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PubMed1996

Mechanisms of recovery from mechanical injury of cultured rat hepatocytes.

The mechanism(s) whereby hepatocytes restore denuded areas remains unknown. We therefore studied the recovery of denuded areas made in monolayers of primary cultures of rat hepatocytes. Minimal recovery occurred in cells plated on plastic. Plating on Matrigel produced modest recovery (25% at 24 h), whereas plating on a type I collagen substrate resulted in > 70% recovery at 24 h. The rate of recovery on collagen could be attenuated by a monoclonal antibody directed against the extracellular domain of the beta 1-integrin subunit. Monoclonal antibodies directed against CD44 (the hyaluron receptor) and E-cadherin did not influence the rate of recovery. Recovery could be stimulated, in a dose-dependent fashion, by epidermal and hepatocyte growth factors. The effects of epidermal and hepatocyte growth factors to promote recovery occurred in the absence of 5-bromo-2'-deoxyuridine uptake, suggesting a proliferation-independent mechanism. Transforming growth factor-beta 1 inhibited recovery. Exposure to selected cytokines (interleukins 1 and 2), an adenine nucleotide [adenosine 5'-O-(3-thiotriphosphate)], adenosine, pertussis toxin, and selected agents that bind to fibronectin and other matrix component adhesive sites (heparin and the RGD peptide) did not influence the rate of recovery of hepatocytes. However, the peptide DGEA, which can bind to collagen adhesive sites, attenuated recovery. These studies demonstrate that primary cultures of rat hepatocytes require a particular type of extracellular matrix to renew denuded areas and that the beta 1-integrin subunit may be involved in this recovery process. Hepatocyte recovery of denuded areas can be modulated by growth factors in both a stimulatory (epidermal and hepatocyte growth factors) and an inhibitory (transforming growth factor-beta 1) fashion.

Animals↗

PubMed1995

Dynamics of early postischemic myocardial functional recovery. Evidence of reperfusion-induced injury?

BACKGROUND: The present study was designed to explore the relation between the duration of ischemia and the rate and extent of myocardial functional recovery after reperfusion. METHODS AND RESULTS: Isolated rat hearts were perfused with blood from a support animal for 15 minutes (flow rate, 2.5 mL/min; perfusion pressure, 60.1 +/- 1.3 mm Hg). Control left ventricular developed pressure (LVDP) was measured, and the hearts (six per group) were subjected to 10, 20, 30, 40, 50, 60, 70, or 80 minutes of global ischemia (37 degrees C) and 60 minutes of reperfusion. Pacing (320 beats per minute) was instituted before and after ischemia. In all groups, transient arrhythmias occurred at the onset of reperfusion, to be followed by an early phase of recovery that peaked after 2 to 3 minutes of reperfusion. The relation between the extent of this initial recovery and the duration of preceding ischemia was described by a bell-shaped curve. Thus, the maximum initial mean recovery after 10, 20, 30, 40, 50, 60, 70, or 80 minutes of ischemia was 97%, 108%, 145%, 154%, 118%, 34%, 41%, and 24%, respectively, of preischemic LVDP. Possibly indicative of reperfusion-induced injury, LVDP then declined in all groups so that after 20 minutes of reperfusion, the mean recovery was 63%, 53%, 48%, 50%, 56%, 12%, 9%, and 5%, respectively. In the 10-, 20-, 30-, and 40-minute ischemia groups, there then was a secondary increase in LVDP, possibly indicating the start of recovery from stunning. After 60 minutes of reperfusion, the mean recovery of LVDP was 82%, 65%, 59%, 54%, 47%, 9%, 7%, and 4%, respectively; this second phase of recovery was inversely proportional to the duration of ischemia. To define the early phase of recovery that had been obscured by reperfusion-induced arrhythmias, we repeated the experiments with the inclusion of a cardioplegic infusion (St Thomas' solution for 2 minutes before ischemia). This significantly reduced the incidence of ventricular fibrillation during early reperfusion. The extent of the initial postischemic recovery of LVDP was similar to that observed without cardioplegia; however, the mean secondary recovery was greater in all groups. Again, the relation of early transient (2 to 5 minutes) recovery to the duration of ischemia was represented by a bell-shaped curve, whereas the secondary recovery was inversely related. CONCLUSIONS: Although the results of the present study confirm the protective properties of cardioplegia, they also shed some light on the nature of reperfusion-induced injury and myocardial stunning and their complex relation to the severity of the preceding ischemia.

