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PubMed1995

Comparison of myocardial contrast echocardiography and low-dose dobutamine stress echocardiography in predicting recovery of left ventricular function after coronary revascularization in chronic ischemic heart disease.

BACKGROUND: Dobutamine stress echocardiography (DSE) and myocardial contrast echocardiography (MCE) can predict recovery of left ventricular function after myocardial infarction. DSE also has been shown to predict left ventricular functional recovery after revascularization in chronic ischemic heart disease, whereas MCE has not been evaluated in such patients. This study was performed to compare DSE and MCE in the prediction of left ventricular functional recovery after revascularization in patients with chronic ischemic heart disease. METHODS AND RESULTS: MCE and DSE were performed in 35 patients with chronic coronary artery disease and significant wall motion abnormalities (mean ejection fraction, 0.36 +/- 0.09). Regional wall motion was scored by use of a 16-segment model wherein 1 = normal or hyperkinetic, 2 = hypokinetic, 3 = akinetic, and 4 = dyskinetic. Each segment was evaluated for contractile reserve by DSE and perfusion by MCE. Revascularization (coronary artery bypass graft [n = 13] and percutaneous transluminal coronary angioplasty [n = 10]) was successful in 23 patients. Follow-up echocardiograms were done to assess wall motion 30 to 60 days later. In 238 segments with resting wall motion abnormalities, perfusion was more likely to present than contractile reserve (97% versus 91%, P < .02). Revascularization resulted in functional recovery in 77 of 95 hypokinetic segments (81%) but only 18 of 57 akinetic segments (32%, P < .0001). DSE and MCE were not significantly different in predicting functional recovery of hypokinetic segments. In akinetic segments, DSE and MCE had similar sensitivities (89% versus 94%, respectively) and negative predictive values (93% and 97%, respectively) in predicting functional recovery. However, DSE had a higher specificity (92% versus 67%, P < .02) and positive predictive value (85% versus 55%, P < .02) than MCE in predicting functional recovery. CONCLUSIONS: Both contractile reserve by DSE and perfusion by MCE are predictive of functional recovery in hypokinetic segments after coronary revascularization in patients with chronic coronary revascularization in patients with chronic coronary artery disease. In akinetic segments, myocardial perfusion by MCE may exist in segments that do not recover contractile function after revascularization. Thus, contractile reserve during low-dose dobutamine infusion is a better predictor of functional recovery after revascularization in akinetic segments than perfusion.

Angioplasty, Balloon, Coronary↗

PubMed1995

Immediate-early gene induction and MAP kinase activation during recovery from metabolic inhibition in cultured cardiac myocytes.

To investigate how cardiac myocytes recover from a brief period of ischemia, we used a metabolic inhibition (MI) model, one of the in vitro ischemic models, of chick embryo ventricular myocytes, and examined the induction of immediate-early (IE) genes mRNAs and the activity of mitogen-activated protein (MAP) kinase. We performed Northern blot analysis to study the expression of c-jun, c-fos, and c-myc mRNAs during MI using 1 mM NaCN and 20 mM 2-deoxy-d-glucose, and also during the recovery from MI of 30 min. The c-fos mRNA was induced transiently at 30 and 60 min during the recovery. The expression of c-jun mRNA was significantly augmented at 30, 60, 90, and 120 min during the recovery (3.0-, 4.7-, 2.4-, and 1.9-fold induction, respectively) and so did the expression of c-myc mRNA (1.4-, 1.7-, 1.8-, and 2.0-fold induction, respectively). In contrast, the levels of these mRNAs remained unchanged during MI. The electrophoretic mobility shift assay revealed that AP-1 DNA binding activity markedly increased at 120 min during the recovery. When the cells were pretreated with protein kinase C (PKC) inhibitors, 100 microM H-7 or 1 microM staurosporine, the induction of c-jun mRNA at 60 min during the recovery was markedly suppressed (95 or 82% reduction, respectively). The c-jun induction was partially inhibited when the cells were treated with 2 mM EGTA during MI and the recovery (42% reduction). MAP kinase activity quantified with in-gel kinase assay was unchanged during MI, but significantly increased at 5, 10, and 15 min during the recovery (3.0-, 4.1-, and 3.4-fold increase, respectively). S6 kinase activity was also augmented significantly at 15 min during the recovery. Thus, these data suggest that IE genes as well as MAP kinase may play roles in the recovery process of cardiac myocytes from MI, and that the augmentation of c-jun expression needs the activation of PKC and to some extent, [Ca2+]i.

