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Results for “Recovery of Function”

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PubMed1990

Functional recovery after destruction of dopamine systems in the nucleus accumbens of rats. I. Behavioral and biochemical studies.

Bilateral 6-hydroxydopamine (6-OHDA) lesions in the nucleus accumbens of rats induced motor hypoactivity 7 days after the lesion. Spontaneous functional recovery of this impaired behavior occurred in 3-4 weeks. Behavioral and biochemical studies suggest that the hypoactivity is due to damage of the dopamine systems in the nucleus accumbens. The 6-OHDA lesions induced a decrease in the nucleus accumbens levels of dopamine and its metabolites of about 30% both 7 and 20 days after the lesion. The in vitro uptake of [3H]dopamine in nucleus accumbens tissue of the 6-OHDA-lesioned rats was decreased to the same extent at 7, 14 and 28 days after the lesion. Scatchard analysis of [3H]haloperidol binding studies in nucleus accumbens tissue revealed a shift from one type of binding site in tissue of sham-lesioned rats to two types of binding sites in tissue of 6-OHDA-lesioned rats 29 days after the lesion. This shift was not present in nucleus accumbens tissue 8 days after a 6-OHDA lesion. The spontaneously recovered rats showed an enhanced behavioral response upon administration of the dopamine agonist apomorphine. The present data suggest that the spontaneous functional recovery of impaired motor activity is caused by the development of supersensitivity of the dopamine receptor systems in the nucleus accumbens. This supersensitivity may be the result of increased affinity of one type of binding site or an increased number of functional binding sites.

Animals↗

PubMed1994

Stunning, preconditioning, and functional recovery after global myocardial ischemia.

Stunning (reversible myocardial ischemia without necrosis) occurs with induced global ischemia during cardiac operations and depresses the ability of the heart to utilize oxygen efficiently because less contractile work is developed per unit of oxygen utilized. Interestingly, regional studies have demonstrated dramatic infarct size reduction with stunning episodes before prolonged ischemia, a phenomenon known as myocardial preconditioning. It is postulated that the postischemic contractile dysfunction noted after stunning causes reduced energy demands, which "preconditions" myocardium to withstand a subsequent longer ischemic episode. Some evidence from regional studies suggests that preconditioning may improve functional recovery after ischemia. This study examined the complex relationship between stunning and preconditioning to functional recovery in a surgical setting of global ischemia. To study the effect of stunning, myocardial oxygen consumption, oxygen extraction, and functional indices of contractility were measured before and after isolated rabbit hearts were subjected to 10, 20, or 45 minutes of normothermic 37 degrees C global ischemic stun intervals. This demonstrated that while oxygen consumption and extraction quickly recover to prestun levels, contractility remains depressed well beyond the stun interval. To study the effect of preconditioning using stunning, isolated hearts were then subjected to 120 minutes of 34 degrees C cardioplegic-induced ischemia after preconditioning. Hearts received either modified St. Thomas cardioplegic solution as a control or cardioplegia administered after preconditioning with 37 degrees C ischemic stunning for 5, 10, 15, 20, or 45 minutes or multiple 5- or 10-minute stuns, with reperfusion before cardioplegic-induced ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1997

Facilitation of retinal function recovery by coumarin derivatives.

Ischemic retinopathy is a difficult disease to treat, although numerous drugs have been tried in the clinics. Coumarin was one of those tried as an anti-coagulant with a marginal efficacy. In this study, 15 coumarin derivatives were studied on the b-wave recovery in electroretinogram which is an indicator of the functional recovery of retina after ischemic insult. It was found that when positions 6, 7 and 8 were occupied by various functional groups, the b-wave recovery could be markedly enhanced. On the other hand, single occupation of position 3 with any functional group would cause damaging effects to the anti-ischemic activity. It is concluded that some coumarin derivatives with two or all of these positions at 6, 7 and 8 occupied by certain functional groups could result in useful drugs for the treatment of ischemic retinopathy.

Animals↗

PubMed1997

Serial recording of somatosensory and myoelectric motor evoked potentials: role in assessing functional recovery after graded spinal cord injury in the rat.