Animals↗

PubMed2006

The top ten concerns about recovery encountered in mental health system transformation.

The notion of "recovery" has recently taken center stage in guiding mental health policy and practice. However, it is not yet clear what the term means and what is to be entailed in transforming the nation's mental health system to promote it. The authors discuss the various meanings of recovery as applied to mental illness and list the top ten concerns encountered in efforts to articulate and implement recovery-oriented care. These concerns include the following: recovery is old news, recovery-oriented care adds to the burden of already stretched providers, recovery involves cure, recovery happens to very few people, recovery represents an irresponsible fad, recovery happens only after and as a result of active treatment, recovery-oriented care is implemented only through the addition of new resources, recovery-oriented care is neither reimbursable nor evidence based, recovery-oriented care devalues the role of professional intervention, and recovery-oriented care increases providers' exposure to risk and liability. These concerns are addressed through discussion of the two over-arching challenges that they pose, namely the issues of resources and risk.

Health Resources↗

PubMed2006

Trajectories of zooplankton recovery in the Little Rock Lake whole-lake acidification experiment.

Understanding the factors that affect biological recovery from environmental stressors such as acidification is an important challenge in ecology. Here we report on zooplankton community recovery following the experimental acidification of Little Rock Lake, Wisconsin, USA. One decade following cessation of acid additions to the northern basin of Little Rock Lake (LRL), recovery of the zooplankton community was complete. Approximately 40% of zooplankton species in the lake exhibited a recovery lag in which biological recovery to reference basin levels was delayed by 1-6 yr after pH recovered to the level at which the species originally responded. Delays in recovery such as those we observed in LRL may be attributable to "biological resistance" wherein establishment of viable populations of key acid-sensitive species following water quality improvements is prevented by other components of the community that thrived during acidification. Indeed, we observed that the recovery of species that thrived during acidification tended to precede recovery of species that declined during acidification. In addition, correspondence analysis indicated that the zooplankton community followed different pathways during acidification and recovery, suggesting that there is substantial hysteresis in zooplankton recovery from acidification. By providing an example of a relatively rapid recovery from short-term acidification, zooplankton community recovery from experimental acidification in LRL generally reinforces the positive outlook for recovery reported for other acidified lakes.

Animals↗

PubMed1997

Respiratory responses to passive and active recovery from exercise.

To investigate the effect of the neural components associated with leg movements on the control of ventilation during recovery from exercise, we recorded the minute ventilation (VE), oxygen uptake (VO2), and carbon dioxide output (VCO2) of eight normal volunteers during recovery from moderate, steady-state cycle exercise (170 W). The recovery phases were undergone separately under two different conditions: 5 min of rest (passive recovery) on a bicycle ergometer and 3 min of pedaling at a work rate of 0W (active recovery) followed by 2 min of rest. The phase-1 responses were observed in all the variables studied at the transition of passive recovery but not in the active recovery phase. The kinetics of VCO2, during the off-transition were significantly faster than those of VE in both recoveries, indicating that the decreases in VCO2 could precede the decreases in VE. Although the levels of VE and VCO2 during active recovery were significantly higher than those during passive recovery, the decline in VE was closely proportional to that of VCO2 under both recovery conditions, with resultant indications of similar VE-VCO2 regression lines. These findings suggest that the flux of CO2 to the lungs is an important determinant of ventilatory drive during recovery, and that neither central command nor neural afferents from contracting muscles are requisite for the control of ventilation during recovery from exercise.

Adult↗

PubMed2001

Nasal strips do not affect cardiorespiratory measures during recovery from anaerobic exercise.