Animals↗

PubMed2004

Symptomatic and functional recovery from a first episode of schizophrenia or schizoaffective disorder.

OBJECTIVE: Follow-up studies have found that a substantial number of patients with schizophrenia achieve full recovery (i.e., sustained improvement in both symptoms and social/vocational functioning) when examined decades after an index admission. This study addressed recovery during the crucial early course of the illness. METHOD: Subjects in their first episode of schizophrenia or schizoaffective disorder (N=118) were assessed at baseline and then treated according to a medication algorithm. Full recovery required concurrent remission of positive and negative symptoms and adequate social/vocational functioning (fulfillment of age-appropriate role expectations, performance of daily living tasks without supervision, and engagement in social interactions). RESULTS: After 5 years, 47.2% (95% CI=36.0%-58.4%) of the subjects achieved symptom remission, and 25.5% (95% CI=16.1%-34.7%) had adequate social functioning for 2 years or more. Only 13.7% (95% CI=6.4%-20.9%) of subjects met full recovery criteria for 2 years or longer. Better cognitive functioning at stabilization was associated with full recovery, adequate social/vocational functioning, and symptom remission. Shorter duration of psychosis before study entry predicted both full recovery and symptom remission. More cerebral asymmetry was associated with full recovery and adequate social/vocational functioning; a schizoaffective diagnosis predicted symptom remission. CONCLUSIONS: Although some patients with first-episode schizophrenia can achieve sustained symptomatic and functional recovery, the overall rate of recovery during the early years of the illness is low.

Activities of Daily Living↗

PubMed2003

Role for c-Jun N-terminal kinase in beta-cell recovery from nitric oxide-mediated damage.

Treatment of rat islets with the cytokine IL-1 results in the inhibition of mitochondrial function and insulin secretion, events that are mediated by beta-cell expression of iNOS [inducible nitric oxide (NO) synthase] and production of NO. beta-Cells recover from the inhibitory actions of NO, produced following 24 h incubation with IL-1, on islet oxidative metabolism and insulin secretion if iNOS enzymatic activity is inhibited and the islets are cultured (in the presence of IL-1 and iNOS inhibitors) for a brief period of 8 h. Islet recovery from cytokine- and NO-mediated damage is an active process that requires new gene expression, and NO itself is one activator of this recovery process. In this study, the mechanism by which NO stimulates islet recovery has been examined. Incubation of rat islets or RINm5F cells with the NO donor compound, sodium (Z)-1(N,N-diethylamino) diazen-1-ium-1,2-diolate (DEA-NO) for 1 h results in a 60% inhibition of mitochondrial aconitase activity. beta-Cells completely recover aconitase activity if the cells are washed to remove the NO donor compound and incubated for an additional 5 h in the absence of DEA-NO. The recovery of mitochondrial aconitase activity correlates with a 4-fold increase in cyclic GMP accumulation and is prevented by the inhibition of guanylate cyclase. The recovery of aconitase activity also correlates with the activation of members of the MAPKs, p38, c-Jun N-terminal kinase (JNK) and ERK, and the activation p38 and JNK is attenuated by inhibition of guanylate cyclase. ERK and p38 do not appear to participate in the recovery process as selective inhibition of these kinases fails to prevent recovery of aconitase activity; however, transduction of beta-cells with a dominant negative mutant JNK prevents beta-cell recovery from NO-mediated damage. These findings support a role for guanylate cyclase and JNK in the recovery of beta-cells from NO-mediated damage.

Aconitate Hydratase↗

PubMed2006

Contractile recovery from acidosis in toad ventricle is independent of intracellular pH and relies upon Ca2+ influx.