Accurate functional outcome measures are essential in assessing therapeutic interventions after experimental spinal cord injury (SCI). We examined the hypothesis that serial recording of somatosensory (SSEP) and myoelectric motor evoked potentials (mMEPs) would provide complementary information to standard methods of behavioral analysis in a rat model of SCI and would allow objective discrimination of functional recovery in sensory and motor tracts. Clip compression injury of varying severity (sham, 23 g, 34 g, 56 g) and transections were performed at T1 in adult rats. SSEPs were recorded from the right sensorimotor cortex (SMC) after stimulation of the contralateral hind paw; mMEPs were recorded from the paraspinal, quadriceps, and the tibialis anterior muscles after anodal stimulation of the SMC. The inclined plane and Tarlov techniques were used to assess clinical neurological function. All outcome measures were assessed weekly prior to and up to 6 weeks following injury. Changes in clinical neurological function as assessed by the inclined plane and Tarlov methods varied with increasing injury severity (R = -0.72 and R = -0.73, respectively). SSEP latency was strongly correlated with injury severity (R = 0.92) and with clinical behavioral scores (R = -0.93 for inclined plane). The tibialis anterior mMEP correlated significantly, though weakly, with changes in inclined plane (R = 0.49) and Tarlov scores (R = 0.41). Although the mMEPs were sensitive to the presence of SCI, these recordings did not discriminate between severities of injury. We conclude that serial recording of SSEPs but not myoelectric MEPs correlates closely with the extent and temporal course of clinical neurological recovery after graded SCI in the rat.

Animals↗

PubMedDate not supplied

Recovery functions of somatosensory vertex potentials in man: interaction of evoked responses from right and left fingers.

Somatosensory vertex potentials (SVPs) were examined in 12 healthy subjects in response to painful electrical stimulation of the finger. SVPs consisted of N1, P1, and N2. The average latencies of the 3 peaks were 150, 225, and 350 msec, respectively. The latency and amplitude of each potential were reproducible for each subject. Recovery functions of the SVPs were analyzed in 10 subjects. A pair of stimuli were delivered to the right or left finger with interstimulus intervals (ISIs) of 50, 100, 150, 200, 350, 500 and 650 msec. SVPs partially recovered with the shortest ISI (50 msec). Full recovery could not be obtained even with the longest ISI (650 msec). Differences in recoveries within 650 msec of ISI were not observed between right and left stimulations. To examine the interaction between SVPs evoked by right and left finger stimulation, recovery functions from prior contralateral finger stimulation were analyzed with the same ISIs. SVP recoveries for right after left or left after right patterns of stimulus delivery were nearly the same as those for ipsilateral ones. It is suggested that SVPs are generated at nearly the same site in the sensory pathway regardless of the side stimulated.

Adult↗

PubMedDate not supplied

Remedial therapy and functional recovery in a total population of first-stroke patients.

A consecutive series of 155 patients with a first-ever stroke and who were registered with the Oxfordshire Community Stroke Project (OCSP) were followed up. Their receipt of remedial therapy was recorded and their functional recovery was measured using the Barthel index of activities of daily living. Only a minority of patients received remedial therapy during the first 6 months after stroke. Those who were admitted to hospital during the first month following their stroke, or who were severely dependent, were significantly more likely to receive remedial therapy than those who remained in the community or were less dependent. A comparison of functional recovery amongst a matched subsample of patients who received remedial therapy and those who did not showed that there was comparable recovery amongst patients who did not receive remedial therapy.

Activities of Daily Living↗

PubMed1992

Functional recovery following reptilean (Calotus calotus) spinal cord transection.

Various approaches to remedy the effects of spinal cord injury have been suggested from time to time. One of these is to study the regeneration following spinal cord transection in phylogenetic lower species in order to gain some information from this for its application in non-regenerating spinal cord injuries in higher species. In the present study the functional recovery following spinal cord transection in a reptile (Calotus calotus) was studied in 30 animals, and it was observed that functional recovery was quite marked by 4 weeks and more or less comple by 6 weeks.

Animals↗

PubMed1995

Electromyographic study of functional recovery of free vascularized muscles grafted to the face.

