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PubMed1980

Haemodynamics in juvenile hypertension at rest and during exercise.

In twenty-eight patients with juvenile hypertension haemodynamic examinations were made at rest and during exercise (600 kpm/min). The cardiac output was determined by the Fick method; venous blood was sampled from a floating catheter introduced into the pulmonary artery; the systemic pressure was measured directly in the brachial artery. In 57% of the juvenile hypertensives the resting cardiac index was higher than 4.5 l/min/m2. The increase was due to an increase in the stroke volume rather than in the heart rate. Of the patients 37.5% had increased cardiac output relatively to the oxygen uptake also during exercise; most of them were hyperkinetic already at rest. The resting systemic resistance was significantly elevated in patients whose resting systolic pressure was greater than 150 mmHg and/or diastolic pressure was greater than 90 mmHg, compared to controls; during exercise the values of systemic resistance lay within normal limits. The systemic pressure responded to the exercise by either a hypertonic or a normotonic reaction. In only 23% of subjects normotensive at rest a hypertonic response to exercise was found.

Adolescent↗

PubMed1980

Exercise testing in coronary artery disease with ST-segment abnormalities at rest.

In order to assess the diagnostic value of stress testing in patients with coronary artery disease (CAD) and ST abnormalities at rest, the results of a bicycle ergometer exercise, were compared in two groups of patients. Group 1 was composed of 58 CAD patients with normal resting ECG; group 2 was composed of 115 CAD subjects with abnormal ECG at rest. The latter group was then divided into three subgroups according to the absence (2a) or the presence (2b) of previous transmural myocardia infarction, or of previous transmural infarction with ST segment elevation at rest (3c). According to conventional exercise ECG criteria, the test was positive in 81% of group 1 and nearly in all the patients of group 2. In group 2 the prevalence of exercise-chest pain was constantly lower, particularly in subgroup 3c, in comparison with group 2. A greater prevalence of chest pain together with a greater severity of Gensini index were found in the subjects with positive exercise ECG in leads different from the impaired ones at rest. The diagnostic value of exercise ischemic changes location and of chest pain appearance, in patients with ST abnormalities at rest, is emphasized.

Angina Pectoris↗

PubMed1995

Fast stress and rest acquisitions for technetium-99m-sestamibi separate-day SPECT.

UNLABELLED: Abbreviated acquisition protocols were designed for stress and rest to decrease stress and rest SPECT image acquisition times but maintain the high count density of 99mTc-sestamibi separate-day cardiac images. METHODS: Scan findings were compared visually and quantitatively with standard SPECT for 12 rest and 32 stress patient studies. RESULTS: Of 29 stress defects detected by standard SPECT, 27 were present with the fast technique; of 8 resting SPECT defects, all were detected with fast SPECT. Two stress and no resting false-positive defects occurred with fast SPECT. Linear correlations (r) between standard and fast quantitative defect extent and severity were 0.76 and 0.86, respectively for stress SPECT, and 0.88 and 0.96 for rest SPECT. Stress fast defects were slightly less severe (p = 0.02) than those observed using standard acquisition. CONCLUSION: We conclude that these fast protocols for separate-day 99mTc-MIBI SPECT accurately detect and characterize perfusion defects and provide a means to improve patient tolerance and increase laboratory throughput.

Coronary Disease↗

PubMed1994

Effects of 10 and 20 days bed rest on leg muscle mass and strength in young subjects.

Sedentary voluntary students were exposed to 10 (n = 8) and 20 (n = 14) days bed rest to study effects of prolonged bed rest on isometric strength of knee extension and flexion, total leg strength, right hand grip and elbow flexion using different dynamometers. Further, muscle mass of right leg and arm was measured by dual energy X-ray absorptiometry, and cross sectional area of right thigh by X-ray computed tomography before and after bed rest and after 4 or 8 weeks of recovery. After 10 days bed rest, these variables tended to decrease except for the muscle mass of right arm which increased. After 20 days of bed rest, a similar trend was observed, but at a statistically significant level of p < 0.05. However, no correlation was observed between the decrease in knee extensor strength and cross sectional area of the thigh. Nor was a correlation observed between the sum total of isometric strength of the leg and the total muscle mass measured. The 24h urinary excretion of N2 and creatinine was not changed through the experiments. During recovery, the variables measured had reached the initial levels after 4 or 8 weeks. These changes were not affected by mild supine exercise training. The results suggest that isometric muscle strength was decreased in non-antigravity muscles as well as antigravity muscles by prolonged bed rest, but the rate of changes did not correlate to the corresponding changes in muscle mass. The decreases in maximum voluntary strength are probably not only due to the decrease in muscle mass but also due to reductions of neuromuscular function.