Hypercapnic acidosis produces a negative inotropic effect on myocardial contractility followed by a partial recovery that occurs in spite of the persistent extracellular acidosis. The underlying mechanisms of this recovery are far from understood, especially in those species in which excitation-contraction coupling differs from that of the mammalian heart. The main goal of the present experiments was to obtain a better understanding of these mechanisms in the toad heart. Hypercapnic acidosis, induced by switching from a bicarbonate-buffered solution equilibrated with 5% CO2 to the same solution equilibrated with 12% CO2, evoked a decrease in contractility followed by a recovery that reached values higher than controls after 30 min of continued acidosis. This contractile pattern was associated with an initial decrease in intracellular pH (pHi) that recovered to control values in spite of the persistent extracellular acidosis. Blockade of the Na+/H+ exchanger (NHE) with cariporide (5 micromol l-1) produced a complete inhibition of pHi restitution, without affecting the mechanical recovery. Hypercapnic acidosis also produced a gradual increase of diastolic and peak Ca2+i transient values, which occurred immediately after the acidosis was settled and persisted during the mechanical recovery phase. Inhibition of Ca2+ influx through the reverse mode of the Na+/Ca2+ exchanger (NCX) by KB-R (1 micromol l-1 for myocytes and 20 micromol l-1 for ventricular strips), or of L-type Ca2+ channels by nifedipine (0.5 micromol l-1), completely abolished the mechanical recovery. Acidosis also produced an increase in the action potential duration. This prolongation persisted throughout the acidosis period. Our results show that in toad ventricular myocardium, acidosis produces a decrease in contractility, due to a decrease in Ca2+ myofilament responsiveness, followed by a contractile recovery, which is independent of pHi recovery and relies on an increase in the influx of Ca2+. The results further indicate that both the reverse mode NCX and the L-type Ca2+ channels, appear to be involved in the increase in intracellular Ca2+ concentration that mediates the contractile recovery from acidosis.

Acidosis↗

PubMed2001

Recovery periods restore mechanosensitivity to dynamically loaded bone.

Bone cells are capable of sensing and responding to mechanical forces, but mechanosensitivity begins to decline soon after the stimulus is initiated. Under continued stimulation, bone is desensitized to mechanical stimuli. We sought to determine the amount of time required to restore mechanosensitivity to desensitized bone cells in vivo by manipulating the recovery time (0, 0.5, 1, 2, 4 or 8 h) allowed between four identical daily loading bouts. We also investigated the osteogenic effectiveness of shorter-term recovery periods, lasting several seconds (0.5, 3.5, 7 or 14 s), introduced between each of 36 identical daily loading cycles. Using the rat tibia four-point bending model, the right tibia of 144 adult female Sprague-Dawley rats was subjected to bending, sham bending or no loading. In the rats receiving recovery periods between loading bouts, histomorphometric measurements from the endocortical surface of the loaded and nonloaded control (left) tibiae revealed more than 100 % higher relative bone formation rates in the 8 h recovery group than in the 0 and 0.5 h recovery groups. Approximately 8 h of recovery was sufficient to restore full mechanosensitivity to the cells. In the rats allowed time to recover between load cycles, 14 s of recovery resulted in significantly higher (66-190 %) relative bone formation rates compared to any of the three shorter recovery periods. In both experiments, bone formation in the sham-bending animals was similar to that in the nonloaded control group. The results demonstrate the importance of recovery periods for (i) restoring mechanosensitivity to bone cells and (ii) maximizing the osteogenic effects of mechanical loading (exercise) regimens.

Animals↗

PubMed2000

Effects of 'cool-down' during exercise recovery on cardiopulmonary systems in patients with coronary artery disease.

The effects of 'cool-down' during exercise recovery on cardiovascular and respiratory systems have not been fully clarified. The recovery of respiratory gasses was compared in cardiac patients after maximal exercise during which subjects either performed a cool-down or rested. Twenty-one patients (61+/-10 years) with coronary artery disease performed 2 symptom-limited incremental exercise tests on a cycle ergometer: one with a cool-down and the other without during recovery from the maximal exercise test. Expired gasses were analyzed on a breath-by-breath basis throughout the test and for 6min of recovery. Without a cool-down, the ventilatory equivalent for O2 (VE/O2) increased dramatically during recovery compared with the resting values or those of peak exercise: 44.5+/-7.7 at rest, 44.0+/-10.6 at peak exercise and 63.3+/-14.5 after 2min of recovery. End-tidal PO2 (P(ET)O2) also increased significantly during recovery. However, the overshoot phenomenon of these variables was attenuated when cool-down exercise was performed during recovery. The high ratio of VE/VO2 reflects ventilation perfusion (VA/Q) unevenness and P(ET)O2 is an index of arterial PO2. Thus, it is suggested that cool-down exercise during recovery after maximal exercise testing provides beneficial effects on the respiratory system by decreasing the VA/Q unevenness and relative hyperventilation that are observed when cool-down exercise is not performed.

