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Lactate metabolism in resting and contracting canine skeletal muscle with elevated lactate concentration.

This study was undertaken to quantitatively account for the metabolic disposal of lactate in skeletal muscle exposed to an elevated lactate concentration during rest and mild-intensity contractions. The gastrocnemius plantaris muscle group (GP) was isolated in situ in seven anesthetized dogs. In two experiments, the muscles were perfused with an artificial perfusate with a blood lactate concentration of ~9 mM while normal blood gas/pH status was maintained with [U-(14)C]lactate included to follow lactate metabolism. Lactate uptake and metabolic disposal were measured during two consecutive 40-min periods, during which the muscles rested or contracted at 1.25 Hz. Oxygen consumption averaged 10.1 +/- 2.0 micromol. 100 g(-1). min(-1) (2.26 +/- 0.45 ml. kg(-1). min(-1)) at rest and 143.3 +/- 16.2 micromol. 100 g(-1). min(-1) (32.1 +/- 3.63 ml. kg(-1). min(-1)) during contractions. Lactate uptake was positive during both conditions, increasing from 10.5 micromol. 100 g(-1). min(-1) at rest to 25.0 micromol. 100 g(-1). min(-1) during contractions. Oxidation and glycogen synthesis represented minor pathways for lactate disposal during rest at only 6 and 15%, respectively, of the [(14)C]lactate removed by the muscle. The majority of the [(14)C]lactate removed by the muscle at rest was recovered in the muscle extracts, suggesting that quiescent muscle serves as a site of passive storage for lactate carbon during high-lactate conditions. During contractions, oxidation was the dominant means for lactate disposal at >80% of the [(14)C]lactate removed by the muscle. These results suggest that oxidation is a limited means for lactate disposal in resting canine GP exposed to elevated lactate concentrations due to the muscle's low resting metabolic rate.

Animals↗

Left ventricular diastolic performance at rest and during exercise in patients with coronary artery disease. Assessment with first-pass radionuclide angiography.

We used first-pass radionuclide angiocardiography to assess filling fraction during the first third of diastole, peak filling rate and peak filling rate during the first third of diastole as indexes of left ventricular diastolic performance at rest and after upright bicycle exercise in 32 normal patients and 68 patients with coronary artery disease. The mean filling fraction was unchanged from rest to exercise in normal patients (47+/- 15% vs 46 +/- 13%; NS). Even in 49 coronary patients with normal (greater than or equal to 50%) ejection fraction at rest, filling fraction was less than that in normal patients at rest (35 +/- 11% vs 47 +/- 15%, p less than 0.001). Despite similar resting heart rates, patients with coronary disease had lower (p less than 0.001) peak filling rate and peak filling rate during the first third of diastole than normal patients. With exercise, filling fraction decreased (p less than 0.001) from the resting value in coronary patients. These data suggest that (1) indexes of diastolic performance can be noninvasively assessed at rest and during exercise using first-pass radionuclide angiocardiography, (2) abnormalities in early diastolic performance are often present at rest in patients with coronary artery disease despite normal systolic performance, and (3) exercise-induced ischemia results in increased early diastolic dysfunction in patients with coronary disease.

Adult↗

Improvement of resting myocardial asynergy with cessation of upright bicycle exercise.

Exercise generally aggravates ischemic myocardial dysfunction, presumably by increasing tissue oxygen demand out of proportion to the increase in supply. Nevertheless, resting left ventricular (LV) wall motion abnormalities can improve dramatically after upright exercise. To investigate this "paradoxical" phenomenon, we performed upright bicycle exercise equilibrium radionuclide ventriculography in 93 patients with angiographic coronary artery disease. Immediately after exercise, LV end-diastolic volume was similar to the resting level (1 +/- 22% of rest value), but end-systolic volume (ESV) was significantly below (p less than 0.05) that at rest (-11 +/- 32%) and LV ejection fraction increased significantly compared with rest (0.57 +/- 0.16 vs 0.51 +/- 0.13, p less than 0.05). Improvement in resting myocardial asynergy was frequent (115 of 330 abnormal segments), and was observed more commonly in patients without pathologic Q waves and in segments manifesting mild rather than severe asynergy. In 60 additional patients with resting asynergy who were also studied after nitroglycerin (NTG), there was 89% concordance of wall motion response in asynergic segments after exercise and NTG: 71 of 85 segments manifesting improvement with NTG also improved after exercise, and 157 of 172 segments without improvement with NTG also failed to improve after exercise. Despite the similar wall motion response, the mechanism of improvement is probably different from that produced by NTG. With NTG, preload (end-diastolic volume) and afterload (systolic blood pressure) were significantly lower than their resting control levels (p less than 0.05). These changes did not occur after exercise. Instead, an isolated, significant reduction in ESV was noted. These data support the hypothesis that catecholamine stimulation is responsible for paradoxical wall motion improvement after upright exercise.