Nasal dilators supposedly aid recovery from exercise by reducing nasal airway resistance. Research has focused on the effectiveness of nasal dilators during exercise. The purpose of this study was to examine the effects of nasal dilators on heart rate (HR), minute ventilation (VE), and oxygen consumption (Vo2) during recovery from anaerobic exercise. Fourteen subjects (19-32 years) performed a modified Cunningham-Faulkner anaerobic treadmill test (1-minute walk at 2.0 miles per hour [mph], 0% grade; 1-minute jog at 5 mph, 0% grade; and sprint at 8 mph, 20% grade) under 3 randomly assigned conditions: (a) control, (b) nasal strip, and (c) placebo nasal strip. A 10-minute recovery period consisting of 5 minutes of walking (2 mph, 0% grade) and 5 minutes of passive recovery (seated) was completed. During the test and recovery periods, the participant wore a fireman's face mask to allow for simultaneous sampling of nose and mouth breathing. Vo2 and VE were monitored by a TEEM 100 metabolic analyzer. Each subject wore a Polar Heart Watch to monitor HR every minute during recovery. Mean time to exhaustion was 48.4 seconds (+/-14.9). One-way repeated-measures analyses of variance (ANOVAs) indicated no significant nasal dilator effect on 5-minute recovery HR or 10-minute recovery HR, 5-minute recovery Vo2 or 10-minute recovery Vo2, and 5-minute recovery VE or 10-minute recovery VE. Nasal strips appear to have no significant impact during recovery from anaerobic exercise.

Adult↗

PubMed2005

[Postoperative recovery of aneurysm of posterior communicating artery-induced oculomotor palsy: clinical observation of 52 cases].

OBJECTIVE: To explore the prognosis of aneurysm of posterior communicating artery-induced oculomotor palsy after surgery. METHODS: Fifty-two patients with aneurysm of posterior communicating artery-induced oculomotor palsy, 12 males and 40 females, aged 57, diagnosed by CT, MRI, and digital subtraction angiography, were divided into 2 groups: group A (n = 20, receiving simple clipping of the aneurysmal neck) and group B (n = 32, undergoing clipping of the aneurysmal neck followed by nerve decompression such as resection or puncture of the aneurysmal sac), and were followed up for 12 months (2-48 months). RESULTS: In the group A 10 patients were operated on within 14 days after the onset of oculomotor palsy showed complete recovery of the oculomotor nerve function within 40 days after operation; 8 patients were operated on within 14-30 days after the onset of oculomotor palsy showed complete recovery within 30-90 days after operation in 7 patients and incomplete recovery in 1 patient; and 2 patients were operated on 30 days after the onset of oculomotor palsy showed complete recovery within 6 months after operation in 1 patient and incomplete recovery in the other patient. In the group B 15 patients were operated on within 14 days after the onset of oculomotor palsy all showed complete recovery within 40 days after operation; 14 patients were operated on within 14-30 days after the onset of oculomotor palsy showed complete recovery within 30-90 days after operation in 12 patients and incomplete recovery in 2 patients; and 3 patients were operated on 30 days after the onset of oculomotor palsy showed complete recovery within 6 months after operation in 2 patients and incomplete recovery in the other one patient. There was no significant difference in the recovery rate between these 2 groups. Recovery of the oculomotor nerve function was remarkably correlated with the time of operation after the onset. CONCLUSION: Early diagnosis and treatment help recover the oculomotor nerve function. The recovery of the oculomotor nerve function is not related to the operation protocols.

Adult↗

PubMed2004

Time course of functional recovery after coronary artery bypass grafting surgery according to the preoperative reversibility of perfusion impairment on myocardial SPECT.

PURPOSE: Ischaemic myocardial dysfunction shows different time courses of functional recovery according to the pathophysiological characteristics of the dysfunction. In this study, we investigated the time course of functional recovery according to the preoperative reversibility of perfusion impairment on myocardial single-photon emission computed tomography (SPECT) after revascularisation surgery. METHODS: Forty-eight patients (42 men and 6 women; mean age 59+/-9 years) who underwent revascularisation surgery were included in the study. 201Tl rest/dipyridamole stress (99m)Tc-sestamibi gated SPECT was performed 10+/-8 days before (preoperative), 105+/-13 days after (early follow-up) and 497+/-66 days after (late follow-up) surgery. Using a 20-segment model, segmental perfusion and thickening were quantified with automatic software. As an indicator of the reversibility of perfusion impairment, a reversibility score (RevS) was defined as a measure of rest minus stress perfusion values. Segmental dysfunction and functional recovery were defined from quantified thickening values. Function-recovered segments were divided into early recovery and late recovery groups, and preoperative perfusion status was compared in these groups. Function-recovered segments were also re-classified into high-RevS and low-RevS groups according to the preoperative RevS, and the time courses of functional recovery were investigated in each group. RESULTS: A total of 502 segments were included in the analysis and 263 were finally classified as function-recovered segments. Of these, 172 were in the early recovery and 91 in the late recovery group. In terms of preoperative perfusion status, RevS was 8.9+/-10.8 in the early recovery group and 5.4+/-11.0 in the late recovery group (P=0.01). When all 502 segments were classified by RevS, no difference in the proportion of final function recovery was observed between the high-RevS and the low-RevS group (54% vs 51%). However, the proportion of early recovery was higher in the high-RevS group (73%) than in the low-RevS group (57%) (P=0.01). CONCLUSION: Ischaemic dysfunctional myocardium with reversible perfusion impairment tends to recover function earlier after revascularisation surgery than myocardium with a persistent decrease in perfusion.