Adult↗

PubMed1996

Influence of oestrous cycle on the pressor recovery following haemorrhage in anaesthetized Brattleboro rats.

A sexual dimorphism in the pressor responsiveness to the neurohypophysial hormone vasopressin may be associated with a peripheral interaction between ovarian steroids and the neurohypophysial hormone. Indeed, the ovarian steroids may inhibit the vasopressin-dependent component of the pressor response to haemorrhage. The present study examined the recovery of the arterial blood pressure following it single large (2% v/w) haemorrhage in anaesthetized male Long Evans (LE) rats and females of the same strain during either pro-oestrous or di-oestrous phases of the reproductive cycle. In addition the same recovery process was examined in Brattleboro rats with diabetes insipidus (BDI) lacking circulating vasopressin. All BDI rats had an impaired blood pressure recovery following haemorrhage compared with male rats of the parent LE strain, and this was irrespective of sex or stage of the oestrous cycle. While the blood pressure recovery was more impaired in both groups of BDI female rats than in the males of the same strain during the first 20 min after haemorrhage (both comparisons p < 0.001; ANOVA), there was no difference between the recoveries of the female rats in pro-oestrus or di-oestrus. In contrast a significantly impaired blood pressure recovery was observed in female LE rats at pro-oestrus, when circulating ovarian steroid concentrations are raised, compared with male (p < 0.001: ANOVA) and di-oestrous (p < 0.02: ANOVA) rats of the same strain. Heart rate responses to haemorrhage showed strain differences, with LE rats having initial decreased heart rates followed by a recovery process, while the heart rate responses of BDI rats increased immediately. The novel use of the female Brattleboro rat in this study provides evidence for the existence of an important inhibitory interaction between ovarian steroids and vasopressin during the blood pressure recovery phase following haemorrhage, and indicates a possible direct influence of gonadal steroids on the recovery process.

Animals↗

PubMed1989

Fertilization and ovum recovery rates in superovulated ewes following cervical insemination or laparoscopic intrauterine insemination at different times after progestagen withdrawal and in one or both uterine horns.

In Exp. 1, 40 ewes were used in a 2 x 2 factorial design to investigate the effects of intrauterine versus cervical insemination and superovulation using pig FSH or PMSG and GnRH on egg recovery and fertilization rate. Cervical inseminations were carried out at 48 and 60 h (N = 20 ewes) and intrauterine insemination at 52 h (N = 20 ewes) after progestagen pessary withdrawal. Eggs were recovered on Day 3 of the oestrous cycle. Ovulation, egg recovery and fertilization rates were independent of the type of superovulatory hormone used. Fertilization rate was high irrespective of insemination site but intrauterine insemination at 52 h was associated with a significant (P less than 0.01) decrease in egg recovery of over 40% compared with cervically inseminated ewes. In Exp. 2 ewes were inseminated at 36 (N = 5), 48 (N = 6) or 60 (N = 6) h after pessary withdrawal to determine the optimum intrauterine insemination time to maximize both fertilization rate and egg recovery. Egg recovery per ewe flushed was 23, 59 and 67% after intrauterine insemination at 36, 48 and 60 h respectively. Correspondingly, 0, 85 and 100% of the eggs recovered were fertilized. The results of Exps 1 and 2 suggest that when intrauterine insemination occurs before or during ovulation it interferes with oocyte collection by the fimbria. In Exp. 3 egg recovery and fertilization rates were determined after cervical insemination at 48 and 60 h (N = 8) or intrauterine insemination at 48 (N = 9) or 60 (N = 8) h after progestagen withdrawal. Ewes in the last two groups were subdivided and inseminated unilaterally or bilaterally. Egg recovery was high after cervical insemination (95%) but only 36% of these eggs were fertilized. Unilateral intrauterine insemination was as effective as bilateral in ensuring high fertilization rates (100 versus 97%). Intrauterine insemination at 48 h compared with 60 h resulted in a significantly lower (P less than 0.05) percentage of eggs recovered (42 versus 90% respectively). However, reducing the degree of interference by adopting unilateral rather than bilateral insemination did not alleviate the detrimental effects of the 48-h insemination time on egg recovery. From these results we advocate the adoption of intrauterine insemination at 60 h after progestagen withdrawal to maximize fertilization rate and egg recovery in superovulated ewes.