Aged↗

Effects of nifedipine on systemic and regional oxygen transport and metabolism at rest and during exercise.

In a placebo-controlled, randomized, cross-over, double-blind study of 12 patients with stable exertional angina, we measured at rest and during bicycle exercise the effects of 20 mg of nifedipine administered sublingually on hemodynamics and systemic and regional oxygen extraction and metabolism. Nifedipine decreased systemic vascular resistance by 38% at rest (p less than .001) and by 28% during exercise (p less than .001). Cardiac output increased from 4.6 +/- 0.6 to 6.0 +/- 0.9 liters/min (p less than .001) at rest after nifedipine and from 10.6 +/- 3.7 to 11.8 +/- 3.4 liters/min (p less than .005) during exercise. After nifedipine, the arterial-mixed venous O2 content difference decreased from 4.7 +/- 0.6 to 3.5 +/- 0.5 ml/100 ml (p less than .001) at rest and from 10.5 +/- 1.7 to 8.8 +/- 1.6 ml/100 ml (p less than .001) during exercise. After nifedipine the arterial-iliac venous O2 content difference also decreased at rest, from 5.9 +/- 1.5 to 4.8 +/- 1.7 ml/100 ml (p = .06) but increased during exercise from 13.1 +/- 1.5 to 14.0 +/- 1.8 ml/100 ml (p less than .05). Oxygen consumption was not significantly altered at rest or during exercise. Nifedipine decreased mixed venous carbon dioxide tension (PCO2) during exercise from 53 +/- 3.5 to 50 +/- 4.0 mm Hg (p less than .05) but increased iliac venous PCO2 slightly from 61 +/- 4.6 to 63 +/- 5.2 mm Hg (p less than .01). Exercise pH was not significantly altered, but arterial lactate increased more after nifedipine (2.65 +/- 1.95 mmol/liter placebo, 3.54 +/- 2.74 mmol/liter nifedipine; p less than .05). Thus nifedipine produces similar changes in O2 extraction in mixed venous and iliac venous blood at rest but directionally opposite changes during exercise. The data support the hypothesis that nifedipine does not alter the distribution of cardiac output to the legs at rest, but during dynamic leg exercise reduces the redistribution of cardiac output to the legs. This probably results from the shunting of blood flow away from exercising muscles by the generalized vasodilatation of nifedipine.

Angina Pectoris↗

Prognostic value of invasive hemodynamic measurements at rest and during exercise in hypertensive men.

In 1994, we ascertained the outcome of 143 hypertensive men in whom invasive hemodynamic measurements were performed at rest and during graded bicycle exercise during the period 1972-1982 to assess (1) which of the hemodynamic components of blood pressure is associated with the incidence of cardiovascular events and total mortality, and (2) whether the hemodynamic response to dynamic exercise adds prognostic precision to the data at rest. During 2186 patient years of follow-up, 38 patients suffered at least one fatal or nonfatal cardiovascular event and 17 patients died. Cox regression analysis showed that systolic pressure and systemic vascular resistance measured at rest, during submaximal exercise (50 W), and at peak effort were significant (P < .01) predictors of the age-adjusted incidence of cardiovascular events and total mortality. However, exercise blood pressure did not significantly predict the incidence of cardiovascular events over and above pressure at rest; by contrast, exercise systemic vascular resistance added prognostic precision to vascular resistance at rest (P < .01). As for total mortality, systolic pressure and systemic vascular resistance at peak exercise carried prognostic information that was independent of the results at rest (P < .05); this was not the case for measurements during submaximal exercise. We conclude that the prognostic importance of blood pressure is related to systemic vascular resistance. The prognostic precision of exercise pressure, on top of pressure at rest, is limited. Exercise systemic vascular resistance, however, provides prognostic information beyond that available from measurements at rest, particularly for the incidence of cardiovascular events.

