Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “REST”

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 451 records · Page 25Linked to original sources
PubMed1996

Young children's cardiovascular stress responses predict resting cardiovascular functioning 2 1/2 years later.

BACKGROUND: Since the pathogenesis of coronary heart disease (CHD) has its origins in childhood, researchers have increasingly evaluated CHD risk factors in youth. In this study we examined the hypothesized behavioral risk factor of cardiovascular responsivity as a predictor of very young children's resting cardiovascular functioning 2 1/2 years later. SUBJECTS AND METHODS: During an initial visit to the laboratory, 97 children (30 blacks and 67 whites, 45 boys and 52 girls) aged 6-7 years completed three laboratory stressor tests (forehead cold pressor, postural change, and treadmill exercise). A comprehensive cardiovascular assessment was conducted during the tests. Resting cardiovascular activity (baseline values) was also assessed. Follow-up resting cardiovascular parameters were measured in the laboratory 2 1/2 years later. RESULTS: Cardiovascular stress responses were predictive of cardiovascular follow-up resting levels 2 1/2 years later. Multiple regression was used to evaluate the independent predictive power of stress responses after controlling for traditional risk factors. Follow-up resting systolic blood pressure (SBP) was predicted by the SBP response to postural change and treadmill exercise. Follow-up resting diastolic blood pressure (DBP) was predicted by the DBP response during treadmill exercise, particularly for blacks. The follow-up resting heart rate was predicted by the heart rate response to the forehead cold pressor and treadmill exercise. CONCLUSION: These results show that in very young children, stress responses are predictive of resting cardiovascular functioning 2 1/2 years later. Further developmental and longitudinal investigations will determine whether such responses are predictive of later preclinical manifestations of cardiovascular disease. If so, incorporation of stress testing in a standardized risk identification protocol might aid the design and practice of cardiovascular preventive medicine.

Analysis of Variance↗
PubMed1998

Rest-redistribution thallium-201 SPECT to detect myocardial viability.

UNLABELLED: Rest-redistribution 201Tl imaging is currently being used for myocardial viability detection, but the ideal parameters for territory classification have not yet been defined. The aim of this study was to define the optimal criteria for detecting viable myocardium and predicting postrevascularization recovery with rest-redistribution 201Tl SPECT. METHODS: In 29 patients with left ventricular dysfunction, tracer activity within asynergic segments was quantified on rest and redistribution 201Tl SPECT. Viability was defined by the presence of functional recovery, which was detected by comparing wall motion in baseline and follow-up echocardiography. Discriminant function analysis and receiver operating characteristic (ROC) curve analysis were used to evaluate the relationship between 201Tl data and viability. RESULTS: Of 214 dysfunctioning segments (135 a-/dyskinetic), viability was demonstrated in 115 (75 a-/dyskinetic). Both rest and redistribution 201Tl activity in these segments were significantly higher than they were in the nonviable segments (p < 0.0001). Significant (> 10%) reversibility was observed in 39% of the viable and in 36% of the nonviable segments (p = 0.81). Discriminant analysis identified redistribution activity, followed by rest activity, as the most effective predictors of functional recovery. Similar areas were found under the ROC curve for rest (0.68 +/- 0.037) and for redistribution activity (0.70 +/- 0.036) (p = 0.13). ROC curve analysis identified the optimal cutoff for redistribution activity at < 60%, with 147 of 214 (69%) segments correctly classified (sensitivity = 78% and specificity = 58%). In the subset of a-/dyskinetic segments, redistribution activity presented a significantly larger ROC curve area (0.81 +/- 0.038 compared to 0.77 +/- 0.042, p < 0.05), and 103 of 135 (76%) segments were correctly classified (sensitivity = 81% and specificity = 70%). CONCLUSION: Redistribution activity is the most important parameter to be considered in rest-redistribution 201Tl to differentiate viable from nonviable segments; rest activity is also valuable, whereas the meaning of reversibility appears limited. Cutoff values about 60% appear to give the most reasonable balance between sensitivity and specificity.

Coronary Angiography↗
PubMed1998

Inverse expression pattern of REST and synapsin I in human neuroblastoma cells.