Animals↗

PubMed2006

Overtime and need for recovery in relation to job demands and job control.

This study addressed the prevalence of working overtime in relation to psychosocial work characteristics and need for recovery. More precisely, the aim of this study was to find out (1) whether a relationship exists between working overtime and psychosocial work characteristics (job demands and job control), (2a) whether a relationship exists between working overtime and need for recovery, and finally (2b) whether such a relationship depends on job type (a specific combination of job demands and job control). The study sample (N=1,473) consisted of a national random sample of office-based municipal administration employees who worked full-time. These employees completed a questionnaire on working conditions, overtime and need for recovery, among other things. Overtime was especially common in jobs characterised by high demands. The analyses showed that working overtime is not associated with a higher need for recovery in the total study population. However, there was a positive relationship between overtime hours and need for recovery in high strain jobs (high demands, low control). Furthermore, there was a positive relationship between structural overtime and need for recovery in active jobs (high demands, high control). The relationship between overtime and need for recovery seems to be dependent upon working conditions; indicators of overtime were associated with a higher need for recovery only for employees who experienced high job demands. Longitudinal research within a heterogeneous sample will be necessary to draw firm conclusions about causality with respect to the relationship between overtime, need for recovery and working conditions.

Adult↗

PubMed1999

Relationship between aging and recovery of the underlying mucosa immediately after removal of pressure: the first molar region in the mandible.

To investigate changes in the characteristics of edentulous mucosa in the alveolar ridge with aging, we applied pressure to the mucosa of the alveolar ridge in subjects of various ages and evaluated the recovery amount and time after the pressure was removed. Twenty-three subjects ranging from 23 to 79 years of age, who had lost the first mandibular molar tooth, were selected. Displacing pressure was applied to the mucosa corresponding to the mandibular first molar region. After release the pressure, we measured the recovery amount of mucosa from its displacement, which was expressed as the movement of a target which had been placed on the mucosa as measured by an indirect displacement measurement device. The levels of displacement were set at 0.1 mm, 0.2 mm and 0.3 mm, and the time to achieve the selected displacement level was set at 1 second. The initial recovery of the mucosa immediately after the pressure has been released was designated as the initial recovery amount, and the time needed for recovering to 90% of the previous state was designated as the final recovery time. Then we investigated the relationships between the measures of the initial recovery amount, the final recovery time, and the subjects' ages. The initial recovery amount of mucosa was lower and the final recovery time was longer in older subjects, and this tendency was exaggerated when the displacement was increased.

Adult↗

PubMed2002

Association of fasting plasma glucose with heart rate recovery in healthy adults: a population-based study.

Diabetes is associated with abnormal autonomic function and increased mortality. Abnormal heart rate recovery after exercise, a measure of autonomic dysfunction, is also associated with increased mortality. The objective of this study was to determine the association of fasting plasma glucose with abnormal heart rate recovery and its prognostic importance in healthy adults. We studied 5,190 healthy adults who did not have medically treated diabetes (mean age 45 years, 39% women), were enrolled in the Lipid Research Clinics' Prevalence Study, and underwent exercise testing. Heart rate recovery was defined as the change from peak heart rate to that after 2 min of recovery; an abnormal value was < or = 42 bpm. All-cause mortality was assessed over 12 years. A total of 504 participants (10%) had impaired fasting glucose, and 131 (3%) had untreated diabetes. An abnormal heart rate recovery was found in 1,699 (33%). Compared with participants who had normal fasting plasma glucose, abnormal heart rate recovery was more common among those with impaired fasting glucose (42 vs. 31%; relative risk, 1.34; 95% confidence interval [CI], 1.20--1.50; P < 0.0001) and those with diabetes (50 vs. 31%; relative risk, 1.61; 95% CI, 1.35--1.92; P < 0.0001). Fasting plasma glucose remained an independent predictor of abnormal heart rate recovery even after adjustment for age, sex, and other confounders (P = 0.0003). An abnormal heart rate recovery added to impaired fasting plasma glucose for the prediction of death. Fasting plasma glucose is strongly and independently associated with abnormal heart rate recovery, even at nondiabetic levels.

Adult↗

PubMed1994

Evaluation of hearing recovery in patients with sudden deafness.