Adolescent↗

Increased resting energy expenditure in patients with end-stage renal disease.

BACKGROUND: Protein-calorie malnutrition is a significant problem for patients with end-stage renal disease. Increased resting energy expenditure may be an important contributing factor. We postulate that resting energy expen diture in the different stages of renal disease and treatments may be different. METHODS: Resting energy expenditure was measured using a whole-room indirect calorimeter (metabolic chamber) along with nutritional parameters and body composition after 12-hour fasting in 15 patients with advanced chronic renal failure patients, 15 patients on chronic hemodialysis, and 10 patients on peritoneal dialysis. Patients on hemodialysis were assessed on a non-dialysis day. A 2-day dietary recall was used to assess energy intake. RESULTS: Resting energy expenditure, adjusted for fat-free mass, was similar in patients on hemodialysis and peritoneal dialysis but significantly higher than in patients with chronic renal failure (p < .05). Resting energy expenditure in all patients were generally higher (10% to 20%) than predicted values using standard equations derived in normal and obese populations, whereas daily energy intake was less (26% to 34%) than energy expenditure for all groups, adjusted for light daily activity. CONCLUSIONS: End-stage renal disease patients displayed increases in resting energy expenditure over the predicted values derived using normal populations. Resting energy expenditure was significantly higher in patients receiving dialysis, regardless of the modality, than patients with chronic renal failure. Daily energy intake was substantially less than required in all patient groups studied, suggesting that patients with renal failure could develop protein-calorie malnutrition because of increased resting energy expenditure, which is exacerbated by dialysis.

Blood Proteins↗

Antepartum bed rest: maternal weight change and infant birth weight.

Despite lack of evidence for effectiveness, obstetricians in the United States prescribe antepartum bed rest for more than 700,000 women per year. However, in nonpregnant samples, bed rest treatment produces weight loss. This study assessed maternal weight change (gain) during antepartum hospitalization for bed rest treatment; compared appropriateness of infant birth weights for gestational age, race, and gender; and determined whether maternal weight change predicted infant birth weight. The convenience sample for this longitudinal study consisted of 141 women with high-risk pregnancies who were treated with hospital bed rest. Weekly rate of pregnancy weight change by body mass index was compared with Institute of Medicine recommendations for rate of pregnancy weight gain. Infant birth weight was compared with current US infant birth weights for matching gestational age, gender, and race. Weekly antepartum weight change was significantly lower than Institute of Medicine recommendations (P < 0.001). Infant birth weights were also significantly lower than the national mean when matched for each infant's gestational age, race, and gender (P < 0.001). Maternal weight change predicted infant birth weight (P = 0.05). Bed rest treatment is ineffective for improving pregnancy weight gain. Lower infant birth weights across all gestational ages suggest that maternal weight loss during bed rest may be associated with an increased risk of fetal growth restriction. A randomized trial comparing women with high-risk pregnancies who are ambulatory with those on bed rest is needed to determine whether bed rest treatment, underlying maternal-fetal disease, or both influence inadequate maternal weight gain and poor intrauterine growth.

Adult↗

The impact of rest duration on work intensity and RPE during interval training.