The functional recovery of gracilis muscles grafted for treatment of facial paralysis in combination with a cross-face nerve graft was evaluated on the basis of electromyography in 98 cases. Initial action potentials were recorded, on average, 8 months after transplantation. There was a tendency for such potentials to appear earlier in the case of patients who finally attained good muscle activity. Action potentials were polyphasic in the early stage and of short duration and low amplitude. An increase in the amplitude and duration of potentials and a shortening of the distal latency were observed with increase in the numbers of reinnervated muscle fibers. Thereafter, there was a tendency toward decreases in the duration and number of spikes due to the increasing similarity in the distal latency of each neuromuscular unit. The grafted gracilis muscles attained a stable state about 1 year after the initial recording of action potentials. It was expected that spontaneous action potentials during rest might serve to indicate the condition of reinnervation. Their absence during the first few months after transplantation may suggest necrosis of the grafted muscle, while those of long duration and high amplitude observed after 1 postoperative year may be suggestive of disturbance in the reinnervation process. In this study, we could not find any significant difference in the reinnervation process between that of a gracilis muscle grafted following a cross-face nerve graft and a muscle reinnervated following nerve transection and repair. We therefore believe that free gracilis muscle transplantation combining a cross-face nerve graft is appropriate for the reconstruction of muscle function.

Action Potentials↗

PubMed1981

Spinal motoneuronal excitability in hyperkinesis: H-reflex recovery function and homosynaptic depression during wakefulness.

Variations in amplitude of the spinal monosynaptic H-reflex were examined during relaxed wakefulness in three unmedicated groups of subjects, hyperactive children (n=5), an age-matched group of control children (n=5), and a group of young adults (n=10), using techniques involving equal intensity percutaneous stimuli delivered in pairs or trains at varying rates. The paired-stimuli procedure generates a recovery function, the outstanding features of which are early depression, a peak of facilitation occurring between 100-300 msec, and complete recovery by 2-5 sec. Trains of stimuli delivered at rates greater than or equal to 1/sec effect a reduction in reflex amplitude which is termed homosynaptic depression. Both procedures revealed differences between hyperkinetic children and comparison groups. The paired-stimulus technique revealed a generalized reduction in excitability for hyperkinetic children for intervals extending up to 800 msec. In particular, hyperkinetic children were characterized by a significantly increased variability at the longer stimulus intervals. Hyperkinetic children also showed a more rapid reduction in reflex amplitude to initial stimuli in stimulus trains delivered at rates greater than or equal to 1/sec. Trains of stimuli at rates effecting facilitation in terms of the paired stimulus technique, i.e., 3,4 and 5/sec, revealed sustained amplitude enhancement for control subjects only. The recovery function data are consonant with spinal motoneuronal hypoexcitability in hyperkinetic children. Possible neruophysiological and neurochemical mechanisms underlying the reduced capability of hyperkinetic children to respond to rapidly delivered, repetitive stimuli are discussed.

Adult↗

PubMed1995

Beneficial effects of H290/51, a new lipid peroxidation inhibitor, on functional recovery after ischemia and reperfusion in isolated cold-arrested rat hearts.

Lipid peroxidation is one of the major mechanisms involved in free radical-mediated postischemic myocardial injury. In the present study, a newly synthetized lipid peroxidation inhibitor H290/51 [cis-7methyl-9-methoxy-5,5a,b,10b- tetrahydroindeno(2,1-6 indole)] was evaluated for its effects on myocardial functional recovery during reperfusion after 30-min global ischemia in isolated cold-arrested rat hearts. Administration of 200 and 800 nM H290/51 at initiation of global ischemia markedly improved the functional recovery, whereas 50 nM H290/51 had no significant effects. The percent recovery of cardiac output (CO), left ventricular developed pressure (LVDP), and LVdP/dtmax at the end of the 30-min reperfusion period in the working mode was much higher in the groups receiving 200 and 800 nM H290/51 than that in vehicle group (CO 73 +/- 5 and 60 +/- 5 vs. 23 +/- 7%; LVDP 79 +/- 5 and 73 +/- 8 vs. 43 +/- 10%; LV dP/dtmax 78 +/- 5 and 69 +/- 4 vs. 45 +/- 10%). The indenoindole compound H290/51 reduced ischemia/reperfusion-induced cardiac dysfunction.

