevented from performing can be quantified and result in animals displaying signs of chronic stress, i.e., altered metabolism (hormones), suppressed immune system, and learned helplessness. It is of paramount importance that the behavioral and physiological variables utilized in stress research be relevant to the particular species and questions under study.

Acute Disease↗

PubMed2001

[Epistaxis and circadian rhythm].

It is known that many physiological variables show a rhythmic variability along a time span, e.g.: day, week, month or year. It is possible that the temporal overlapping of a constellation of factors may act as favouring and/or triggering factors for the onset of several acute diseases. Among these, epistaxis shows a circadian variability too. Such pattern, characterised by a prevalent peak in the morning and a secondary one in the evening, strictly resembles that of arterial blood pressure. The lack of differences between the temporal pattern of hypertensive and normotensive subjects suggests that the physiological pattern of blood pressure, and not strictly a condition of hypertension, may play a favouring role in certain hours of the day, probably together other local factors.

Circadian Rhythm↗

PubMedDate not supplied

Ultradian rhythms in the EEG and task performance.

The purpose of this work was to investigate the presence of ultradian rhythms in: 1. levels of electroencephalographic activation; 2. interhemispheric correlation and 3. the performance of two cognitive tasks, and the correlation between these variables. Eight volunteers, aged 20 to 30, participated in the experiment. Two sessions were carried out: one from 0800 to 1400 on one day and the other from 1400 to 2000 another day. Samples of EEG activity were taken every 15 min at rest with eyes open in left and right temporal, central, parietal and occipital derivations referred to the ipsilateral earlobe the performance on two tasks, one logico-analytical (left hemisphere functions) and one spatial test (right hemisphere functions) was assessed. As control, body and environmental temperature were recorded. To test for the presence of ultradian rhythms, the data were subjected to a Fourier analysis. Different EEG variables showed rhythmicity throughout the sessions, principally with slow oscillation periods (3 and 6h); ultradian rhythms with 3h periods were also found in body temperature, while task performance showed no significant rhythmic patterns during sessions. Finally, no significant correlations were found between physiological variables evaluated and task performance.

Activity Cycles↗

PubMed2006

Manipulating high-intensity interval training: effects on VO2max, the lactate threshold and 3000 m running performance in moderately trained males.

The aim of this study was to compare the effects of two high-intensity interval training (HIT) programmes on maximal oxygen uptake (.VO(2max)), the lactate threshold (LT) and 3000 m running performance in moderately trained male runners. .VO(2max), the running speed associated with .VO(2max) (V.VO(2max)), the time for which V.VO(2max) can be maintained (T(max)), the running speed at LT (v(LT)) and 3000 m running time (3000 mTT) were determined before and following three different training programmes performed for 10 weeks. Following the pre-test, 17 moderately trained male runners (V O(2max)=51.6+/-2.7ml kg(-1)min(-1)) were divided into training groups based on their 3000 mTT (Group 1, G(1), N=6, 8 x 60% of T(max) at V.VO(2max), 1:1 work:recovery ratio; Group 2, G(2), N=6, 12 x 30s at 130% V.VO(2max), 4.5 min recovery; control group, G(CON), N=5, 60 min at 75% V.VO(2max)). G(1) and G(2) performed two HIT sessions and two 60 min recovery run sessions (75% V.VO(2max)) each week. Control subjects performed four 60 min recovery run sessions (75% V.VO(2max)) each week. In G(1), significant improvements (p<0.05) following HIT were found in .VO(2max) (+9.1%), V.VO(2max) (+6.4%), T(max) (5%), v(LT) (+11.7%) and 3000 mTT (-7.3%). In G(2), significant improvements (p<0.05) following HIT were found in .VO(2max) (+6.2%), V.VO(2max)(+7.8%), T(max) (+32%) and 3000 mTT (-3.4%), but not in v(LT) (+4.7%; p=0.07). No significant changes in these variables were found in G(CON). The present study has shown that 3000 m running performance, .VO(2max), V.VO(2max), T(max) and v(LT) can be significantly enhanced using different HIT programmes in moderately trained runners, but that changes in performance and physiological variables may be more profound using prolonged HIT at intensities of V.VO(2max) with interval durations of 60% T(max).

Adult↗

PubMedDate not supplied

[Psychological factors of non-ulcer dyspepsia].

Given the absence of any demonstrable organic reason for non-ulcer dyspepsia, and the well known fact, that the psyche influences stomach function, it is widely held, that psychological factors cause NUD. To now, studies are concerned with the psychopathology and personality of NUD-patients, their illness behaviour, and with the relation between stress and abdominal pain. A critical review of these studies revealed, that among the psychological variables mainly anxiety and illness behaviour seems to play a central role in NUD. However, future studies should focus more on the distinction towards other functional disorders and on the differentiation within the heterogeneous group of NUD-patients (especially with regard to physiological variables). Besides this, it seems rewarding to examine the so far scientifically neglected group of subjects with abdominal pain, who do not contact a physician.

Abdominal Pain↗

PubMed1989

The impact of previous athleticism on exercise habits, physical fitness, and coronary heart disease risk factors in middle-aged men.

