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 433 records · Page 24Linked to original sources
PubMedDate not supplied

Cumulative dose-response curves for gallamine: effect of altered resting thumb tension and mode of stimulation.

Neuromuscular blockade studies often use the thumb adductor twitch response to ulna nerve stimulation. Two factors that may influence the results are the resting muscle tension (initial fiber length) and the pattern of the stimulus wave form. This study was undertaken to improve understanding of the effect of these factors and lead to better controlled study conditions and more consistent data. During nitrous oxide-barbiturate-narcotic anesthesia in 10 normal adult patients, as the resting thumb tension was increased from 50 to 200 g, the evoked thumb adductor twitch response (Grass stimulator, 0.25 Hz) was augmented by 28%. There was only a 2.5% increase in the evoked (developed) tension when the resting tension was further increased from 200 to 300 g. Developed tension at 50 g was significantly (p less than 0.001) less than at the other resting tensions. The developed tension at 100 g was also significantly (p less than 0.05) less than at resting tensions of 200 or 300 g. Cumulative dose-response curves for gallamine in nine patients were not significantly altered by increasing resting tension from 50 to 200 g. Biphasic (Block-Aide monitor) or single square wave (Grass stimulator) stimuli wave forms in nine normal adult patients yielded gallamine dose-response curves that were not statistically different. The muscle response to biphasic stimulation during a non-depolarizing blockade was not affected by the average muscle refractory period. Because of the significantly lower developed tension at resting tension settings of 50 to 100 g, a practical consideration during neuromuscular function studies would be to have the resting thumb tension adjusted and rechecked for each patient and kept within the 200-300-g range to ensure maximum uniform developed tension. The type of stimulus wave form selected will not affect results as long as it is used consistently throughout the study.

Adjuvants, Anesthesia↗
PubMed2006

Depletion of resting zone chondrocytes during growth plate senescence.

With age, the growth plate undergoes senescent changes that cause linear bone growth to slow and finally cease. Based on previous indirect evidence, we hypothesized that this senescent decline occurs because growth plate stem-like cells, located in the resting zone, have a finite proliferative capacity that is gradually depleted. Consistent with this hypothesis, we found that the proliferation rate in rabbit resting zone chondrocytes (assessed by continuous 5-bromo-2'-deoxy-uridine labeling) decreases with age, as does the number of resting zone chondrocytes per area of growth plate. Glucocorticoid excess slows growth plate senescence. To explain this effect, we hypothesized that glucocorticoid inhibits resting zone chondrocyte proliferation, thus conserving their proliferative capacity. Consistent with this hypothesis, we found that dexamethasone treatment decreased the proliferation rate of rabbit resting zone chondrocytes and slowed the numerical depletion of these cells. Estrogen is known to accelerate growth plate senescence. However, we found that estradiol cypionate treatment slowed resting zone chondrocyte proliferation. Our findings support the hypotheses that growth plate senescence is caused by qualitative and quantitative depletion of stem-like cells in the resting zone and that growth-inhibiting conditions, such as glucocorticoid excess, slow senescence by slowing resting zone chondrocyte proliferation and slowing the numerical depletion of these cells, thereby conserving the proliferative capacity of the growth plate. We speculate that estrogen might accelerate senescence by a proliferation-independent mechanism, or by increasing the loss of proliferative capacity per cell cycle.

Aging↗
PubMed1998

Resting of pigs and hot-fat trimming and accelerated chilling of carcasses to improve pork quality.

Market pigs (n = 120) were rested 0, 1, 2, or 3 h before slaughter. One carcass side was hot-fat trimmed (HFT) immediately after dressing, and the other was not fat trimmed (NFT). Sides received conventional chilling (CC) or accelerated chilling (AC) in a freezer at -32 degrees C for 100 min. Skin temperatures of live pigs decreased 5 degrees C during 3 h of rest, and resting reduced muscle temperature at .5 and 1.5 h postmortem. Early postmortem muscle pH was .3 higher if pigs were rested up to 2 h if CC was used (P < .01). Resting pigs 2 h decreased loin purge about 1% and increased cured ham yields 6% over those not rested. The AC carcasses had about .15 higher muscle pH from 4.5 to 24 h postmortem than CC carcasses (P < .03). The AC improved loin quality about 15% and lowered L values of loins and hams about 4% (P < .04). The AC substantially reduced the incidence of unacceptable quality in loins and hams, with the most effect on hams, and slightly toughened loin muscles but not cured ham muscles. Resting of pigs and AC of carcasses gave superior color of loin chops at d 0 of retail display and lowered L values during display. The HFT process improved ham quality scores about 8% but not loin scores. Resting pigs for 2 h, AC, and HFT in concert or separately are effective means of improving pork quality; AC had by far the greatest effect.