It is still difficult to evaluate the efficacy of treatment of sudden deafness. Effective methods of therapy have been reported in some studies and other studies have reported spontaneous recovery. In the present study, we assessed the correlation between hearing recovery and various parameters measured during recovery. We used three parameters: hearing gain, relative hearing gain, and recovery rate. We found that the recovery rate during recovery and the parameters measured on the 7th treatment day demonstrated the greatest correlation. The recovery rate on the 7th day of treatment was found to be useful for predicting the final hearing recovery. Comparison of the recovery rate on the 7th day of treatment may be useful for the evaluation of the efficacy of treatment of sudden deafness.

Adenosine Triphosphate↗

PubMedDate not supplied

Modification of recovery from radiation damage by hyperthermia in yeast.

Recovery from radiation damage was studied in the diploid yeast Saccharomyces cerevisiae BZ 34 subjected to pre-irradiation, post-irradiation or simultaneous hyperthermic treatment. Pre-irradiation heat treatment at 51 degrees C for 20 m min sensitized the cells to lethal damage; however, these cells could efficiently recover from potentially lethal damage (PLD) on liquid holding. In contrast, post-irradiation hyperthermia (51 degrees C for 20 min or 52 degrees C for 15 min) partially inhibited recovery from PLD. For treatments at 40 and 45 degrees C the inhibition of recovery was restricted to the duration of heat treatment. As soon as the temperature of the cells was reduced to 30 degrees C for 48 h, they showed a significant recovery from PLD. The kinetics of the liquid holding recovery of cells exposed to 600 and 900 Gy of radiation followed by heat treatment at 51 degrees C, 20 min or 52 degrees C, 15 min was studied. Post-irradiation heat treatment inhibits PLD repair (PLDR) during the first 3 h. Subsequent liquid holding for longer durations results in recovery from PLD, reaching a maximum of nearly 50% of that obtained in cells exposed to radiation alone. When the cells were held for 0-48 h between radiation and heat treatment, they showed recovery from radiation damage such that sensitization by subsequent heat treatment was reduced significantly over the 48 h interval. The inhibition of PLDR by hyperthermia also decreases progressively with an increase in the time interval between the two treatments. When both heat and radiation treatments were carried out simultaneously by irradiating the cells at 48 degrees C, the inhibition of PLDR was partial. The recovery factor, calculated as the ratio of survival after recovery to that on immediate plating (without PLDR), was 2.6 +/- 0.9 for simultaneous heat and radiation treatment compared to 11.9 +/- 2.7 for radiation alone.

Cell Survival↗

PubMed1996

Patterns of hearing recovery in idiopathic sudden sensorineural hearing loss.

Patterns of hearing recovery in idiopathic sudden sensorineural hearing loss (ISSNHL) during the initial stage of treatment were examined in 51 patients who showed significant recovery. By plotting average hearing threshold level or degree of average hearing improvement against number of days after the first examination, a pattern of recovery was seen for each patient, and the superimposed patterns of hearing recovery were examined as a whole and in groups. The results indicated that most patients showed either initial rapid recovery reaching a plateau or a very gradual and slow recovery. In a small number of patients, the pattern of rapid recovery appeared somewhat delayed. Further analysis by grouping the patients revealed that initial rapid recovery was frequently observed in the groups which showed smaller degree of hearing loss at the first examination, greater degree of hearing improvement overall, and smaller degree of hearing loss once stable. The results of this study appear to indicate that patterns of recovery at the initial stage of ISSNHL reflect the prognosis to a certain degree.

Adolescent↗

PubMed2006

[Effect of dialysis time in vivo on recovery of amino acids for micro-dialysis probe].