A longitudinal study was performed to determine differences in physiologic variables, health behaviors, risk factors, or clinical status between former athletes (FA) (N = 345) and nonathletes (NA) (N = 75). The subjects, 420 self-referred white males aged 25-60 years old, were examined for prior athleticism and health. Athleticism was determined through self-reported high school or college athletic history. Baseline physiologic and health behavior characteristics were not different between the two groups. Of those study participants (N = 203 FA, 48 NA) who were sedentary at baseline, 208 (N = 167 FA, 41 NA) voluntarily began an exercise program during the followup period (average followup = 56 months). These numbers correspond to exercise adoption rates of 82 and 85% for FA and NA respectively, and were not statistically different (95% CI FA = 0.76, 0.88, NA = 0.73, 0.97). Repeated measures analysis of covariance was performed to determine if physiologic responses to adoption were different between FA and NA. No statistically significant difference was found between the two groups, time effects were similar in the two, and no significant interaction of time by group was observed. We conclude that prior athleticism has little apparent impact on health and health behaviors, thus suggesting that contemporaneous exercise has more impact on clinical variables.

Adult↗

PubMed2006

Exploration of statistical dependence between illness parameters using the entropy correlation coefficient.

UNLABELLED: The entropy correlation coefficient (ECC) is a useful tool for measuring statistical dependence between variables. We employed this tool to search for pairs of variables that correlated in the chronic fatigue syndrome (CFS) Computational Challenge dataset. Highly related variables are candidates for data reduction, and novel relationships could lead to hypotheses regarding the pathogenesis of CFS. METHODS: Data for 130 female participants in the Wichita (KS, USA) clinical study [1] was coded into numerical values. Metric data was grouped using Gaussian mixture models; the number of groups was chosen using Bayesian information content. The pair-wise correlation between all variables was computed using the ECC. Significance was estimated from 1000 iterations of a permutation test and a threshold of 0.01 was used to identify significantly correlated variables. RESULTS: The five dimensions of multidimensional fatigue inventory (MFI) were all highly correlated with each other. Seven Short Form (SF)-36 measures, four CFS case-defining symptoms and the Zung self-rating depression scale all correlated with all MFI dimensions. No physiological variables correlate with more than one MFI dimension. MFI, SF-36, CDC symptom inventory, the Zung self-rating depression scale and three Cambridge Neuropsychological Test Automated Battery (CANTAB) measures are highly correlated with CFS disease status. DISCUSSION: Correlations between the five dimensions of MFI are expected since they are measured from the same instrument. The relationship between MFI and Zung depression index has been previously reported. MFI, SF-36, and Centers for Disease Control and Prevention (CDC) symptom inventory are used to classify CFS; it is not surprising that they are correlated with disease status. Only one of the three CANTAB measures that correlate with disease status has been previously found, indicating the ECC identifies relationships not found with other statistical tools. CONCLUSION: The ECC is a useful tool for measuring statistical dependence between variables in clinical and laboratory datasets. The ECC needs to be further studied to gain a better understanding of its meaning for clinical data.

Adult↗

PubMed1990

Target animal safety test of a dexamethasone-prednisolone combination in horses.

The target animal safety of a dexamethasone-prednisolone combination was studied on 12 horses divided into two groups of six each. One group of horses received the therapeutic dose of the combination (25 mg/animal dexamethasone pivalate and 75 mg/animal prednisolone) and the second group was given the threefold dose of it. The preparation was administered intravenously for 2 consecutive days. For assessment of safety a wide range of clinical, haematological, biochemical and urine variables were tested as laid down in the guidelines of the FDA. All horses treated by the therapeutic or the threefold therapeutic doses of the preparation remained in good health throughout the entire study. No signs of clinical abnormalities occurred in either group. The physiological variables tested failed to reveal any significant alteration as a consequence of the medications. Of the haematological and biochemical parameters leucocyte, neutrophil, eosinophil and lymphocyte counts, aspartate aminotransferase activity, glucose, phosphor, total and conjugated bilirubin and creatinine concentrations were significantly affected in both groups. In some animals a transient glucosuria occurred. From the direction and magnitude of these changes it was concluded that they did not reflect any toxic actions of the preparation. Nevertheless, the combination is to be administered only with exact therapeutic indications and the uncontrolled misuse of it must be avoided.

Animals↗

PubMed1997

Preference among cooling systems by gilts under heat stress.

A preference experiment was conducted to compare and evaluate the use of three cooling systems by mature gilts. Systems evaluated were snout coolers (S), drip coolers (D), and conductive cool pads (P). Preference for cooling system and pen position were continuously monitored and evaluated during daily heat stress conditions (34.2 +/- 2.8 degrees C), nightly warm conditions (26.6 +/- 2.3 degrees C), and for total time. The physiological variables of respiration rate (RR) and rectal temperature (Tr) were measured at three separate times daily. Gilts naive to the cooling systems were individually housed in pens with three free stalls, each stall containing a different cooling system. After 1 d of warm temperature (27.6 +/- 2.5 degrees C) acclimation, gilts were exposed to 10 h of the heat stress conditions and 14 h of the warm night conditions each day for six consecutive days. Cooling system use was higher during the hot period (80.2%) than during the warm period (66.2%). The conductive cool pad was preferred over the drip cooler (P < .02) and the snout cooler (P < .0002). The preference for the conductive cool pad persisted in the warm period. Cooling system use had a significant effect on Tr and RR (P < .001). The Tr (P < .005) and RR were lower (P < .005) with the use of the conductive cool pad, whereas the drip cooler and snout cooler showed no effect on these variables.

Animal Welfare↗

PubMed1995

Using physiologic end points to assess innovations in mechanical ventilation.

It is our view that new ventilatory methods should be withheld from clinical practice until there has been adequate evaluation of their effect on physiologic variables and the link to long-term outcomes has been established. In the past, premature and over-enthusiastic acceptance of ventilatory strategies may have resulted in patient discomfort and even harm, and this can be minimized by a more careful evaluation of the physiologic effects of such innovations before their acceptance into clinical practice.

Diffusion of Innovation↗