Coronary Artery Bypass↗

PubMed2005

Modeling behavioral recovery following lesion induction in the rat dentate gyrus.

Unilateral entorhinal lesions have enjoyed immense popularity as a model of recovery from damage. In part, the popularity has been supported the laminar organization of the hippocampal formation, which allows for the dissection of the contribution of individual afferent pathways to the recovery process. The commissural/associational pathway is of particular interest, since electrophysiological and gross anatomical data, although limited, have correlated sprouting in this pathway with behavioral recovery. Unfortunately, information relating recovery to synaptic structure is lacking. Addressing this issue, two analyses were conducted. Initially, a quantitative review of the literature reporting behavioral recovery following this type of lesion was conducted using meta-analytic techniques. Using this detailed information across decades of research, multiple linear regression analysis was conducted to address whether the morphological correlates of recovery could predict behavioral recovery. This resulted in an equation relating morphology and recovery that stood up well to several diagnostic tests. Moreover, this model suggests that synapse structure (in particular, synapse size and curvature, as well as terminal compartmentalization and the density of multi-synaptic terminals) holds a greater potential to predict behavioral recovery than increases in synapse number, which is typically seen as the optimal anatomical measure of recovery. This initial attempt to identify, quantify, and validate a model of lesion recovery is an important initial step in understanding how synaptic morphology may help mediate recovery of function.

Animals↗

PubMedDate not supplied

Abnormal heart rate recovery immediately after treadmill testing: correlation with clinical, exercise testing, and myocardial perfusion parameters.

BACKGROUND: The increase in heart rate during exercise is considered to be attributed to sympathetic system activation combined with parasympathetic withdrawal. The prognostic importance of the chronotropic response to exercise and heart rate recovery 1 minute after exercise has already been established. The purpose of this study was to evaluate heart rate recovery as an index of myocardial ischemia, by correlating heart rate recovery with known parameters of myocardial ischemia. METHODS AND RESULTS: Included in the study were 304 consecutive patients (73% men), aged 34 to 82 years. Patients whose heart rate recovery value or myocardial perfusion imaging could have been influenced by factors other than ischemic disease were excluded from the study. The patients underwent single photon emission computed tomography myocardial perfusion imaging combined with symptom-limited exercise testing with thallium 201 or technetium 99m tetrofosmin. The value for heart rate recovery was defined as the decrease in heart rate from peak exercise to 1 minute after termination of exercise. For semiquantitation of the scintigram, the uptake of the radiotracer was graded on a scale from 0 to 4. Twenty-one beats per minute was defined as the lowest normal value for heart rate recovery. We found 74 patients (24%) with an abnormal value. We also found a significant correlation between heart rate recovery 1 minute after exercise and stress myocardial perfusion score. In addition, there was a statistically significant relationship between heart rate recovery and chronotropic variables. Patients with an abnormal value of heart rate recovery were generally of an older age, were more likely men, had a higher frequency of risk factors for coronary artery disease, were mostly taking cardioactive medications, had lower efficiency during treadmill testing, and had more pathologic findings on the scintigram. CONCLUSIONS: Myocardial ischemia, as assessed by myocardial perfusion imaging, is an important correlate of heart rate recovery. There is a significant correlation between chronotropic variables during exercise testing and heart rate recovery 1 minute after exercise. It seems that the heart rate recovery value 1 minute after peak exercise may be considered a reliable index of the severity of myocardial ischemia.

Adult↗

PubMed2005

Effects of immediate post-game recovery procedures on muscle soreness, power and flexiblity levels over the next 48 hours.