The zinc finger protein REST is a repressor of neuronal genes in nonneuronal tissues. We have analyzed the expression of REST, together with the expression of a REST target gene, encoding synapsin I, in human neuroblastoma cells. It was found that REST and synapsin I are coexpressed in neuroblastoma cell lines, although the expression of REST was inversely proportional to the levels of synapsin I mRNA. Thus, increased expression of synapsin I was directly correlated with decreased expression of REST. These expression data are in excellent correlation with synapsin I promoter activity measured in neuroblastoma cells showing that an increase in the REST concentration switched off synapsin I promoter activity. We conclude that the concentration of REST determines the expression level of neuronal genes such as the synapsin I gene.

Gene Expression↗
PubMed2006

The long-term prognostic value of the resting and postexercise ankle-brachial index.

BACKGROUND: Peripheral arterial disease is associated with a high incidence of cardiovascular mortality. Peripheral arterial disease can be detected by using the ankle-brachial index (ABI). This study assessed the prognostic value of the postexercise ABI in addition to the resting ABI on long-term mortality in patients with suspected peripheral arterial disease. METHODS: In this prospective cohort study of 3209 patients (mean +/- SD age, 63 +/- 12 years; 71.1% male), resting and postexercise ABI values were measured and a reduction of postexercise ABI over baseline resting readings was calculated. The mean follow-up was 8 years (interquartile range, 4-11 years). RESULTS: During follow-up, 1321 patients (41.2%) died. After adjusting for clinical risk factors, lower resting ABI values (hazard ratio per 0.10 lower ABI, 1.08; 95% confidence interval [CI], 1.06-1.10), lower postexercise ABI values (hazard ratio per 0.10 lower ABI, 1.09; 95% CI, 1.08-1.11), and higher reductions of ABI values over baseline readings (hazard ratio per 10% lower ABI, 1.12; 95% CI, 1.09-1.14) were significantly associated with a higher incidence of mortality. In patients with a normal resting ABI (n = 789), a reduction of the postexercise ABI by 6% to 24%, 25% to 55%, and greater than 55% was associated with a 1.6-fold (95% CI, 1.2-2.2), 3.5-fold (95% CI, 2.4-5.0), and 4.8-fold (95% CI, 2.5-9.1) increased risk of mortality, respectively. CONCLUSIONS: Resting and postexercise ABI values are strong and independent predictors of mortality. A reduction of postexercise ABI over baseline readings can identify additional patients (who have normal ABI values at rest) at increased risk of subsequent mortality.

Ankle↗
PubMed2000

Bed rest in hospital for suspected impaired fetal growth.

BACKGROUND: Bed rest in hospital or at home is widely advised for many complications of pregnancy. The increased clinical supervision needs to be balanced with the risk of thrombosis, the stress on the pregnant women, as well as the costs to families and health services. OBJECTIVES: The objective of this review was to assess the effects of bed rest in hospital for women with suspected impaired fetal growth. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group trials register and the Cochrane Controlled Trials Register. Date of last search: December 1999. SELECTION CRITERIA: Randomised trials comparing a policy of bed rest in hospital with ambulatory management for women with suspected impaired fetal growth. DATA COLLECTION AND ANALYSIS: Trial quality was assessed. MAIN RESULTS: One study involving 107 women was included. Allocation of treatment was by odd or even birth date. There were differences in baseline fetal weights and birth weights, but these were not statistically significant (mean estimated fetal weight deviation at enrolment was -21.7% for the bed rest group and -20.7% for the ambulatory group; mean estimated birth weight was -19.7% for the bed rest group and -20.6% for the ambulatory group). No differences were detected between bed rest and ambulatory management for fetal growth parameters (relative risk 0.43, 95% confidence interval: 0.15 to 1. 27) and neonatal outcomes. REVIEWER'S CONCLUSIONS: There is not enough evidence to evaluate the use of a bed rest in hospital policy for women with suspected impaired fetal growth.

Bed Rest↗
PubMedDate not supplied

Effects of oral hydralazine on rest and exercise hemodynamics in patients with aortic or mitral regurgitation and left ventricular dysfunction.