Absorptiometry, Photon↗

PubMedDate not supplied

Pelvic muscles during rest: responses to pelvic muscle exercise.

The purpose of the research was to study pelvic muscle changes in the resting phase between voluntary contractions (during pelvic muscle assessment) and in response to pelvic muscle exercise (PME) through secondary analysis of data. The sample consisted of healthy women (N = 38) aged 35 to 54. Analysis of variance showed a significant difference in resting pressure within each assessment (F = 2.92, p < .04). A significant difference in resting pressures within subjects was found (F = 3.54, p < .02). Within-subject variance suggests exercises performed without a warmup may result in incomplete relaxation prior to contraction. Significant change between baseline and Level 1 of the graded PME program suggests slow relaxation of untrained muscles. Increases in resting pressure at Levels 3 and 4 may be a more accurate reflection of muscle hypertrophy. The results of this research indicate that care should be taken in establishing the point from which changes during contractions are measured. It is recommended that the resting pressure be used. Exercise continued for more than 3 or 4 weeks accounts for nearly all strength gains and explains the increases in resting pressure at PME Levels 3 and 4.

Adult↗

PubMedDate not supplied

Physical and psychosocial side effects of antepartum hospital bed rest.

The purpose of this study was to describe the physical and psychosocial effects of antepartum hospital bed rest on pregnant women and to determine whether the symptoms exhibited differed from those exhibited by pregnant women not on bed rest. Women on complete bed rest (n = 10) had greater gastrocnemius muscle dysfunction, weight loss, and dysphoria than women on partial bed rest (n = 7) or no bed rest (n = 18). Separation from family was the greatest hospital stressor. Postpartum recovery from the side effects of bed rest was prolonged and included symptoms of muscular and cardiovascular deconditioning. The severity of side effects appeared to be directly related to the degree of severity restriction.

Activities of Daily Living↗

PubMed1995

[Hemodynamic assessment at rest and during dynamic physical exercise in young subjects with and without hypertensive parents].

The aim of this research was to identify any early cardiovascular changes that may be predictive of future hypertension in young subjects with family history of hypertension. The study was conducted on 25 offspring of hypertensive parents, mean age 17 years (22 with hypertension only in 1 parent and 3 with both hypertensive parents) and 20 offspring of both normotensive parents, matched by age. Subjects were divided into children (7-13 years) and young adults (19 years on). All subjects underwent three office blood pressure measurements with a mercury sphygmomanometer. On the third control, BoMed thoracic electrical bioimpedance at rest and during upright bicycle exercise was performed. Physical characteristics were similar in subjects matched by age in the two groups. Systolic blood pressure was similar in offspring of normotensives and hypertensives, both at rest and during exercise; diastolic blood pressure was greater in offspring of hypertensive parents at rest (73.1 +/- 10.5 vs 63.5 +/- 7.1 mmHg, p < 0.05), during the first minutes of exercise and during the recovery phase (p < 0.05). Moreover, at the third blood pressure measurement at rest, diastolic blood pressure decreased, with respect to the first measurement, only in children and young adult offspring of normotensive parents, while systolic blood pressure decreased in the two groups of child subjects. No differences in heart rate were observed, both at rest and during physical exercise, between offspring of normotensives and hypertensives. Left ventricular end-diastolic volume, stroke volume, ejection fraction, cardiac output and systemic vascular resistance at rest and their response to decubitus changes and exercise were normal and similar in offspring of normotensive and hypertensive parents both in children and young adults. In conclusion, a different behavior of diastolic blood pressure was found in offspring of hypertensive parents compared to that of normotensive parents, both in children and, to a higher degree, in young adults. This may be an expression of early vascular change in subjects with a genetic predisposition to hypertension.