This study investigated whether or not immediate post-game recovery procedures could enhance the rate of recovery in Australian football players in the first 48 hr after a game. Control, stretch, pool walking and hot/cold recoveries were trialled. Typical next day recovery training (25 min of pool exercise) was also performed after each game. Muscle soreness ratings and measures of flexibility (sit and reach) and power (6-s cycling sprint and vertical jump) were obtained 45 hr pre-game (Thursdays) (baseline), 15 hr post-game (Sundays, prior to "next day" recovery) and 48 hr post-game (Mondays). Performance ratios (Sunday and Monday scores divided respectively by the Thursday score) were used as the primary index of recovery. Muscle soreness was significantly greater (p<0.01) than baseline on both Sunday and Monday in all conditions, but no differences between the three recoveries and control were evident. On Sunday, vertical jump and 6-s work and power scores were only significantly lower than baseline values in control and performance ratios recorded two significant differences (vertical jump: pool walking > control, p<0.01; 6-s power: stretch > control, p<0.01) and moderate to large effect sizes (>0.3). No differences were found between the three experimental recoveries. On Monday no significant differences were recorded in performance between the recoveries and the effect sizes were of lower magnitude. In conclusion, recovery of muscle soreness, flexibility and power at 48 hr post-game was not significantly enhanced by performing an immediate post-game recovery beyond that achieved by performing only next day recovery training.

Adult↗

PubMed2006

Epidemiology of renal recovery after acute renal failure.

PURPOSE OF REVIEW: Recovery of renal function after acute renal failure is an important clinical determinant of patient morbidity. Herein, the epidemiology of renal recovery after acute renal failure will be described, along with potential predictive factors and interventions. RECENT FINDINGS: Renal recovery has been variably defined, most often as recovery to independence from renal replacement therapy. A recent consensus definition for acute renal failure has been published and included provisions for defining renal recovery. Renal recovery to renal replacement therapy independence occurs in the majority by hospital discharge and peaks by 90 days. All of older age, female sex, co-morbid illnesses, especially chronic kidney disease, and late initiation of renal replacement therapy or conventional intermittent renal replacement therapy have been coupled with non-recovery. Analysis of the literature suggests several interventions may influence recovery. SUMMARY: The prognosis is generally good for recovery after acute renal failure. Most patients will be independent of renal replacement therapy by 90 days. Additional research is necessary, however, to understand recovery rates not only to independence from renal replacement therapy, but also to complete and partial recovery. Future studies need to consider the health economic implications for survival and non-recovery. Finally, questions on the role of various interventions require characterization in randomized controlled trials to determine how they may influence renal prognosis.

Acute Kidney Injury↗

PubMed1989

Spontaneous recovery of residual neuromuscular blockade after atracurium or vecuronium during isoflurane anaesthesia.

With atracurium and vecuronium, spontaneous recovery of residual neuromuscular blockade monitored electromyographically during 0.5% isoflurane anaesthesia was studied in 60 patients undergoing plastic surgery. After thiopentone, in random order, either atracurium 0.5 mg kg-1 or vecuronium 0.1 mg kg-1 was administered and isoflurane added to N2O and O2 mixture. Following spontaneous recovery of both the single twitch amplitude (T1) to 75% of the control value and the train-of-four ratio (TOF ratio) to 75%, incremental doses of the relaxant were given to maintain the T1 at less than 10%. Before the end of surgery, the blockade was again permitted to recover spontaneously. During the initial spontaneous recovery, the mean recovery time of T1 from 25% to 75% (the recovery index) with atracurium was longer (P less than 0.001) than that with vecuronium (13.2 min and 10.1 min, respectively) but, during the second recovery, the mean recovery index was shorter (P less than 0.05) with atracurium than with vecuronium (16.1 min and 19.8 min, respectively). The recovery time from T1 75% to TOF ratio 75%, indicating the recovery rate of residual neuromuscular blockade, with atracurium was about 15 min after both the initial and the second recoveries. With vecuronium, the respective recovery times were significantly (P less than 0.001) longer (25.6 min and 38.5 min, respectively). It is concluded that with vecuronium there is slower spontaneous recovery of residual neuromuscular blockade than with atracurium.

Adult↗

PubMed2004

Passive versus active recovery during high-intensity intermittent exercises.