Animals↗
PubMed1999

[The effect of partial refeeding on serum levels of leptin and resting energy expenditure in female patients with anorexia nervosa].

BACKGROUND: Serum leptin levels and resting energy expenditure are significantly decreased in patients with anorexia nervosa compared to healthy subjects. Partial realimentation of patients with anorexia nervosa increases both these parameters. However, there so far are no data concerning the relationship of serum leptin levels and resting energy expenditure in patients with anorexia nervosa. The aim of our study was to follow the relationship of serum leptin levels and resting energy expenditure in patients with anorexia nervosa before and after refeeding. METHODS AND RESULTS: It was found that serum leptin levels in patients with anorexia nervosa both before and after partial realimentation were significantly lower compared to healthy subjects (0.86 +/- 0.9 ng.ml-1 and 1.77 +/- 1.9 ng.ml-1 vs 6.85 +/- 3.0 ng.ml-1, p < 0.05). The total resting energy expenditure in patients with anorexia nervosa both before and after realimentation were significantly lower than in the control group (4973 +/- 979 and 5263 +/- 899 vs 6401 +/- 827 kJ/day, p < 0.05). When expressed per body weight the resting energy expenditure in patients with anorexia nervosa was significantly higher in comparison with the control group (122.3 +/- 20.6 and 121.5 +/- 14.2 vs 104.2 +/- 14.6 kJ/day, p < 0.05). The differences in resting energy expenditure in patients with anorexia nervosa before and after refeeding did not reach statistical significance. The body mass and the body fat content increased significantly after realimentation index (14.5 +/- 1.4 vs 15.6 +/- 1.5 kg.(m2)-1 and 14.9 +/- 3.4 vs 16.6 +/- 3.7, p < 0.05) but remained still below of those of control group (BMI 22.3 +/- 2.7, body fat content 26.9 +/- 4.2). CONCLUSIONS: Our study confirmed the reduced serum leptin levels and the total resting energy expenditure in patients with anorexia nervosa compared to healthy age-matched subjects. No statistically significant relationships were found between serum leptin levels and resting energy expenditure either in healthy subjects or in patients with anorexia nervosa before or after partial realimentation respectively.

Adolescent↗
PubMed2000

[Relationship between exercise capacity and left ventricular function at rest in patients with heart insufficiency: radionuclide continuous monitoring of left ventricular function].

PURPOSE: To evaluate the relationship of systolic and diastolic function at rest to exercise capacity. MATERIAL AND METHODS: Seventeen patients with ischemic heart failure were included in the study. Ambulatory left ventricular monitoring at rest and during upright exercise with combined analysis of pulmonary gas exchange was performed. Ejection fraction, end-diastolic volume, end-systolic volume, stroke volume, cardiac output, and peak filling rate were measured. RESULTS: Significant positive correlations were found between rest ejection fraction and peak oxygen consumption (r = .60, p < .01), peak cardiac output (r = .77, p < .0001), peak stroke volume (r = .67, p < .005), and peak ejection fraction (r = .69, p < .005). On the other hand, peak filling rate at rest showed a significant inverse correlation with peak end-diastolic (r = -.48, p < .05) and end-systolic (r = -.66, p < .005) volumes. The patients were then subgrouped into two groups according to their rest ejection fraction (lower or higher than 40%). In the group with ejection fraction less than 40% a significant correlation was observed between rest ejection fraction and both peak stroke volume (r = .66, p < .05) and peak ejection fraction (r = .69, p < .05). In the same group of patients an inverse correlation was found between peak filling rate and both end-diastolic (r = -0.65, p < .05) and end-systolic (r = -.82, p < .005) volumes. CONCLUSIONS: The results of the present study suggest that exercise capacity is related to left ventricular function at rest and that rest diastolic function might be a determinant of left ventricular function during exercise in patients with heart failure.