Adolescent↗

PubMed1996

Reproducibility of measurements of regional resting and hyperemic myocardial blood flow assessed with PET.

UNLABELLED: PET with 13N-ammonia permits the noninvasive quantification of myocardial blood flow (MBF) in humans. The present study was done to assess the reproducibility of quantitative blood flow measurements at rest and during pharmacologically induced hyperemia in healthy individuals. METHODS: Thirty healthy volunteers (26 men, 4 women) were studied. Paired measurements of MBF at rest (n = 21), during adenosine (n = 15) and during dipyridamole (n = 7) were performed using a two-compartment model for 13N-ammonia PET. The mean difference between baseline and follow-up blood flow (% difference) was calculated to assess reproducibility. RESULTS: No significant difference was observed between resting blood flow at baseline or follow-up (15.8% +/- 15.8%; p = ns). Baseline and follow-up resting blood flow were linearly correlated (r = 0.63, p < 0.005). Normalization of resting blood flow to the rate pressure product improved the reproducibility significantly (15.8% +/- 15.8% versus 10.1% +/- 10.5%, p < 0.05). Baseline and follow-up hyperemic myocardial blood flow did not differ (11.8% +/- 9.4%; p = ns) and were linearly correlated (r = 0.69, p < 0.0005). CONCLUSION: MBF at rest can be measured reproducibly with 13N-ammonia PET. The individual response to pharmacologic stress appears to be relatively consistent. Thus, serial blood flow measurements with 13N-ammonia PET can be used to quantify the effect of various interventions on MBF and vasodilatory reserve.

Adenosine↗

PubMed1998

The effects of sublingual estradiol on left ventricular function at rest and exercise in postmenopausal women: an echocardiographic assessment.

OBJECTIVE: To evaluate the acute hemodynamic effects of 4 mg estradiol given sublingually. DESIGN: Rest and exercise echocardiographies were performed prior to estradiol administration. Then, another set of tests was done post-dose: rest examination at 1 h post-dose, isometric exercise at 65 min post-dose, and dynamic exercise at 100 min post-dose. RESULTS: The administration of 4 mg sublingual estradiol to 24 postmenopausal women (aged 48-58 years) was followed 60 min post-dose by a surge in mean estradiol serum levels (1759 +/- 704 pg/ml). At rest a slight drop in systolic and diastolic blood pressure was measured after estrogen ingestion: 132 +/- 24 mm Hg versus 127 +/- 21 mm Hg, p < 0.05; 83 +/- 11 mm Hg versus 78 +/- 10 mm Hg, p < 0.02. There were no changes in resting heart rate, double product, or vascular resistance. The left heart cavities became smaller: the left atrium diameter decreased from 33.7 +/- 4 mm to 32.3 +/- 4 mm, p < 0.01; the end-systolic diameter decreased from 24.9 +/- 3 mm to 23.6 +/- 4 mm, p < 0.01; the end-diastolic diameter decreased from 44.5 +/- 4 mm to 42.7 +/- 4 mm, p < 0.01. The peak aortic blood flow velocity fell from 120 +/- 19 cm/s to 116 +/- 22 cm/s (p < 0.05), and the flow velocity integral fell from 26.3 +/- 4 cm to 24.9 +/- 5 cm (p < 0.01); the cardiac output underwent a small change, with borderline significance: 7 +/- 2 L/min versus 6.7 +/- 2 L/min, p = 0.06. Only minor changes in the hemodynamic and echocardiographic parameters were recorded after estrogen for both isometric and dynamic exercises. Analyses were also made for two subgroups: 13 normotensive women were compared with 11 hypertensive women. The post-estrogen decreases in resting blood pressure and in peak blood velocity were observed only in the hypertensive subjects, whereas the changes in heart dimensions and in flow velocity integral were the same in both subgroups. CONCLUSIONS: Sublingual estradiol was associated with acute hemodynamic alterations mainly at rest but also after exercise.

Administration, Sublingual↗

PubMed1988

T helper cell-dependent induction of resting B cell differentiation need not require cognate cell interactions.