The hemodynamic effects of afterload reduction were studied at rest and during two levels of upright exercise in patients with aortic or mitral regurgitation and left ventricular dysfunction. Eleven patients underwent invasive hemodynamic monitoring before and after 50-70 mg of oral hydralazine was given ever 6 h for 48 h. At rest, heart rate and mean arterial pressure after hydralazine were unchanged from control. During exercise, there was no significant change in heart rate, but mean arterial pressure fell significantly during the first level of exercise. Systemic vascular resistance was elevated before hydralazine and was significantly reduced after treatment at both exercise levels. After hydralazine, the resting oxygen consumption was significantly elevated at rest but was unchanged during exercise, the arteriovenous oxygen difference was significantly narrowed at both rest and exercise, and the pulmonary capillary wedge pressure was also significantly lower at both rest and exercise. In this select group of patients who are not candidates for surgical valve replacement, chronic afterload reduction with oral hydralazine may result in increased cardiac performance, decreased pulmonary congestion, reduced myocardial oxygen demands, and improvement in resting and/or exertional symptoms.

Administration, Oral↗
PubMed1994

Use of lower body negative pressure to assess changes in heart rate response to orthostatic-like stress during 17 weeks of bed rest.

This study examined the heart rate response to lower body negative pressure (LBNP) during 17 weeks of horizontal bed rest to estimate the development and duration of orthostatic instability elicited by this model for space flight. Based on data from Skylab, the authors hypothesized that orthostatic (LBNP) instability would appear during the first 3 to 4 weeks, and would then remain constant for the duration of bed rest. Heart rates of four healthy adult male subjects were monitored at rest and during LBNP for 1 week of ambulatory control, 17 weeks of horizontal bed rest, and 5 weeks of recovery. The LBNP protocol consisted of 10 minutes of control (atmospheric pressure) and 5 minutes each at 5, 10, 20, 30, 40, and 50 mm Hg decompression, followed by a 10-minute recovery period; this protocol was repeated weekly to document the progressive changes in heart rate response to LBNP. Lower body negative pressure was terminated early if symptoms compatible with the onset of syncope occurred. Throughout the study, heart rate was unchanged at 5, 10, and 20 mm Hg, but it increased at 30, 40, and 50 mm Hg LBNP. During the pre-bed rest period, peak heart rate was 97 +/- 10 beats/min (mean +/- SE), occurring at 50 mm Hg for all four subjects. After 3 days of bed rest, all monitored heart rate responses, including values after release of LBNP, were only slightly elevated (NS) above pre-bed rest level. Peak heart rate was 118 +/- 21 beats/min at 50 mm Hg decompression (NS; N = 3).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Blood volume responses of men and women to bed rest.

This paper reviews a series of studies that indicate that estrogens play an important role in blood volume regulation. The first study illustrates that the plasma volume (PV) of ambulatory women fluctuates during the menstrual cycle, increasing during periods of elevated estrogens. In the second study, it was shown that exogenous and endogenous elevations in blood estrogens attenuate the decrease in PV during bed rest. In the third study, the hypothesis was tested that women, who naturally have a higher blood estrogen content compared with men, will have a smaller loss of PV during bed rest. Ten men and ten women underwent a 13-day, 6 degrees head-down bed rest. Plasma volume and red cell mass (RCM) were measured before and after bed rest using 125I and 51Cr labeling, respectively. Before bed rest, the men and women had similar blood volume (BV) and PV (mL/kg body weight), but the women had a smaller (P < .01) RCM (22.2 +/- 0.9 versus 26.2 +/- 0.8 mL/kg, mean +/- SE). During bed rest, the decrease in RCM (mL/kg) was similar in men and women. However, the decrease in BV was greater in men (8.0 +/- 0.8 mL/kg versus 5.8 +/- 0.8 mL/kg), because of a greater reduction in PV (6.3 +/- 0.6 mL/kg versus 4.1 +/- 0.6 mL/kg). Because the decline in BV has been proposed to contribute to the cardiovascular deconditioning after bed rest, it is possible that women may experience less cardiac and circulatory strain on reambulation.

Adult↗
PubMed1988

A randomized cross-over study of enalapril in congestive heart failure: haemodynamic and hormonal effects during rest and exercise.