PURPOSE: To compare the effects of passive versus active recovery on muscle oxygenation and on the time to exhaustion for high-intensity intermittent exercises. METHODS: Twelve male subjects performed a graded test and two intermittent exercises to exhaustion. The intermittent exercises (15 s) were alternated with recovery periods (15 s), which were either passive or active recovery at 40% of .VO2max. Oxyhemoglobin was evaluated by near-infrared spectroscopy during the two intermittent exercises. RESULTS: Time to exhaustion for intermittent exercise alternated with passive recovery (962 +/- 314 s) was significantly longer (P < 0.001) than with active recovery (427 +/- 118 s). The mean metabolic power during intermittent exercise alternated with passive recovery (48.9 +/- 4.9 mL.kg-1.min-1) was significantly lower (P < 0.001) than during intermittent exercise alternated with active recovery (52.6 +/- 4.6 mL.kg-1.min-1). The mean rate of decrease in oxyhemoglobin during intermittent exercises alternated with passive recovery (2.9 +/- 2.4%.s-1) was significantly slower (P < 0.001) than during intermittent exercises alternated with active recovery (7.8 +/- 3.4%.s-1), and both were negatively correlated with the times to exhaustion (r = 0.67, P < 0.05 and r = 0.81, P < 0.05, respectively). CONCLUSION: The longer time to exhaustion for intermittent exercise alternated with passive recovery could be linked to lower metabolic power. As intermittent exercise alternated with passive recovery is characterized by a slower decline in oxyhemoglobin than during intermittent exercise alternated with active recovery at 40% of .VO2max, it may also allow a higher reoxygenation of myoglobin and a higher phosphorylcreatine resynthesis, and thus contribute to a longer time to exhaustion.

Adult↗

PubMed2002

Use of a pool-raft system for recovery of horses from general anesthesia: 393 horses (1984-2000).

OBJECTIVE: To describe the pool-raft recovery system protocol and to evaluate the clinical outcome in horses that underwent recovery from general anesthesia using this system. DESIGN: Retrospective study. ANIMALS: 393 horses that underwent recovery from general anesthesia in the pool-raft system. PROCEDURE: Anesthetic records were examined from horses recovered from anesthesia in the pool-raft system between January 1984 and December 2000. Complete medical records of horses were examined when available. Information regarding the anesthetic and recovery period was recorded. Horses first recovered from general anesthesia in the pool-raft and, once awake, were transported to a recovery stall and lowered to the floor in a standing position. RESULTS: 351 horses underwent 1 pool-raft recovery, and 42 horses underwent multiple pool-raft recoveries. Most horses were recovered from general anesthesia within the pool-raft system to safeguard repair of a major orthopedic injury. During 471 pool-raft recoveries, 34 (7%) horses had complications within the recovery pool and 62 (13%) had complications within the recovery stall. Deaths resulted from complete failure of internal fixation, pulmonary dysfunction, or a combination of pulmonary dysfunction and fixation failure in 2% (10/471) of horses that underwent pool-raft recoveries. CONCLUSIONS AND CLINICAL RELEVANCE: The pool-raft system is a good option for recovery from general anesthesia. Although not a fail-safe system, it appears to decrease the complications of recovering horses in a high-risk category. Potential disadvantages of this system are added expense and manpower necessary in building, maintenance, and usage, as well as size limitations of the raft itself.

Anesthesia Recovery Period↗

PubMed1978

Anoxic block and recovery of axoplasmic transport and electrical excitability of nerve.

Axoplasmic transport of cat sciatic nerves was studied in vitro in a chamber in which maximal alpha action potentials could also be elicited. After initiation of N2 anoxia, electrical responses fell to zero at an average time of 22 min. A shorter time to zero of 11 min was seen during a second period of anoxia. A good recovery of both action potential responses and axoplasmic transport occurs after a period of anoxia lasting 1--1.5 hr. An apparent failure of recovery of axoplasmic transport was seen after 2 hr of anoxia with a good recovery of electrical responses. Axoplasmic transport tended to return toward normal when more time was allowed for recovery after anoxia. An adequate supply of approximately P was shown to be present by measurement of ATP and creatine phosphate levels. The delay in recovery of transport thus signifies a failure of utilization of approximately P by the transport mechanism. Longer periods of anoxia and recovery were limited in vitro and for this reason, ischemic anoxia was produced in vivo. Blood pressure cuffs were placed on the upper thigh of cats and maintained for times of 1--8 hr at pressures of 300-310 mm Hg. Then, recovery times up to 7 days were allowed. It was shown that axoplasmic transport could gradually recovery after an anoxia lasting up to 6-7 hr if sufficient recovery times were allowed. A possible explanation for the delay in the recovery of axoplasmic transport and the disassociation in the earlier recovery of electrical responses as against the recovery of transport was discussed.