We have analyzed the role of cognate interaction with helper T cells (Th) in support of resting B cell differentiation to plaque formation. Co-culture of histoincompatible resting B cells and resting Th cells resulted in the induction of plaque-forming cells when dimeric but not monomeric fragments of anti-T cell receptor (TcR) antibody were added to culture. The efficiency of B cell activation was comparable to that supported by lipopolysaccharide and lectin-mediated Th-B cell conjugate formation. Further, if resting Th cells were preactivated with antigen and histocompatible antigen-presenting cells, the requirement for addition of anti-TcR to mixtures of histoincompatible Th and B cells was obviated. These results demonstrate that TcR-mediated Th recognition of major histoincompatibility complex class II/antigen composites on the resting B cell membrane does not provide obligate signals for B cell differentiation to plaque formation. We are left with two possibilities. Either the entire process of Th cell-dependent induction of resting B cell differentiation is mediated by soluble lymphokines or if Th-B cell contact is mandatory, it is mediated through nonpolymorphic cell surface determinants.

Animals↗

PubMed1992

The induction of resting B cell differentiation does not require T cell contact.

A T cell clone as well as immediately ex vivo CD4+ lymph node T cells are shown to support the differentiation of co-cultured resting B cells in the absence of T cell-B cell contact. Antibodies specific for class II products of the major histocompatibility complex inhibit the transactivation of resting but not activated B cells. This differential inhibition pattern indicates that the responses obtained from resting B cell populations are not due to their contamination with B cell blasts. Further, supernatants prepared from an activated T cell clone induce resting B cell differentiation. Two lines of evidence suggest that the activity contained in these supernatants can be attributed to interleukin (IL)-5. Activity is neutralized by monoclonal anti-IL-5; and both recombinant and affinity-purified IL-5 induce the differentiation of immediately ex vivo resting and activated B cells with comparable efficiency. Taken together, these results demonstrate that contact with T cells does not provide prerequisite signals for the induction of resting B cell differentiation.

Animals↗

PubMed1978

Regulation of protein synthesis in human diploid fibroblasts: reduced initiation efficiency in resting cultures.

The level of poly A+ RNA in growing cultures of human diploid fibroblasts is 1.8-fold times greater than in resting cultures. The level of functional ribosomes in growing cultures is 2.8 times that in resting cultures. Since transit times are similar in both types of cells, it can be concluded that the rate of protein synthesis in growing cultures is 2.8 times that in resting cultures. a reduced efficiency of mRNA translation at the level of initiation in resting cultures is proposed as a probable explanation for the fact that the decrease in protein synthesis rates is greater than the decrease in mRNA levels. This hypothesis is supported by the observations that: (a) poly A+ RNA is associated with smaller polysomes in resting than in growing cells, and (b) cycloheximide treatment of resting cells results in recruitment of nonpolysomal poly A+ RNA into polysomes and a shift of polysomal poly A+ RNA into larger polysomes.

Cell Cycle↗

PubMed2004

Acidic proteome of growing and resting Lactococcus lactis metabolizing maltose.

The acidic proteome of Lactococcus lactis grown anaerobically was compared for three different growth conditions: cells growing on maltose, resting cells metabolizing maltose, and cells growing on glucose. In maltose metabolizing cells several proteins were up-regulated compared with glucose metabolizing cells, however only some of the up-regulated proteins had apparent relation to maltose metabolism. Cells growing on maltose produced formate, acetate and ethanol in addition to lactate, whereas resting cells metabolizing maltose and cells growing on glucose produced only lactate. Increased levels of alcohol-acetaldehyde dehydrogenase (ADH) and phosphate acetyltransferase (PTA) in maltose-growing cells compared with glucose-growing cells coincided with formation of mixed acids in maltose-growing cells. The resting cells did not grow due to lack of an amino acid source and fermented maltose with lactate as the sole product, although ADH and PTA were present at high levels. The maltose consumption rate was approximately three times lower in resting cells than in exponentially growing cells. However, the enzyme levels in resting and growing cells metabolizing maltose were similar, which indicates that the difference in product formation in this case is due to regulation at the enzyme level. The levels of 30S ribosomal proteins S1 and S2 increased with increasing growth rate for resting cells metabolizing maltose, maltose-growing cells and glucose-growing cells. A modified form of HPr was synthesized under amino acid starvation. This is suggested to be due to alanine misincorporation for valine, which L. lactis is auxotrophic for. L. lactis conserves the protein profile to a high extent, even after prolonged amino acid starvation, so that the protein expression profile of the bacterium remains almost invariant.