Analysis of Variance↗

PubMed1985

Immediate functional recovery and avoidance of reperfusion injury with surgical revascularization of short-term coronary occlusion.

Functional recovery with surgical revascularization of acutely ischemic myocardium has not been compared with its nonsurgical counterpart in experimental preparations of coronary occlusion. This study compares the functional and metabolic recovery of ischemic (1 hr coronary occlusion) segments revascularized either by restoration of coronary patency (simulating nonsurgical recanalization, e.g., angioplasty) or by surgical revascularization with multidose hypothermic potassium blood cardioplegic solution. Twenty-two anesthetized open-chest dogs were instrumented with Millar micromanometer-tip catheters to measure left ventricular and aortic pressures. Piezoelectric ultrasonic dimension gauges were implanted in the subendocardium supplied by the left anterior descending coronary artery to measure segmental contractile function. In five dogs, only biopsy samples were obtained for control measurements of ATP, creatine phosphate, and tissue water content. In the remaining 17 dogs, the left anterior descending artery and collaterals were ligated for 1 hr. The ligatures were removed in eight dogs and coronary perfusion continued for 2 hr, simulating nonsurgical reperfusion. The remaining nine dogs were placed on cardiopulmonary bypass and the hearts were arrested for 1 hr with multidose (every 20 min) blood cardioplegic solution enhanced with glutamate and aspartate, simulating surgical revascularization (coronary artery bypass grafting). The coronary ligatures were not released until the second cardioplegic infusion, simulating graft placement. One hour of coronary occlusion placed 39.4 +/- 2.5% of the left ventricle at risk, and converted active systolic shortening to persistent paradoxical bulging (25.2 +/- 2.2% to -5.8 +/- 1.2% systolic shortening).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗

PubMed1990

Functional recovery after destruction of dopamine systems in the nucleus accumbens of rats. II. Facilitation by the ACTH-(4-9) analog ORG 2766.

Functional recovery from motor hypoactivity of rats with 6-OHDA lesions in the nucleus accumbens is accelerated by intra-accumbal or subcutaneous treatment with the ACTH-(4-9) analog ORG 2766. The spontaneous recovery period of 3 weeks is shortened to 7 days by daily treatment with this peptide during the first 6 days after the lesion. The 6-OHDA lesion induced a decrease of about 30-40% in the levels of dopamine, HVA and DOPAC as well as in the uptake of [3H]dopamine in nucleus accumbens tissue in vitro. Treatment with ORG 2766 during the first 6 days following the lesion did not affect the lesion-induced changes in these biochemical parameters. Binding studies with [3H]haloperidol in nucleus accumbens tissue of placebo or ORG 2766-treated sham-lesioned rats revealed a linear Scatchard plot 7 days after the sham lesion. In tissue of placebo-treated 6-OHDA lesioned animals a similar linear Scatchard plot was found but in tissue of ORG 2766-treated 6-OHDA-lesioned rats the Scatchard plot was curvilinear in shape indicating two types of binding sites. In the 6-OHDA-lesioned rats treated with ORG 2766 the behavioral response upon apomorphine challenge was enhanced suggesting the existence of functional supersensitivity of the DA system. Similar changes in Scatchard plots and apomorphine-induced behavioral changes have been previously reported after spontaneous recovery. The present study indicates that ORG 2766 accelerates the process of functional recovery from impaired motor behavior of rats with 6-OHDA lesions in the nucleus accumbens, which may be due to development of denervation supersensitivity.

Adrenocorticotropic Hormone↗

PubMed1983

Cerebral hemisphere asymmetry in CT and functional recovery from hemiplegia.

Cerebral hemispheric asymmetries were assessed in relation to motor and functional recovery in nine patients with stroke. All were globally aphasic, assuring similar location and extent of lesion. Initial motor and functional ability were appraised from medical records and compared with neurologic and functional outcome. Frontal and occipital hemispheric widths and lengths were determined from CT. Patients were classified into three groups on the basis of mean combined asymmetry for width (typical asymmetry, atypical asymmetry, and equal symmetry). Patients with the most atypical cerebral asymmetries showed greater recovery than patients in other groups. Two patients with atypical mean occipital asymmetry (width) fared best functionally, whereas the patient who showed the greatest motor recovery had the most atypical mean occipital asymmetry (width). Cerebral asymmetries may contribute to recovery after stroke.