PURPOSE: To investigate the effect of rest duration on self-selected intensity, physiological responses, and RPE during a standardized, high-intensity interval training prescription. SUBJECTS: Nine well-trained male runners (VO(2max) 71 +/- 4 mL.kg(-1).min(-1)) performed three treadmill interval training sessions running at constant 5% incline. Six 4-min work bouts with either 1-, 2-, or 4-min recovery periods were performed in each session. Sessions were prescribed as "high-intensity" workouts with the goal being to achieve the highest possible average running speed for the work intervals. Subjects regulated their work and rest intensity based on these instructions. In a fourth interval session, subjects self-selected recovery time in response to a fixed intensity. RESULTS: Running velocity increased slightly (14.7 +/- 0.7 vs 14.4 +/- 0.8 km.h(-1), P = 0.02) when rest increased from 1 to 2 min, but showed no further increase with a 4-min rest (14.7 +/- 0.6 km.h(-1). Work VO(2) was slightly higher with a 2-min rest duration compared with 1 and 4 min (66.2 +/- 4.2 vs 65.1 +/- 4.2 and 64.9 +/- 4.7 mL.kg(-1).min(-1), P < 0.05). Peak blood lactate was similar (6.2 +/- 2.6, 6.8 +/- 2.9, 6.2 +/- 2.6 mmol.L(-1)) across conditions, whereas peak RPE was slightly lower during the 4-min rest condition (17.1 +/- 1.3, 17.7 +/- 1.5, 16.8 +/- 1.5, P < 0.05). With self-selected recovery time and no knowledge of elapsed time, the average rest duration was 118 +/- 23 s. CONCLUSIONS: Under self-paced conditions, varying rest duration in a range of 1 to 4 min had limited impact on performance during repeated 4-min high-intensity exercise bouts. Approximately 120 s of active recovery may provide an appropriate balance between intracellular restitution and maintenance of high VO(2) on-kinetics.

Adult↗

On the mechanisms of post-rest adaptation in the isolated electrically driven left atria of rats.

We studied the role of the resting period (1, 2, 4, 8, 16 min; n = 6-7), external Ca2+ (0.2, 0.4, 0.6 g/l; n + 5-6), stimulation frequency (1, 2, 3 Hz; n = 6), 4-aminopyridine (4-AP, 2 mM; n = 5); theophylline (1 mM; n = 6), ouabain (5 microM; n = 6), and verapamil (1 microM; n = 6) on post-rest adaptation in the isolated left atria of rats driven electrically by a 2x threshold intensity for 2 ms. Resting periods resulted in three-phasic adaptive changes in contractility during the post-rest stimulation before normalization: P1, hypercontractile phase, an initial twitch potentiation; P2, post-rest hypocontractile decay reached after 8 to 12 single twitches; and P3, a late reactive hypercontractile phase marked less than that of P1 and gradually declining to the pre-resting level. P1 and P2 were augmented along with increasing the resting period from 1 min to 16 min, whereas t1 (time between P1 and P2) shortened and P2 and t2 (time between P2 and P3) were not affected. P1 and P3 to become more apparent after shifting the stimulation frequency from 1 Hz to 3 Hz, accompanied by a shortening of t1 and t2 (p < 0.05) and an insignificant reversal of P2. An increase in Ca2+ concentration by 2- or 3-fold at 2 Hz reduced P1 was and antagonized P2, while leaving other parameters almost unaffected. The reduction of P1 by Ca2+ became more prominent at 3 Hz. Exposure to 4-AP depressed P1 and P3 at 1 Hz, which was reversed by increasing the stimulation frequency--P3 tended to diminish, whereas t1 and t2 were shortened. Theophylline reduced P1 antagonized P2, and shortened t1 and t2 significantly, and a combination of theophylline and 4-AP augmented the effects. Ouabain increased P1 and P2 in a frequency-dependent manner; prolonged t2 at 1 Hz, but shortened t2 at higher frequencies. Verapamil inhibition of Ca2+ channels augmented P1 and t1 and reduced P2 and P3, and the effects on all three parameters were augmented by combined 4-AP/verapamil. We concluded that the post-rest adaptive changes in contractility are a consequence of phasic changes in sarcoplasmic Ca2+ concentration and that such changes reflect an imbalance between the release from and uptake into the sarcoplasmic reticulum of Ca2+ and transsarcolemmal Ca2+ loss.

4-Aminopyridine↗

Effects of three-day bed rest on metabolic, hormonal and circulatory responses to an oral glucose load in endurance or strength trained athletes and untrained subjects.