Acetates↗

PubMed1997

Length of resting period between stimulation cycles modulates hemodynamic response to a motor stimulus.

The influence of different lengths of the pre-stimulation resting period on the magnitude of a hemodynamic response evoked by motor stimulation was examined in 10 subjects by means of near-infrared spectroscopy (NIRS). A motor stimulus was used which has been previously established as a model for functional activation studies with NIRS. Subjects performed a 20 s finger opposition task in the hand contralateral to NIRS probe localization over left sensorimotor area (C3', according to the 10-20 system). The duration of the pre-stimulation resting period was varied from 10s to 50s and response magnitude was assessed for each of the interstimulus intervals (10 s, 20 s, 30 s, 40 s and 50 s). Data analysis showed that response magnitude in oxygenated and deoxygenated haemoglobin concentration changed with different interstimulation intervals. Interestingly the greatest NIRS response was obtained with resting period 30 s prior to stimulation; shorter and longer resting periods resulted in smaller responses. The time course and the dependence of response magnitude on interstimulus interval differed between [oxy-Hb] and [deoxy-Hb] changes. For [oxy-Hb] the previously described fast initial increase ('overshoot') and the post-stimulation undershoot was more clearly seen with long prestimulation resting periods. Cytochromeoxidase oxygenation changes did not change significantly with different interstimulus intervals. We conclude that comparisons between different functional activation studies with techniques relying on stimulus evoked changes in cerebral hemodynamics must take into account not only the quality of the experimental paradigm and the length of the stimulation period, but also that the resting period between repetitive stimulations is important for response amplitude and its time course.

Brain↗

PubMed1992

Reliability of first-pass radionuclide determination of cardiac output in the upright position at rest and during exercise.

The reliability of non-invasive determination of cardiac output using first-pass radionuclide cardiography at rest and during exercise in the upright position was evaluated in 20 patients with coronary artery disease. Cardiac output values ranged from 2.97 to 5.99 l/min at rest and from 5.08 to 10.82 l/min during exercise. Cardiac output results obtained by the radionuclide method were compared with those derived from the thermodilution technique performed simultaneously. The mean difference between the two techniques was 0.02 l/min at rest and -0.34 l/min during exercise; the limits of agreement (mean +/- 1.96 SD) were -1.29 to 1.33 l/min and -1.97 to 1.29 l/min, respectively, indicating an acceptable level of agreement. A high reproducibility of the radionuclide technique was found, with a mean difference between determinations by two observers of 0.03 l/min at rest and 0.21 l/min during exercise, the corresponding limits of agreement being -0.75 to 0.81 l/min and -0.79 to 1.21 l/min, respectively. With the aid of a variance component analysis of two determinations by each of four observers, 95% confidence intervals of +/- 10% at rest and +/- 12% during exercise were computed for the radionuclide cardiac output measurements. The observer variation was most pronounced for the part of the cardiac output determination related to measurement of left ventricular equilibrium activity during exercise. First-pass radionuclide cardiography is a reliable method for determination of cardiac output in cardiac patients at rest and during exercise in the upright position.

Aged↗

PubMed1975

Inhibition by oxotremorine of acetylcholine resting release from guinea pig-ileum longitudinal muscle strips.