Activities of Daily Living↗

PubMed1997

Simultaneous treatment with BDNF and CNTF after peripheral nerve transection and repair enhances rate of functional recovery compared with BDNF treatment alone.

The objective was to investigate the effects of brain-derived neurotropic factor (BDNF) and ciliary neurotropic factor (CNTF) on peripheral nerve regeneration. Thirty Sprague-Dawley rats underwent left sciatic nerve transection and repair according to three experimental groups: epineurial coaptation (EC), EC with BDNF delivered by an osmotic pump (EC-BDNF), and EC with BDNF and CNTF delivered similarly (EC-BDNF/CNTF). Nerve regeneration was assessed using sciatic functional indices, quantitative histomorphology, and molecular analysis for proteins associated with nerve regeneration. Analysis of variance (ANOVA) comparing all groups at each time point demonstrated significant differences between groups on days 20, 30, 40, 50, 60, and 80. A paired, two-tailed Student's t-test with the Bonferroni correction for multiple comparisons demonstrated that at 40 days postoperatively, animals in the EC-BDNF/CNTF group (n = 7) manifested superior functional recovery compared with those in the EC group (n = 9) and those in the EC-BDNF group (n = 9) (P < 0.001 and P < 0.05, respectively). At 80 days, the animals in both the EC-BDNF (P < 0.01) and EC-BDNF/CNTF (P < 0.05) groups demonstrated greater functional recovery compared with those in the EC group, with no significant difference between the two factor groups at the endpoint. Morphometric analysis demonstrated that nerves from animals in the EC-BDNF/CNTF group had the largest mean axon diameters as compared with those from the EC (proximal: P < 0.001, distal: P < 0.05) and EC-BDNF (proximal: P < 0.01) groups. No significant differences were seen in nerve cross-sectional area. In distal nerve segments, Western blot analysis revealed that expression of myelin-associated glycoprotein was higher than control for the EC group and lower than control for both the EC-BDNF and EC-BDNF/CNTF groups. We conclude that BDNF/CNTF combined treatment increases the early rate of functional sciatic nerve regeneration over treatment with BDNF alone, although the degree of maximal recovery was similar at the conclusion of the experiment.

Analysis of Variance↗

PubMed2026

Whole metagenome sequencing: not deep enough for complete microbial function recovery.

BACKGROUND: Whole metagenome shotgun sequencing (WMS) is widely used to profile microbial function. However, technical variability in sequencing and analysis often obscures true biological patterns. Large-scale studies are particularly susceptible to batch effects, such as differences in sequencing depth and platform and annotation strategies, as well as sample-to-flow-cell assignments. However, the relative effects of these factors on functional inference in such studies have yet to be systematically evaluated. We analyzed oral-rinse WMS data from 671 Nigerian youths aged 9-18, sequenced on two Illumina platforms. Microbial molecular functionality encoded in these data was annotated using the mi-faser/Fusion pipeline, to capture the broad functional repertoire, and HUMAnN 3/EC numbers pipeline to characterize curated enzymatic activities. We then quantified how technical factors and batch effects shaped the recovery of microbial functionality. RESULTS: Three findings of our work were most salient. First, we observed that the choice of annotation strategy traded off between breadth and specificity of functional coverage. Second, we found that low-prevalence functions were disproportionately lost at shallow sequencing depths, indicating that in, e.g., case-control studies with few representatives of the minor class, sequencing depth could critically impact study resolution. Finally, using our newly developed model relating sequencing depth to functional recovery, we demonstrated that increasing sequencing depth does not directly or proportionally improve functional recall. That is, at as little as 10% of this study's sequencing depth, 30% of the estimated complete microbiome functional repertoire was detectable. However, even at the full depth used in this study, we were only able to recover an estimated 60% of that complete functional repertoire. We further showed that despite biomes differences in functional diversity and host contamination levels (e.g., soil, fecal), incomplete functional recovery at commonly used sequencing depths was consistently observed. CONCLUSIONS: Together, these findings and our depth-to-function mapping framework provide practical guidelines for the design and interpretation of WMS studies. Coordinating sequencing depth planning with annotation strategy, experimental design, and rigorous batch control is thus essential for robust detection of microbial functions and for ensuring reproducible microbiome insights. Video Abstract.