The study was designed to find out (1) whether the effect of 3-day bed rest on blood glucose (BG) and plasma insulin (IRI) responses to glucose ingestion depends on preceding physical activity and (2) whether plasma adrenaline (A), noradrenaline (NA) and cardiovascular changes following a glucose load are modified by bed rest. Eleven sedentary students (22.5+/-0.3 yrs), 8 long distance runners (18.6+/-0.3 yrs) and 10 strength trained athletes (21.2+/-2.1 yrs) were examined before and after bed rest. Plasma IRI, BG, NA, A, heart rate (HR), and blood pressure (BP) were measured during 2 hrs following glucose (75 g) ingestion. The responses of BG and IRI to glucose load were calculated as incremental areas under the curves (auc). Both in athletes and untrained subjects bed rest markedly increased IRIauc, while BGauc was elevated only in sedentary subjects (p<0.05). The greatest increases in IRIauc and IRI/BG ratios were found in the endurance athletes. The data from all subjects (n = 29) revealed that the initial plasma NA and glucose-induced increases in NA and A were lowered after bed rest (p < 0.01). These effects were most pronounced in the endurance athletes. Bed rest did not influence HR or BP in any group. It is concluded that (1) the athletes have more adequate compensation for the bed-rest-induced decrement in insulin sensitivity than sedentary men; (2) three-day bed rest diminishes basal sympathetic activity and attenuates sympathoadrenal response to oral glucose; (3) endurance athletes have greater sympathetic inhibition than strength athletes or sedentary men.

Administration, Oral↗

[Meaning of rest in therapy for the depressive disorders-- role of the stress care ward].

The Meaning of Rest in Therapy for the Depressive Disorders-The Role of Stress Care Ward Rest is necessary in the therapy for the depressive disorders, even in the case that pharmcotherapy or psychological treatment seems to be effective. In this paper, the meaning of rest is examined, which is inclined to be underestimated. Especially, the meaning of admission in therapy for the depressive disorders is recognized and re-estimated. Rest is minimum environmental requirement for restoring spontaneous healing, and also is maximum therapeutic strategy for activating it. Systematic medical provision of rest is admission to stress-care ward, and it is given as environment in which stress-related sickness patients are able to be really rest. According to the study at the stress-care ward in the Siranui hospital in 2004, standard citizens were admitted with moderate depressive state, and around 90% patients were recovered after about three month therapy. Most important important therapeutic factors were supposed to be abundant stuff supply and team therapy. There are not enough hospital beds for the depressive disordered patients as adequate environment for rest. We hope radical medical policy change in this area in near future. We think that evidence based study is needed for examining effectiveness of rest and admission to stress-care ward as therapeutic strategy.

Adult↗

Effects of rest and exercise on cardiac blood volume determinations.

AIM: The purpose of this study was to investigate the changes in blood activity during rest, exercise and recovery, and to assess its influence on left ventricular (LV) volume determination using the count-based method requiring blood sampling. METHODS: Forty-four patients underwent rest-stress radionuclide ventriculography; Tc-99m-human serum albumin was used in 13 patients (Group I), red blood cells was labeled using Tc-99m in 17 patients (Group II) in vivo, and in 14 patients (Group Ill) by modified in vivo/in vitro method. LV volumes were determined by a count-based method using corrected count rate in blood samples obtained during rest, peak exercise and after recovery. RESULTS: In group I at stress, the blood activity decreased by 12.6 +/- 5.4%, p < 0.05, as compared to the rest level, and increased by 25.1 +/- 6.4%, p <0.001, and 12.8 +/- 4.5%, p < 0.05, above the resting level in group II and III, respectively. This had profound effects on LV volume determinations if only one rest blood aliquot was used: during exercise, the LV volumes significantly decreased by 22.1 +/- 9.6%, p < 0.05, in group I, whereas in groups II and III it was significantly overestimated by 32.1 +/- 10.3%, p < 0.001, and 10.7 +/- 6.4%, p < 0.05, respectively. The changes in blood activity between stress and recovery were not significantly different for any of the groups. CONCLUSION: The use of only a single blood sample as volume aliquot at rest in rest-stress studies leads to erroneous estimation of cardiac volumes due to significant changes in blood radioactivity during exercise and recovery.

Adult↗

Lengthy bed rest prescribed for acute low back pain: experience at three general medicine walk-in clinics.