1. Longitudinal muscle strips of the guinea-pig ileum were incubated in Tyrode solution containing either DFP or physostigmine as cholinesterase inhibitor. After a 90 min preincubation period the acetylcholine resting release into the medium was determined. Acetylcholine was estimated by gas chromatography. 2. The resting release was 0.39 nmol/g times min irrespective of the cholinesterase inhibitor used. In the presence of hexamethonium, or after omission of external calcium, the resting release fell by 50 and 55 per cent, respectively. 3. Oxotremorine (10-5 and 10-4M) significantly inhibited the resting release of acetylcholine by 25 and 33 per cent, respectively. The inhibitory effect of oxotremorine was completely reversed by atropine (3 times 10-7 M). Oxotremorine did not reduce the spontaneous release of acetylcholine that occurred either in the presence of hexamethonium or in the absence of external calcium. 4. The acetylcholine content of the muscle strips was approximately doubled during the preincubation with a cholinesterase inhibitor. The subsequent incubation with oxotremorine did not lead to a further increase in the endogenous acetylcholine content. However, incubation of the muscle strips with oxotremorine in the absence of a cholinesterase inhibitor led to a rise in the endogenous acetycholine concentration. In in vivo experiments, oxotremorine also caused an increase in the acetylcholine content of the muscle strips. The possibility is discussed that the rise in the acetylcholine concentration following the administration of oxotremorine is a consequence of the decreased release. 5. It is concluded that oxotremorine inhibits the resting release of acetylcholine by activation of neuronal muscarinic receptors. The inhibitory effect of exotremorine is linked to that fraction of the acetylcholine resting release that is calcium-dependent and that arises from propagated activity in cholinergic neurones. The results are consistent with the hypothesis of a feed-back control of acetylcholine release mediated by inhibitory muscarinic receptors.

Acetylcholine↗

PubMed1977

[Light- and electronmicroscopic examinations on granulosa and theca of primordial-, primary-, secondary- and resting tertiary follicles of human ovaries (author's transl)].

Light- and electromicroscopic examinations were performed on granulosa and theca of primordial-, primary-, secondary- and resting tertiary follicles of human ovaries. These examinations were intended to clarify how far correlation exist between the structural components of the different tissue formations of the follicles and their determined functions. Remarkably many intraplasmatic filaments were found in the cytoplasm of granulosa cells of primordial-, primary- and secondary follicles. In the resting tertiary follicles the electronmicroscopy defines the majority of the follicle granulosa cells as proteinsynthetic active cells with abundant rough endoplasmatic reticulum. Most of the nuclei contain several nucleoli. An interesting finding compared with the granulosa cells of earlier developing stages of the follicle is the presence of single or grouped fat droplets in the cytoplasm, whereas metaplastic structures like filaments and/or microtubules are rare. The theca cells aroung the primordial-, primary- and secondary follicle were characterized by electromicroscopy as typical stroma cells. These cells of the resting tertiary follicles in the theca interna and externa show characteristic submicroscopic criteria of active steroidbiosynthesis. Their cytoplasm is especially rich of smooth endoplasmatic reticulum about from that there are tubular mitochondria and diffus fat droplets. Regarding the functional meaning of the different tissue formation of the follicles the existence of filamentous material in the membrana granulosa of primordial-, primary- and secondary follicles demonstrates an important finding. Apparently the presence of these metaplastic structures in the follicle granulosa cells play a role in the formal development of the zona pellucida and the Call-Exner-bodies. The structural organisation of the granulosa cells of resting tertiary follicles shows a high proteinsynthetic activity which plays a role in the metabolism of oocyte and the follicular fluid production. So far there are no definite submicroscopic criteria for steroidbiosynthesis. The structural differentiation of the normal stroma cells around primordial-, primary- and secondary follicles leads to definite submicroscopic steroidcells in the resting tertiary follicle. According to our results the process of the transformation of follicular granulosa cells in steroidbiosynthetic active cells in the resting tertiary follicle is not complete.

Adult↗

PubMed1983

Factors affecting the metabolism of resting rabbit papillary muscle.

The rate of resting heat production of 12 right ventricular rabbit papillary muscles was measured myothermically. Resting heat rate was measured at 4 temperatures (15, 20, 25 and 30 degrees C) in either 45% or 95% O2 while the muscle was passively stretched with various pre-loads. The metabolic substrate was pyruvate (10 mmol X 1(-1)). The mean resting heat rate, averaged across all treatment conditions, was 2.88 mW/g with no significant difference between the two oxygen concentrations. The calculated Q10 of the resting heat rate was surprisingly low--only about 1.4--but is shown to be in general agreement with literature values from whole heart oxygen consumption studies when the time-dependent decline is taken into account. Stretching the muscle beyond its rest length increased the rate of resting heat production. This response appeared unrelated to muscle diameter. The results are discussed in terms of the possible diffusion limitation of isolated papillary muscle preparations.

Animals↗