We performed a randomized double-blind placebo controlled cross-over study of enalapril in 16 patients with chronic congestive heart failure, to assess haemodynamic and hormonal effects at rest and on exercise. Acute effects were measured 4 h after enalapril 10 mg, and chronic effects after 6 weeks treatment with enalapril 10-20 mg per day. Exercise tolerance, assessed by the duration of a maximal bicycle ergometer test, was not altered by enalapril. Mean blood pressure was reduced after enalapril, at rest and on exercise, acutely by 7% and 8% respectively, and chronically by 14% and 16%. Systemic vascular resistance was reduced by 16% at rest both acutely (NS) and chronically (p less than 0.05). The resting pulmonary capillary wedge pressure was reduced by 28% with chronic treatment. In the acute study, total body oxygen consumption on exercise was 26% higher after enalapril. Chronically, resting oxygen consumption was reduced by 13% after enalapril, with mixed venous oxygen saturation increasing by 16%. In the acute study enalapril increased plasma renin activity at rest and on exercise by 181% and by 189%, and reduced aldosterone by 49% (NS) and 39% (p less than 0.05), and these effects were sustained after 6 weeks. Enalapril increased antidiuretic hormone concentrations at rest acutely by 73% (NS) and chronically by 34% (p less than 0.05) but not on exercise; the increase in the acute study correlated with plasma enalaprilat levels (r = 0.66, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Relative effects of the supine posture and of immersion on the renin aldosterone system at rest and during exercise.

The relative influences of the supine posture and of immersion on the renin-aldosterone system (RAS) were studied at rest and during moderate exercise in five healthy men. When supine, resting or immersion to the neck for 20 min in a thermoneutral environment both induced a decrease in plasma renin activity (PRA) when compared with the levels measured after 15 min sitting at rest (resting: -44%, p less than 0.05. Immersion: -45%, p less than 0.05). There was no significant difference in PRA decrease between the two situations. Aldosterone (ALDO) values were lower after supine rest or immersion than those observed after sitting at rest, but the difference was not significant. Two types of exercise at a constant relative work load (40-50% maximal oxygen uptake), namely cycling on an ergocycle in the supine position and free-style swimming, induced increases in PRA and ALDO when compared with the levels measured after 15 min rest when sitting (respectively, PRA = +35%, p less than 0.05, and +45%, p less than 0.05, ALDO = +32%, p less than 0.01 and +35%, p less than 0.05). Increases in PRA and ALDO did not differ between the two exercises. Thus inhibitory effects on RAS of change in external pressure are negligible during water immersion to the neck in the supine position and during swimming at moderate intensity.

Adult↗
PubMed1994

Enhanced slow caudad fluid shifts in orthostatic intolerance after 24-h bed-rest.

To evaluate mechanisms of late orthostatic intolerance, slow fluid shifts along the body axis were studied during deconditioning by 24-h bed-rest and during 13-min upright tilts before and after this manoeuvre. In 11 healthy male subjects the fluid volumes of a thorax and a calf segment (impedance plethysmography) as well as tissue thickness at the forehead and the tibia (miniature ultrasonic plethysmograph) were recorded. Cardiovascular performance was monitored by recording heart rate (electrocardiogram), brachial and finger arterial pressure (by the Riva Rocci method and by the Finapres technique) as well as stroke volume (by impedance cardiography). Bed-rest led to a cephalad fluid shift with a mean interstitial leg dehydration of 2.2 ml.100 ml-1 with no changes in body mass and plasma volume. No syncope during the tilt occurred before bed-rest, while after bed-rest 8 subjects fainted between min 2.1 and 9.0 of the tilt. Bed-rest resulted in an augmented initial heart rate response to tilting which was similar in all subjects. In later orthostasis, bed-rest caused two- to threefold faster caudad fluid shifts with higher calf filtration rates in fainters (prior to hypotension) than in nonfainters. Through bed-rest the estimated extravasation within 10 min into general lower body tissue spaces increased by 192 ml in (late) fainters as opposed to only 23 ml in nonfainters. It was concluded that contributing factors to orthostatic intolerance may be slow transcapillary fluid shifts which are easily underestimated and whose quantity and time course call for further investigation after various deconditioning manoeuvres. In particular, the postflight fluid shifts in astronauts who will have markedly dehydrated legs, may impose a circulatory stress which needs to be evaluated. In general, the filtration rate in relevant areas appears to be an integrative and easily determined parameter, reflecting hormonal and neurogenic vascular as well as local interstitial control of the Starling forces.