Early gradual ambulation is currently recommended for patients with acute low back pain if results of neurologic examination are normal. Bed rest for up to 2 days is considered optimal. To assess management practices, we retrospectively reviewed the medical records of individuals with acute back pain treated at three independent general medicine walk-in clinics. Patients having an acute flare-up of chronic back pain were excluded. Bed rest was recommended at the initial visit for 171 patients who had normal findings on neurologic examination. The duration of recommended bed rest was recorded in 76 of these 171 patients' medical records (44%). The median duration of recommended bed rest was 5.5 days (range 1 to 14 days). Most patients (60/76 [79%]) were advised to rest in bed longer than 2 days. Even if all patients in whom duration of bed rest was not recorded had been told to rest in bed for 2 days or less, bed rest prescriptions would still have been too lengthy in 60 of these 171 patients (35%). This practice may prolong the recovery of patients with acute low back pain.

Adult↗

Comparison of rest and exercise thallium-201 kinetics in man and implications for quantitation.

To develop a technique for quantitative analysis of resting thallium scintigrams, an understanding of thallium kinetics at rest is required. This study evaluates in normal man the thallium distribution and washout rates of thallium at rest and compares these findings to similar data obtained during exercise. The thallium half-life in normal resting myocardium is significantly longer than after exercise, 10.2 +/- 1.4 hours versus 3.9 +/- 0.3 hours (P less than .01). Differences in resting thallium half-life exist between the anterior, 45 degrees left anterior oblique (LAO), and 70 degrees LAO views and are 11.4 +/- 1.0, 10.6 +/- 1.0, 8.8 +/- 0.7 hours, respectively (all significantly different from each other by ANOVA, P less than or equal to .01); these differences are related to the imaging sequence. After exercise, the thallium half-life also varies according to imaging sequence, but in the opposite direction; i.e., anterior, 45 degrees LAO, and 70 degrees LAO views are 3.6 +/- 0.1, 3.9 +/- 0.3, 4.2 +/- 0.3 hours, respectively (P less than or equal to .01). Since imaging sequence and time of acquisition at rest and exercise were similar, this finding may be related to earlier maximal uptake of thallium after exercise as compared to rest. There are also significant segmental differences in thallium half-life at rest in the 45 degrees LAO view (9.8 +/- 0.9, septal vs. 11.0 +/- 0.9, posterolateral, P less than .01) and 70 degrees LAO view (8.3 +/- 0.4, anteroseptal vs. 9.2 +/- 0.6, inferior, P less than or equal to .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Bed rest in pregnancy.

OBJECTIVE: To summarize existing data about the effectiveness of bed rest when used to improve various pregnancy outcomes and to determine how often bed rest is used and the cost associated with its use. DATA SOURCES: We used the MEDLINE data base to search for all English language papers evaluating the effectiveness of bed rest in pregnancy. We also reviewed a number of textbooks and the 1988 National Infant Mortality Survey. METHODS OF STUDY SELECTION: We reviewed these sources for recommendations about using bed rest in various obstetric conditions. We used the 1988 National Infant Mortality Survey to determine how often bed rest was used either to prevent or to treat various obstetric conditions and estimated the costs associated with its use. DATA EXTRACTION AND SYNTHESIS: Bed rest is used in nearly 20% of all pregnancies to prevent or treat a wide variety of conditions, including spontaneous abortion, preterm labor, fetal growth retardation, edema, chronic hypertension, and preeclampsia. There is little evidence of effectiveness. The estimated costs associated with bed rest, including hospitalization, lost wages, and lost domestic productivity, range from more than $250 million to billions of dollars per year. CONCLUSIONS: Bed rest is used extensively to treat a wide variety of pregnancy conditions, at substantial cost but with little proof of effectiveness. We recommend that because this intervention has failed the test of effectiveness, its use during pregnancy should be curtailed unless randomized trials demonstrate improvement in a specific outcome.

Bed Rest↗

Carbohydrate and lipid metabolism after 20 days of bed rest.

To test the hypothesis that physical inactivity affects carbohydrate and lipid metabolism, we studied the influence of 20 days bed rest in 14 young subjects (9 men and 5 women). There were no changes in body weight or estimated per cent body fat after 20 days bed rest. Total cholesterol, triglyceride, high density lipoprotein cholesterol, and apolipoprotein B levels did not change statistically during bed rest. But apolipoprotein AI levels were significantly lower during and immediately after bed rest compared with control values (p < 0.05). On the 3rd day of bed rest a decrease was found in high density lipoprotein-2 cholesterol (p < 0.05) and an increase in high density lipoprotein-3 cholesterol (p < 0.01) compared with control level. To evaluate the carbohydrate metabolism, each subject underwent a 75 g oral glucose tolerance test. The glucose concentrations in response to glucose ingestion did not change during bed rest, but insulin concentrations increased. The insulin-response curve to glucose ingestion tended to shift to the right during bed rest. From the 3rd day of bed rest an increase (p < 0.05) of total insulin and a decrease (p < 0.05) in blood glucose/insulin ratio were found during the glucose tolerance test which suggested a decrease in insulin sensitivity. These results suggested that physical inactivity impaired carbohydrate- and lipid metabolism.