Action Potentials↗

PubMed1995

Prolonged recovery from exercise-induced asthma with increasing age in childhood.

It has been suggested that children with asthma recover more quickly from exercise-induced bronchoconstriction than adults. On the basis of clinical observation we hypothesized that recovery rate from exercise-induced asthma (EIA) in childhood also decreases with age. In 14 children (aged 7-12 years) with a history of EIA, we measured spontaneous recovery from bronchoconstriction induced by two different stimuli: exercise and histamine. The children visited the laboratory three times. After a screening exercise test on the first visit, standardized bronchoprovocation tests with either exercise or histamine were performed on the following two visits in random order. The degree of bronchoconstriction induced by histamine was matched for that observed after exercise. During recovery, forced expiratory volume in 1 second (FEV1) was measured repeatedly up to 2 hours postchallenge. The recovery rate (% increase in FEV1/min) was calculated from the linear slope of the time-response curve. Differences in recovery rate between the two stimuli were analyzed by paired t-test, and age-related differences were analyzed using multiple regression analysis. For the group as a whole, recovery rate was not different between the two stimuli (mean +/- SD: 1.22 +/- 0.91 for exercise, and 1.46 +/- 0.65, for histamine, P = 0.31). However, the recovery rate for exercise-induced bronchoconstriction decreased significantly with age (r = -0.74, P = 0.003), in contrast to the recovery rate for histamine (r = -0.15, P = 0.60). Consequently, in the oldest age group (11-12 years, n = 5) recovery rate from exercise challenge was significantly slower than in the younger age group (7-10 years, n = 9), i.e., 0.54 +/- 0.17 and 1.60 +/- 0.93, respectively, P = 0.009, and slower than the recovery rate from histamine challenge: 0.54 +/- 0.17 and 1.33 +/- 0.54, respectively, P = 0.03. In the younger age group the recovery rates from exercise and histamine were not different (1.60 +/- 0.93 and 1.54 +/- 0.73, respectively, P = 0.83). We conclude that recovery from EIA in childhood decreases with increasing age. These data suggest that the mechanism of exercise-induced asthma in childhood changes with age. This might be due to changes in mediator production or response to mediator release.

Age Factors↗

PubMed1996

Lactate kinetics during passive and partially active recovery in endurance and sprint athletes.

We investigated the effects of passive and partially active recovery on lactate removal after exhausting cycle ergometer exercise in endurance and sprint athletes. A group of 14 men, 7 endurance-trained (ET) and 7 sprint-trained (ST), performed two maximal incremental exercise tests followed by either passive recovery (20 min seated on cycle ergometer followed by 40 min more of seated rest) or partially active recovery [20 min of pedalling at 40% maximal oxygen uptake (VO2max) followed by 40 min of seated rest]. Venous blood samples were drawn at 5 min and 1 min prior to exercise, at the end of exercise, and during recovery at 1, 2, 3, 4, 5, 6, 8, 10, 15, 20, 30, 40, 50, 60 min post-exercise. The time course of changes in lactate concentration during the recovery phases were fitted by a bi-exponential time function to assess the velocity constant of the slowly decreasing component (tau 2) expressing the rate of blood lactate removal. The results showed that at the end of maximal exercise and during the 1st min of recovery, ET showed higher blood lactate concentrations than ST. Furthermore, ET reached significantly higher maximal exercise intensities [5.1 (SEM 0.5) W.kg-1 vs 4.0 (SEM 0.3) W.kg-1, P < 0.05] and VO2max [68.4 (SEM 1.1) ml.kg-1.min-1 vs 55.5 (SEM 5.1) ml.kg-1.min-1, P < 0.01]. There was no significant difference between the two groups during passive recovery for tau 2. During partially active recovery, tau 2 was higher than during passive recovery for both groups (P < 0.001), but ET recovered faster and sooner than ST (P < 0.05). Compared to passive recovery, the tau 2 measured during partially active recovery was increased threefold in ET and only 1.5-fold in ST. We concluded that partially active recovery potentiates the enhanced ability to remove blood lactate induced by endurance training.

Adult↗