Exercise Tolerance↗
PubMed2000

Influenza vaccination coverage in Canterbury rest homes.

AIMS: First, to investigate the effect on Canterbury rest home residents of national policy making influenza vaccination free for those aged 65 years and over. Second, to assess rest home staff influenza vaccination coverage. METHODS: A comparison of influenza vaccination coverage in Canterbury rest home residents during 1996 and 1997 was conducted. Subgroups of rest homes were formed in 1997 to minimise the bias introduced through conducting a coverage survey in 1996. Staff vaccination coverage was also assessed in 1997. RESULTS: Influenza vaccination coverage of Canterbury rest home residents was 74% in 1996 and 76% in 1997. Staff vaccination coverage was 21% in 1997. Significantly more staff were vaccinated in rest homes that offered free influenza vaccination to their staff. CONCLUSIONS: The free influenza vaccination policy had no measurable impact on Canterbury rest home residents' vaccination coverage. This may be due to a ceiling effect of previously high coverage. Coverage was low amongst rest home staff. Providing the vaccination free of charge might improve staff coverage.

Aged↗
PubMedDate not supplied

Differential human immunodeficiency virus-suppressive activity of reverse transcription inhibitors in resting and activated peripheral blood lymphocytes: implications for therapy.

OBJECTIVES: Because recent evidence indicates that human immunodeficiency virus type 1 (HIV-1) propagates in resting T lymphocytes in vivo, we wanted to evaluate the antiviral effects exerted by currently used nucleoside (NRTI) and non-nucleoside analog reverse transcription inhibitors in resting lymphocytes, and compare those effects to the ones obtained in activated lymphocytes. METHODS: Tissue culture antiviral assays in which target cells are lymphocytes present in a resting or activated state. Virus replication was measured by a reverse transcription (RT) assay. Cell viability was evaluated using a commercial 3-(4k5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. RESULTS: In vitro results obtained with concentrations of zidovudine and stavudine equivalent to drug levels found in plasma, showed more than 99% HIV-1 inhibition in activated lymphocytes but less than 50% virus inhibition in resting lymphocytes. Conversely, plasma levels of didanosine-inhibited HIV-1 by approximately 50% and 98% in activated and resting lymphocytes, respectively. Plasma level concentration of zalcitabine, lamivudine, and abacavir inhibited viral replication by more than 90% in both resting and activated cells. CONCLUSIONS: These data demonstrate that specific NRTI antiretroviral agents have different activity against HIV RT, depending on the state of cell cycle of the infected cell. We suggest that the replication of HIV-1 in resting lymphocytes should be taken into account in the design of future clinical trials, as well as treatment antiretroviral regimens. Selection of combination RTIs so that they provide antiretroviral activity in both resting and activated lymphocytes may be a way to minimize treatment failure and the emergence of drug-resistant variants.

Anti-HIV Agents↗
PubMed1976

[Pulmonary artery pressure and left ventricular late diastolic pressure in rest and during dynamic load. Comparative studies on pressure transmission in the pulmonary circulation during simultaneous determination].