OBJECTIVE: To investigate the variety of vitro recovery of amino acids for microdialysis probe after different dialysis time in vivo. METHODS: Probes were dialyzed in the amino acids standard solutions with microdialysis system,amino acid standard solutions and the microdialysate of probe were detected by the method of precolumn derivation with HPLC-RF. RESULT: After using different time of probe made by regenerated cellulose membrane, the vitro recoveries of Asp, Glu and GABA were not completely same (Asp: F=19.669, P=0.000; Glu: F=103.955, P=0.000; GABA: F=3.454, P=0.040); while the vitro recovery of Tau had no obvious difference(F=2.001, P=0.152). After using 6 h in vivo, recovery remain percentage (RRP) of Asp, Glu,Tau and GABA was 64.34 %, 67.36%, 103.11 % and 98.23 %, respectively, the recoveries of Asp, Glu decreased obviously (Asp: P < 0.01,Glu: P <0.05). After using 12 h in vivo, the RRP of Asp, Glu, Tau and GABA was 43.44 %, 24.42%, 77.45 % and 67.36 %, respectively, the recoveries of Asp, Glu and GABA decreased obviously (Asp: P < 0.001, Glu: P < 0.001, GABA: P < 0.05). After using 24 h in vivo, the RRP of Asp, Glu,Tau and GABA was 36.26 %, 12.24 %, 89.48 % and 71.35 %, respectively, the recoveries of Asp, Glu, GABA decreased obviously (Asp: P < 0.0001, Glu: P < 0.0001, GABA: P < 0.01). CONCLUSION: Dialysis in vivo could lead to the decline of recovery of probe, the decline is more obvious after longer dialysis. So when making brain dialysis experiments, the use time of probe should not be too long. To improve the validity of data, some calibration should be made on the recoveries of probe.

Amino Acids↗

PubMed2000

Determinants of the acetate recovery factor: implications for estimation of [13C]substrate oxidation.

When using (13)C or (14)C tracers to study substrate metabolism, an acetate correction factor should be applied to correct for loss of label in the exchange pathways of the tricarboxylic acid cycle. We have shown recently that the [(13)C]acetate recovery factor has a high inter-individual variability and should therefore be determined in every subject. In the present study we examined the factors that might explain some of the variability between subjects in acetate recovery factor. Data were pooled from four different studies with identical protocols, in which the acetate recovery factor was measured, prior to an intervention, to correct plasma fatty acid oxidation rates. Acetate recovery was measured after 2 h of [1, 2-(13)C]acetate infusion at rest followed by 1 h of cycling exercise at 40-50% of maximal oxygen uptake. Inter-individual variance in acetate recovery was 12.0% at rest and 16.1% during exercise. Stepwise regression revealed that, at rest, 37.1% of the acetate recovery could be accounted for by basal metabolic rate adjusted for fat-free mass, percentage body fat and respiratory quotient (RQ). During exercise, 69.1% of the variance in acetate recovery could be accounted for by energy expenditure adjusted for fat-free mass, % body fat and RQ. In conclusion, we show that the acetate recovery factor has a high inter-individual variability, both at rest and during exercise, which can partly be accounted for by metabolic rate, RQ and % body fat. These data indicate that the acetate recovery factor needs to be determined in every subject, under similar conditions as used for the tracer-derived determination of substrate oxidation. Failure to do this might result in large under- or over-estimation of plasma substrate oxidation, and hence to artificial differences between groups.

Acetic Acid↗

PubMed2002

Recombinant factor IX recovery and inhibitor safety: a Canadian post-licensure surveillance study.

As part of the Canadian post-licensure surveillance on the safety of recombinant factor IX (rFIX. BeneFIX), factor IX recovery and inhibitor development were studied. The recovery following rFIX infusion in 126 patients (mean = 0.77, median 0.72, range 0.36-1.85, 95% CI of mean 0.74-0.81, expressed as FIX activity increase in U/dL per IU FIX concentrate/kg body weight infused) was significantly lower than that following the last plasma-derived factor IX (pdFIX) infusion in 74 patients (mean 1.05, median 1.00, range 0.37-2.29, 95% CI of mean 0.99-0.97). The recovery for rFIX for patients aged < or =15 years (n = 41, mean recovery 0.64) and that for patients aged >15 years (n = 85, mean 0.84) was each significantly lower than that for pdFIX (aged < or =15 years: n = 21, mean recovery 0.91; aged >15 years: n = 53, mean recovery 1.10). For both rFIX and pdFIX concentrates, the recovery was lower in patients < or =15 years of age compared to those > 15 years of age. Similar data and conclusions were obtained on 66 patients with paired recovery data from rFIX and pdFIX. Overall, our data are similar to those obtained in formal clinical trials. Two of 244 patients treated with rFIX for up to 5 years have developed de novo inhibitors associated with anaphylaxis, an incidence that is similar to that reported for pdFIX. No other serious adverse events, including thrombotic episodes, were reported. To the best of our knowledge, this is the first formal report of recovery and inhibitor formation on rFIX in a peer-reviewed manuscript form.

Adolescent↗