Humans↗

PubMed1976

Rate and extent of functional recovery after flexor tendon grafting with and without silicone rod preparation.

Forty-six consecutive patients requiring flexor tendon grafts were evaluated at 4, 6, 8, 10, 12, 16, 20, 22, 24, 28, 34, and 52 weeks after grafting. The patients were divided into two groups: those who did not require a silicone rubber rod prior to tendon grafting (Group I), and those who did require a silicone rubber rod prior to grafting (Group II). Analysis of the rate of functional recovery as measured by total active motion, gross grip strength, and pinch grip strength showed no significant difference between the two groups. Analysis of the extent of functional recovery at one year, as measured by total active motion and distance of digital pulp from distal palmar crease, showed no significant differences between Groups I and II.

Adolescent↗

PubMed1991

Functional recovery of supersensitive dopamine receptors after intrastriatal grafts of fetal substantia nigra.

Interruption of the ascending dopamine neurons of the nigrostriatal pathway, by 6-hydroxydopamine (6-OHDA) lesion in rats, produced a significant loss of the dopamine transport complexes labeled with the phencyclidine derivative [3H]BTCP. This loss of dopamine innervation in the striatum was present at least 12 to 14 months after lesioning and was functionally manifested by ipsilateral rotation of the animals in response to amphetamine. In these same animals, in comparison to controls, there was a significant increase in the number (Bmax) of [3H]SCH 23390-labeled D-1 receptors in the striatum (36.7%) and the substantia nigra (35.1%) and a 54.4% increase in the number (Bmax) of [3H]sulpiride-labeled striatal D-2 receptors without an apparent change in affinity (Kd). Ten to twelve months after the transplantation of homologous fetal substantia nigra into the denervated striatum, there was a significant decrease in amphetamine-induced turning behavior. In these animals, there was an ingrowth of dopamine nerve terminals in the striatum as demonstrated by a return of [3H]BTCP binding. Accompanying this reinnervation was the normalization of D-1 and D-2 receptors to control values in the striatum as well as the return of D-1 receptors to prelesion densities in the substantia nigra. In a subgroup of transplanted rats, amphetamine continued to induce ipsilateral turning. In these animals both D-1 and D-2 receptors remained supersensitive. These results support the hypothesis that the functional recovery of transplanted animals is due, in part, to reinnervation of the striatum. In addition, long-term alterations in receptor density may be related to the behavioral deficits that are associated with the 6-OHDA-lesioned rat. Furthermore, dopamine receptor plasticity may play a role in the functional recovery of substantia nigra transplanted animals and graft viability seems to be a prerequisite for behavioral recovery as well as receptor normalization.

Acetylcholinesterase↗

PubMedDate not supplied

Auditory recovery function and P3 in boys at high risk for alcoholism.

We have previously reported P3 decrements in boys at risk for alcoholism in a complex visual rotation reaction time task. The present study investigated the generalizability of these observations by studying a new high risk sample of boys of Type 2 alcoholic fathers under different experimental conditions. The current experimental design consisted of an easy auditory oddball task (P3) which stressed accuracy over speed of responding, and which also included variable interstimulus intervals (0.5, 1.0 and 5.0 sec), allowing recovery functions to be derived from the evoked responses to frequent non-target stimuli. The results did not yield statistically significant differences between groups in the recovery function data. However the baseline-to-peak results to the target stimulus indicated significant decreases in both P2 and P3 amplitudes in the high risk boys. No differences in latency were obtained between groups. Furthermore frequency analysis of responses to the target stimulus using a multivariate time series model indicated between-group differences at 4 frequencies (1.43, 7.14, 8.6 and 11.43 Hz). These results replicate our previous findings of P3 decrements in boys at risk for alcoholism in a new sample of sons of Type 2 alcoholics. As we have now made these observations with different experimental conditions and sensory modalities, it is suggested that these findings are generalizable.

Adolescent↗