Left ventricular enddiastolic pressure (LVEDP), mean pulmonary artery pressure (PAPM) and enddiastolic pulmonary artery pressure (PADP) were simultaneously recorded in 19 subjects with normal left ventricular (LV) function, and in 109 patients with LV-dysfunction, 83 of whom were also studied during exercise. Patients with valvular heart disease or atrial fibrillation were excluded from this study. LVEDP and mean pulmonary capillary wedge (PCW) pressure were simultaneously recorded in 81 patients at rest, andin 16 patients also during exercise; the LV diastolic pressure prior to atrial contraction (LVPpreA) could accurately be identified in 45 patients at rest and in 23 patients with exercise. In contrast to the widely accepted opinion of others, the PADP (mean 8.2 +/- 2.2 mm Hg at rest and 12.3 +/- 3.4 mm Hg with exercise) showed a close approximation of LVEDP (10.0 +/- mm Hg at rest and 16.2 +/- 3.5 mm Hg with exercise) only in normal subjects at rest (p less than 0.05 and p less than 0.01 respectively). In patients with LV dysfunction there was no significant difference between PADP (11.7 +/- 4.5 mm Hg and 23.0 +/- 8.9 mm Hg), PCW (11.6 +/- 5.1 mm Hg and 24.1 +/- 11.9 mm Hg) and LVPpreA (12.5 +/- 5.5 and 21.5 +/- 7.7 mm Hg) at rest and during exercise. LVEDP could be estimated with sufficient accuracy only from the PAPM (18.9 +/- 6.5 and 35.7 +/- 10.8 mm Hg). The increase in LVEDP (14.7 +/- 7.7 mm Hg) with exercise was not significantly different from the increase in PAPM (16.8 +/- 7.1 mm Hg). There were highly significant correlations (p less than 0.001) between LVEDP and PADP (r = 0.85) as well as PAPM (r = 0.86) at rest and during exercise with the regressionline being closest to the line of identity for LVEDP and PAPM. The pressure gradient between LVEDP and PADP (LVEDP - PADP = 6.3 mm Hg with exercise) equaled the pressure increase in LV by atrial contraction (LVEDP - LVPpreA = 6.3 and 13.3 mm Hg). The pressure difference between PADP or PAPM and LVEDP remained constant despite marked variation of other hemodynamic parameters, e.g. stroke volume index (SVI), heart rate (HR) and cardiac index(CI). These data suggest that an elevated LVEDP is caused mainly by an augmented atrial contraction in patients with LV dysfunction at rest and with exercise. This mechanism precludes an enddiastolic pressure equilibrium between pulmonary artery and left ventricel. PAPM allows the best estimation of LVEDP independent from other hemodynamic variables.

Adult↗
PubMed1992

Effects of 1-week head-down tilt bed rest on bone formation and the calcium endocrine system.

To understand the potential early responses of human bone and the calcium endocrine system to spaceflight, we studied 8 healthy men, aged 35-44 years before, during, and after bed rest in a -6 degrees head-down tilt model for microgravity. Based on a novel single-dose labeling schedule, average rates of bone formation in the iliac crest were reduced in 6, unchanged in 1, and increased in 1 following the bed rest period. The decrease was greatest for subjects whose daily walking miles were highest (r = -0.762, p less than 0.05, n = 7). Before a measurable increase in ionized serum calcium the sixth bed rest day, there was increased excretion of urinary calcium and sodium, evident the first 2 bed-rest days and parallel for the entire week (r = 0.92, p less than 0.001). Reduced excretion of phosphorus and 3', 5' cyclic adenosine monophosphate on the first and second bed rest days was followed by an increase in serum phosphorus by the sixth bed rest day. Depressed serum concentrations of parathyroid hormone and 1,25-dihydroxyvitamin D were manifest by the sixth and seventh bed rest days. The similarity of the response of bone and the calcium endocrine system of healthy men after only 7 days to results of longer term bed rest studies emphasizes the responsiveness of the adult human skeleton to biomechanical stimuli induced by changes in activity and/or position.

Adult↗
PubMed1990

Serum digoxin concentration: increase after rest in different body positions.

If outpatients are allowed to rest in the supine position before their blood is sampled, serum digoxin increases. In a recent study, the serum digoxin concentration after 2-h standardized supine rest correlated better with the clinical status of patients than the value before rest. In the present study, 21 outpatients were studied on 2 consecutive days, approximately 24 h after the latest dose of digoxin. Blood samples for the assay of serum digoxin were taken on arrival at the department and after 1.5- and 2-h rest either supine or sitting (random order). The increases after 1.5-h rest were 12% (0-25%; p less than 0.001) and 12% (-3-47%; p less than 0.001), supine and sitting, respectively. The respective increases after 2-h rest were 14% (-11-32%; p less than 0.001) and 16% (0-74%; p less than 0.001). There were no statistically significant differences between the increases in serum digoxin concentration after supine and sitting rest. These results make it possible to recommend standardized rest in the sitting position (1.5-2 h) for outpatients before blood samples are collected when reliable serum digoxin analyses are of importance.

Aged↗
PubMed1991

Mechanisms underlying post-rest potentiation in isolated left rat atria.