Adult↗
PubMed1993

Global and regional parameters of left ventricular performance in healthy subjects during rest and exercise assessed by radionuclide ventriculography.

The aim of our study was to analyze numerous global and regional parameters of left ventricular (LV) performance during rest and exercise, in the group of 14 healthy subjects, by quantitative gated equilibrium ventriculography in left anterior oblique view (45 degrees). The global LV parameters at rest vs. exercise in our study were: heart rate 68.9 +/- 18.4 vs. 137.5 +/- 38.6; systolic blood pressure (mmHg) 121.8 +/- 18.2 vs. 178.6 +/- 31.2; diastolic blood pressure (mmHg) 82.1 +/- 10.8 vs. 90.7 +/- 12.4; double product 8,368.6 +/- 2,308.8 vs. 24,589.3 +/- 8,357.8; global ejection fraction (%) 61.9 +/- 15.4 vs. 72.8 +/- 12.8, end-diastolic volume index (ml/m2) 82.5 +/- 23.2 vs. 96.9 +/- 27.8; end-systolic volume index (ml/m2) 31.8 +/- 19.8 vs. 26.9 +/- 15.4; stroke volume index (ml/m2) 50.6 +/- 17.6 vs. 70.0 +/- 22.6; peak emptying rate (EDV/s) 3.4 +/- 2.6 vs. 8.3 +/- 3.8 and peak filling rate (EDV/s) 3.6 +/- 2.6 vs. 9.6 +/- 3.8. A significant difference (p < 0.05) between rest and exercise was found for all parameters. The highest values of LV regional ejection fraction were found in anterolateral and posterolateral region, while the lowest values were observed in inferoseptal and inferior regions. During exercise a significant increase of regional ejection fraction was found in all regions. The highest percent of radius shortening during rest was in anterolateral and posterolateral regions, and lowest in inferoseptal and inferior regions. The same sequence was found during exercise, and the difference in percent of radius shortening, between rest and exercise was significant in all regions. The observed normal values of global and regional parameters of LV function during rest may serve as a contribution for referent values. Our results on regional ejection fraction and the percent of radius shortening in rest, and their change during exercise, offer the possibility of additional information in the investigation of cardiac patients by means of radionuclide ventriculography.

Exercise↗
PubMed2000

Comparative study of single-injection, single-acquisition 99mTc-MIBI gated SPET and stress-rest perfusion SPET for the evaluation of myocardial viability after bypass surgery in coronary artery disease.

In patients without previous myocardial infarction, the single-injection stress perfusion/rest function (SISPRF) approach using stress technetium-99m methoxyisobutylisonitrile (MIBI) gated single-photon emission tomography (SPET) can substitute for conventional stress-rest myocardial perfusion imaging for the assessment of myocardial viability. This study compared pre-operative single-injection, single-acquisition 99mTc-MIBI gated SPET and conventional stress-rest imaging for the prediction of myocardial viability in patients who underwent coronary artery bypass surgery (CABG). Rest thallium-201 SPET followed by stress 99mTc-MIBI gated SPET was performed in 20 patients [nine with previous myocardial infarction (MI) and 11 without previous MI). The study was performed before and 3 months after CABG, and viability assessment was validated by wall motion improvement after CABG. A four-point scoring system (0-3 for normal to absent tracer uptake) for 17 segments of the left ventricular myocardium was used for the assessment of stress and rest uptake. Wall motion, wall thickening and perfusion status were analysed by semi-quantitative visual assessment. On gated SPET, perfusion defect reversibility was considered present when a definite perfusion defect was observed and wall motion or thickening was normal or showed only a mild decrease. In patients with a previous MI, the left ventricular ejection fraction improved significantly after CABG (46% +/- 7% vs 42% +/- 11% before CABG, P < 0.05). In patients without previous MI, the ejection fraction improved significantly after CABG (50 +/- 12% vs 44% +/- 16% before CABG, P<0.05). In patients with previous MI, positive predictive values using the stress-rest reversibility and SISPRF approaches were 91% and 90%, respectively, and corresponding negative predictive values were 25% and 18%. In patients without previous MI, positive predictive values using the stress-rest and SISPRF approaches were 70% and 61%, respectively, and corresponding negative predictive values were 63% and 14%. It is concluded that SISPRF SPET study is of similar value to conventional stress-rest perfusion study in predicting wall motion improvement in patients with a previous MI, but that it is of limited value in predicting the myocardial viability of patients without previous MI, owing to a lower predictive value.