Adult↗

[Value of stress-rest ECG gated SPECT one day protocol using 99mTc-MIBI].

A total of 110 patients suspected with CAD who had symptoms or ECG abnormalities were enrolled in the stress-rest ECG gated SPECT one day protocol using 99mTc-MIBI. All the patients underwent symptom-limited exercise testing and 250 MBq of MIBI was injected at peak exercise. Exercise perfusion SPECT images were reviewed by two trained doctors to classify into three groups; normal, equivocal and abnormal. Patients with normal stress image (n = 53) did not receive the resting study. On the other hand, those with equivocal (n = 20) and abnormal (n = 37) stress images performed resting study, including gated SPECT. Of 20 equivocal cases, 16 patients showed unchanged resting perfusion. All of these had normal wall motion. The remaining 4 patients showed improved resting perfusion, indicating presence of myocardial ischemia. Of 37 abnormal cases, 12 patients showed improved resting perfusion, whereas 25 patients showed unchanged resting perfusion. Cardiac events were more often observed in abnormal cases, especially those associated with myocardial ischemia, while good prognosis was obtained in normal cases. Values of this protocol are (1) Patients with normal stress images need no resting study. (2) All the procedure can be completed in one day. (3) Both cardiac function and perfusion can be obtained with gated SPECT. These data indicates that this protocol is valuable for screening patients suspected with CAD.

Coronary Circulation↗

Clinical validation of automatic quantitative defect size in rest technetium-99m-sestamibi myocardial perfusion SPECT.

UNLABELLED: We examined the relationships of automatic quantitative perfusion defect size and defect severity to rest left ventricular ejection fraction and semiquantitative visual sestamibi defect size in rest 99mTc-sestamibi SPECT in 40 consecutive patients with a history of myocardial infarction more than 30 days prior to testing. The purpose of this investigation was to validate the use of automatic quantitative rest sestamibi SPECT as a clinical measure of assessing relative infarction size. METHODS: All patients received 20-30 mCi of 99mTc-sestamibi followed by SPECT imaging. Quantitative defect analysis used previously developed resting normal limits and an automatic version of a commercially available quantitative program (CEqual). Semiquantitative visual defect interpretation used a 20 segment/scan and five-point scoring analysis. First-pass (FP) radionuclide ventriculography (RVG) and gated sestamibi perfusion SPECT were each performed in 31 patients. RESULTS: LVEF assessed by FP RVG was 37% +/- 15% (range 14%-62%) and 37% +/- 16% (range 12%-63%) by gated perfusion SPECT with high linear correlation (r = 0.96, n = 22) between the two methods. Myocardial perfusion defect size was 24% +/- 15% of LV (range 0%-50%) and defect severity was 1103 +/- 864 (range 0 to 2825) by automatic quantitative rest sestamibi. Perfusion defect size and defect severity both had close correlations with LVEF by FP RVG (r = -0.78, r = -0.86) and by gated perfusion SPECT (r = -0.75, r = -0.79). High linear correlations were observed between quantitative defect size and summed visual score of segments with score > or = 2 (r = 0.82) and the number of visually abnormal segments (r = 0.77), as well as between defect severity and visual summed rest score (r = 0.86) and the number of visually abnormal segments (r = 0.76). CONCLUSION: Quantitation of rest sestamibi SPECT defect extent and severity using automatic CEqual correlates well with rest LVEF and with semiquantitative expert visual analysis. Results of this study define a strong relationship between measurements of 99mTc-sestamibi perfusion defect as measured by an automatic software program and global left ventricular function. The automatic quantitative program appears to be a useful measure of assessing infarct size in patients with remote myocardial infarction.

Adult↗