In the isolated rat left atria the influence of rest intervals on the force developed by the first post rest beat (PRB) was studied. Under control conditions the force developed by the PRB increased (respect to previous steady state at 0.5 Hz) with the increase of the rest interval until 20 sec of pause and decreased with longer intervals. In the presence of caffeine (1 or 4 mM plus high [Ca]0) there was a monotonous fall of the PRB as a function of the rest interval. When extracellular calcium was replaced by Sr the tension developed by PRB vs. rest interval curve rose with a slope lower than the control one and reached the peak at 60 sec. At saturation levels of [Ca]0 the PRB tension development did not vary up to 20 sec pause but the decreasing phase observed after 20 sec of rest interval was still present. At 0.5 mM [Ca]0 the response was similar to control curve. The results in the presence of caffeine and strontium suggest that, in rat atria, the rest potentiation appears to be dependent on the release of calcium from intracellular stores (sarcoplasmic reticulum). This is consistent with the hypothesis proposing that longer resting periods provide a longer interval for the transfer of Ca from uptake to release sites in the sarcoplasmic reticulum.

Analysis of Variance↗
PubMed1989

[Effect of intracoronary and intravenous administration of propranolol on coronary vasomotility at rest and during exercise].

The effect of intracoronary and intravenous propranolol on coronary vasomotion was evaluated in 30 patients with coronary artery disease. Luminal area of a normal and a stenotic coronary segment was determined at rest, during supine bicycle exercise and 5 min after 1.6 mg sublingual nitroglycerin administered at the end of the exercise test using biplane quantitative coronary arteriography. Patients were divided into 3 groups: Group I (n = 12) served as control Group II consisted of 10 patients with intracoronary administration of 1 mg propranolol and Group III of 8 patients with intravenous administration of 0.1 mg/kg propranolol prior to the exercise test. In the control Group there was coronary vasodilation (+23%, p less than 0.01) of the normal and coronary vasoconstriction (-29%, p less than 0.001) of the stenotic vessel segment during bicycle exercise. After sublingual administration of 1.6 mg nitroglycerin there was vasodilation of both normal (+40%, p less than 0.001 vs rest) and stenotic (+12%, NS vs rest) segments. In Group II intracoronary propranolol was not accompanied by a change in coronary area but both normal (+13%, p less than 0.05) and stenotic (+22%, p less than 0.05) segments showed coronary vasodilation during bicycle exercise. After sublingual nitroglycerin there was further vasodilation of both normal (+31%, p less than 0.001 vs rest) and stenotic (+45%, p less than 0.01 vs rest) arteries. In Group III intravenous administration of propranolol was associated with a decrease in coronary luminal area of both normal (-24%, p less than 0.001) and stenotic (-41%, p less than 0.001) segments. During dynamic exercise there was coronary vasodilation of both segments when compared to the data after intravenous injection of propranolol but there was no change in luminal area (normal vessel-2%, NS vs rest; stenotic vessel-3%, NS vs rest) when compared to the resting data. After sublingual administration of 1.6 mg nitroglycerin both normal (+21%, p less than 0.001) and stenotic (+46%, p less than 0.001) segments showed coronary vasodilation. It is concluded that supine bicycle exercise in patients with coronary artery disease is associated with vasodilation of the normal and vasoconstriction of the stenotic coronary arteries. Intravenous administration of propranolol is followed by coronary vasoconstriction of both normal and stenotic coronary arteries probably due to secondary mechanisms (reduction in heart rate and contractility) because it is not observed after intracoronary injection of propranolol and it is overridden by bicycle exercise and sublingual nitroglycerin.

Adult↗
PubMed1985

Antigen presentation by EBV-B cells to resting and activated T cells: role of interleukin 1.