Aged↗
PubMed2004

Prevalence of ovarian adrenal rest tumours and polycystic ovaries in females with congenital adrenal hyperplasia: results of ultrasonography and MR imaging.

The aim of the investigation was to assess the prevalence of ovarian adrenal rest tumours and polycystic ovaries in female patients with congenital adrenal hyperplasia (CAH). Thirteen female CAH patients (median age 19.8 years, range 14.8-23.5 years) underwent transvaginal (n=6) or transabdominal (n=7) ultrasonography by a gynaecologist and MR imaging (n=13) of the ovaries (pre and post contrast-enhanced T1- and T2-weighted images). Ovarian adrenal rest tumours were defined as small hypoechoic and multifocal nodules on ultrasound and isointense lesions on T1- and hypointense on T2-weighted MR images (derived from characteristics of testicular adrenal rest tumours). Polycystic ovaries were defined as the presence of > or = 10 follicles arranged peripherally around or scattered throughout increased stroma. No ovarian adrenal rest tumours were found either on ultrasound, or by MR imaging. Polycystic ovaries were found in 2 of the 13 patients (15.4%), both with ultrasound and MR. No ovarian adrenal rest tumours were detected in these female CAH patients, which suggests that ovarian adrenal rest tumours in CAH females are rare. The prevalence of polycystic ovaries corresponded to that in the general population. From these results, we would suggest that routine ovarian imaging in CAH females is not indicated. However, when ovarian dysfunction is present, ovarian imaging is advised, first by ultrasonography, to detect ovarian adrenal rest tumours or polycystic ovaries.

Adolescent↗
PubMed2003

Gastrointestinal profile of symptomatic athletes at rest and during physical exercise.

Some athletes suffer from exercise-induced gastrointestinal (GI) disturbances. We developed a profile of GI parameters in 10 symptomatic and 10 asymptomatic athletes both at rest and during exercise. Exercise included 90 min of cycling and running at 70% of maximal power. We measured oesophageal motility, gastro-oesophageal reflux, gastric emptying, orocaecal transit time (OCTT), intestinal permeability and intestinal glucose absorption. During cycling the number and duration of refluxes were increased, whereas gastric emptying showed no differences between rest, cycling and running. The OCTT was increased in the running trial, compared to rest (P=0.005). Also, intestinal permeability was higher in the running trial, compared to rest (P=0.008). There were no differences in intestinal glucose absorption between rest and exercise. Compared with asymptomatic athletes the symptomatic subjects had a higher intestinal permeability (P=0.001), more reflux episodes (P=0.03) and a longer duration of reflux (P<0.05) during cycling. No differences were observed at rest. In conclusion, there is no difference in GI profile between symptomatic and asymptomatic athletes at rest. During exercise, symptomatic subjects have a longer OCTT and a higher intestinal permeability, which is more pronounced during running than during cycling.

Adult↗
PubMed2006

Strength, size and activation of knee extensors followed during 8 weeks of horizontal bed rest and the influence of a countermeasure.