We have previously demonstrated that Epstein Barr virus-transformed human B lymphocytes (EBV-B cells) present antigen to activated T cells (lines and clones) in a MHC-restricted manner. In the present study, using EBV-nonimmune donors, we demonstrate that EBV-B cells are unable to trigger tetanus toxoid (TT) antigen-specific proliferation in autologous highly purified resting T cells. EBV-B cells from these same individuals were able to present TT to autologous TT-specific activated T cell blasts (Tbl). The inability of EBV-B cells to present TT to resting T cells was not caused by defective antigen processing by EBV-B cells. Thus, paraformaldehyde treatment of antigen-pulsed EBV-B cells did not impair their ability to trigger proliferation of antigen-specific Tbl, and EBV-B cells pulsed with antigen in the presence of autologous TT-specific T cell blasts did not present antigen to resting T cells. Furthermore, antigen-specific proliferation of resting T cells triggered by monocytes was enhanced rather than suppressed by EBV-B cells. The addition of partially purified human IL 1 allowed EBV-B cells to present TT antigen to resting T cells, suggesting that failure to secrete IL 1 contributed to the failure of EBV-B cells to present antigen. IL 1 could not be detected in supernatants of EBV-B cells stimulated with Staphylococcus epidermidis, concanavalin A, and TT antigen in the presence or absence of up to 5% autologous T cells. The differential capacity of EBV-B cells to present antigen to resting T cells vs activated T cells correlated with the T cell requirement for IL 1, because a rabbit antibody to human IL 1 inhibited the monocyte-supported proliferation of resting T cells but not that of activated T cells. These results suggest that the inability of EBV-B cells to present antigen to resting T cells is related to their inability to secrete detectable IL 1.

Adult↗
PubMed1986

Effect of gamma radiation on resting B lymphocytes. I. Oxygen-dependent damage to the plasma membrane results in increased permeability and cell enlargement.

Although the susceptibility of resting B lymphocytes to radiation-induced interphase death is well known, the mechanism by which this occurs is not understood. In this report, we use three measures of plasma membrane integrity (increase in cell volume, uptake of trypan blue, and release of 51Cr) to assess the effect of radiation on the resting B cell plasma membrane. The delivery of 500 to 1000 rad caused the majority of resting B cells to enlarge slightly, whereas 3000 rad caused virtually all of the cells to approximately double in size within 3 to 4 hr. Measurement of the release of 51Cr from resting B cells revealed a similar relationship between the dose of radiation and the loss of radioactive label. Trypan blue exclusion was also found to diminish as a function of radiation dose. An analysis of a variety of lymphoid cells suggested that sensitivity to the membrane damaging effects of gamma radiation was in the order of resting B cells greater than resting T cells greater than a long-term L3T4+ T cell clone greater than a B cell lymphoma. LPS-induced B cell blasts treated with 3000 rad were equivalent to 1000 rad-treated resting B cells. The effects of the gamma radiation could be ameliorated by excluding oxygen (a diradical molecule that can potentially enhance the generation and propagation of highly reactive free radicals) at the time of irradiation, or by adding the free radical scavenging agent cysteamine. These data are compatible with the hypothesis that gamma radiation results in damage to the plasma membrane of resting lymphocytes via the generation of highly reactive free radical species. This damage is reflected in a rapid increase in plasma membrane permeability and swelling of the cells, and may play a major role in causing interphase death.

Animals↗
PubMed1979

Noninvasive assessment of hemodynamic effects of mitral valve commissurotomy during rest and exercise in patients with mitral stenosis.

Noninvasive radionuclide angiocardiography (RNA) provides simple and accurate assessment of parameters of cardiac function during rest and during maximal exercise. Left ventricular function was assessed by RNA in nine patients with isolated mitral stenosis before and approximately 6 months after mitral commissurotomy. Before operation, the mean mitral valve gradient was 14.0 +/- 2.8 mm Hg, and the mean mitral valve area was 1.20 +/- 0.3 cm2. Each patient was evaluated at rest and during maximal exercise on an isokinetic bicycle ergometer before and after commissurotomy. Heart rate, ejection fraction, end-diastolic volume, stroke volume, pulmonary transit time, cardiac output, and diastolic ventricular filling rate were determined by the radionuclide technique. Before operation, patients with mitral stenosis had characteristic changes from rest to exercise which supported restriction to diastolic ventricular filling as the primary limitation in generating a cardiac output during exercise. The stroke volume was unchanged from rest to exercise. Thus the cardiac output during exercise was heart rate dependent. However, after commissurotomy the stroke volume increased from rest to exercise. Therefore, cardiac output during exercise was achieved by heart rate and an augmented stroke volume. Moreover, the pulmonary transit time was reduced during rest and exercise after operation. The maximum ventricular ejection and filling rates were markedly increased during rest and exercise after commissurotomy. These differences in hemodynamic parameters at rest and during exercise document the mechanics of increased exercise tolerance in patients with mitral stenosis after mitral commissurotomy.

Adult↗
PubMed1982

[Active metabolic processes in resting cells].