Changes in the quadriceps femoris muscle with respect to anatomical cross sectional area (CSA), neural activation level and muscle strength were determined in 18 healthy men subjected to 8 weeks of horizontal bed rest (BR) with (n = 9) and without (n = 9) resistive vibration exercise (RVE). CSA of the knee extensor muscle group was measured with magnetic resonance imaging every 2 weeks during bed rest. In the control subjects (Ctrl), quadriceps femoris CSA decreased linearly over the 8 weeks of bed rest to -14.1 +/- 5.2% (P < 0.05). This reduction was significantly (P < 0.001) mitigated by the exercise paradigm (-3.5 +/- 4.2%; P < 0.05). Prior to and seven times during bed rest, maximal unilateral voluntary torque (MVT) values of the right leg were measured together with neural activation levels by means of a superimposed stimulation technique. For Ctrl, MVT decreased also linearly over time to -16.8 +/- 7.4% after 8 weeks of bed rest (P < 0.01), whereas the exercise paradigm fully maintained MVT during bed rest. In contrast to previous reports, the maximal voluntary activation remained unaltered for both groups throughout the study. For Ctrl, the absence of deterioration of the activation level might have been related to the repeated testing of muscle function during the bed rest. This notion was supported by the observation that for a subset of Ctrl subjects (n = 5) the MVT of the left leg, which was not tested during BR, was reduced by 20.5 +/- 10.1%, (P < 0.01) which was for those five subjects significantly (P < 0.05) more than the 11.1 +/- 9.2% (P < 0.01) reduction for the right, regularly tested leg.

Adult↗
PubMed1985

Ischemia at rest is independent of the extent of ventricular dysfunction and arrhythmias in patients with coronary artery disease.

To assess the relation between myocardial ischemia, ventricular arrhythmias (VA), and left ventricular (LV) dysfunction, we evaluated 74 patients with coronary artery disease (CAD) using radionuclide angiography (to determine the resting ejection fraction [EF]), resting thallium-201 scintigraphy (to ascertain the extent of resting ischemia), and 24-hour Holter monitoring (to assess VA). Thirty patients had resting ischemia, 26 had resting EF less than 30%, and 27 had repetitive VA. Patients with and without ischemia had similar EFs (36 +/- 14 vs 38 +/- 14, p = NS). Further, patients with and without repetitive forms of VA had a similar number of resting ischemic segments (1.1 +/- 1.7 vs 1.1 +/- 2.2, p = NS). Patients with EFs less than 30 had more VA than patients with EFs greater than or equal to 30 (Holter class 4.3 +/- 2.3 vs 3.0 +/- 1.8, p less than 0.01) but a similar extent of ischemia (1.4 +/- 2.2 vs 1.0 +/- 1.7, p = NS). Thus, while patients with lower EFs have more repetitive forms of VA, ischemia at rest is independent of VA and EF. These data suggest that prognostic stratification of patients with CAD for intervention studies should include a separate consideration of ischemia.

Arrhythmias, Cardiac↗
PubMed1989

Characterization of lymphocyte beta-adrenergic receptors at rest and during exercise in ambulatory patients with chronic congestive heart failure.

To investigate beta-adrenergic receptor dysfunction in congestive heart failure (CHF), the density of lymphocyte beta receptors and adenylate cyclase activity was measured at rest and at peak exercise in 30 patients with CHF and 7 age-matched control subjects. At rest, patients with CHF had reduced beta-receptor density (normals 33 +/- 2; CHF 21 +/- 2 fmol/mg protein; p less than 0.01) and isoproterenol-stimulated adenylate cyclase activity (normals 50 +/- 9; CHF 28 +/- 4 pmol/mg protein/min; p less than 0.05). Sodium fluoride-stimulated adenylate cyclase activity was also reduced (normals 98 +/- 17; CHF 48 +/- 12 pmol/mg protein/min; p less than 0.01). In the patients with CHF, there was no significant correlation between receptor density and peak exercise VO2, ejection fraction or resting plasma catecholamines. In the normal subjects, maximal exercise increased beta-receptor density by 100% (rest 33 +/- 2; exercise 67 +/- 7 fmol/mg protein) and isoproterenol-stimulated adenylate cyclase activity by 66% (rest 50 +/- 9; exercise 83 +/- 18 pmol/mg protein/min (both p less than 0.01]. In contrast, patients with CHF exhibited only a 58% increase in beta-receptor density (rest 20 +/- 3; exercise 32 +/- 6 fmol/mg protein; p less than 0.01) and no significant change in isoproterenol-stimulated adenylate cyclase activity (rest 27 +/- 5; exercise 24 +/- 5 pmol/mg protein/min).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenylyl Cyclases↗