A number of intracellular metabolic processes are activated when cells proceed from proliferation to rest. These processes may be classified into 3 main categories: processes regulating the transition of cells from proliferation to rest; metabolic reactions necessary for the suppression of cell proliferation; processes required by a resting cell to maintain viability. Among the last category 2 groups of processes seem to be particularly important: a high rate of macromolecular turnover and an inhancement in the activity of catabolic enzymes. The high rate of RNA and protein turnover prevents the unbalanced cell growth and their death while the enhanced activity of catabolic enzymes maintains partial autolysis of resting cell compensating for the insufficient supply of nutrients due to a decreased external membrane permeability for some low molecular compounds. Thereupon, both these processes provide for the resistance of resting cells against unfavourable ambient effects allowing them to preserve proliferative potentials. Consequently the resting cells are in a special physiological state securing their self-maintenance under conditions of long-lasting absence of proliferation. The ability of cells to pass into a resting state may be regarded as a common feature of living systems acquired in the course of evolution. A co-ordinated activation of certain complexes of metabolic processes appears to be a general principle of resting cells existence in the animate nature.

Acetylation↗
PubMed1993

Functional role of charybdotoxin-sensitive K+ channels in the resting state of cerebral, coronary and mesenteric arteries of the dog.

To determine the possible role of Ca(++)-activated K+ (KCa) channels in the regulation of resting tone of arteries, the effects of agents that interact with these channels on tension and 86Rb efflux were examined in endothelium-denuded strips of cerebral (middle cerebral, posterior cerebral and basilar), coronary and mesenteric arteries of the dog. Strips of cerebral arteries maintained a myogenic tone; i.e., the resting tone decreased when either the Krebs' solution was replaced with a Ca(++)-free solution or nifedipine was added. The addition of charybdotoxin, a blocker of large conductance KCa channels, to the resting strips (strips at a resting state) caused a concentration-dependent contraction in the cerebral arteries but not in the coronary or mesenteric artery. In resting strips preloaded with 86Rb, the basal 86Rb efflux rate constant was significantly greater in the cerebral arteries than in the coronary and mesenteric arteries. The addition of nifedipine to the resting strips decreased the basal 86Rb efflux rate constant in the cerebral and coronary arteries. Effects of nifedipine on tension and 86Rb efflux in 20.9 mM K(+)-contracted strips of the mesenteric artery were comparable to the effects of this blocker in the resting strips of the middle cerebral artery. The 86Rb efflux rate constant during the stimulation with 65.9 mM K+ was similar for the middle cerebral and mesenteric arteries. Studies using 1- or 5-min pulse labeling with 45Ca demonstrated increased basal 45Ca influx in the resting state of cerebral arteries compared with the coronary and mesenteric arteries.(ABSTRACT TRUNCATED AT 250 WORDS)

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1993

Mitogen activation of resting lymphocytes exposes cryptic insulin receptors.

Mitogen activation of resting lymphocytes induces expression of high affinity insulin receptors on the plasma membrane. The mechanism underlying this effect on insulin receptor expression was examined by comparing levels of insulin receptor mRNA and protein in resting and mitogen-activated rodent lymphocytes. Analysis of RNA levels indicated that resting and concanavalin A-activated lymphocytes contained equivalent amounts of insulin receptor mRNA with predominant transcripts of 7.9 and 9.5 kilobases. Although little or no insulin binding was detectable on intact resting lymphocytes, detergent solubilization of these cells resulted in the appearance of readily detectable insulin binding activity that could be immunoprecipitated with anti-insulin receptor antibodies. Detergent-solubilized resting and mitogen-activated lymphocytes expressed equivalent amounts of insulin receptors that bound insulin with similar affinity (KD = 90 pM) and migrated on reduced SDS-polyacrylamide gels with apparent masses of approximately 130 and approximately 95 kDa. Insulin receptors from resting lymphocytes appeared to be associated with the plasma membrane since 125I labeling of intact lymphocytes radiolabeled the insulin receptor, insulin binding activity was detected in membrane fractions of hypotonically lysed cells, and trypsin treatment of intact cells destroyed > 90% of the insulin binding activity in detergent extracts. These results suggest that resting lymphocytes express insulin receptor mRNA and protein and that mitogen activation exposes cryptic insulin receptors present in the plasma membrane of resting lymphocytes.

Animals↗