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Listening to injured workers: how recovery expectations predict outcomes--a prospective study.

BACKGROUND: Rigorous evidence on factors affecting the prognosis of work-related soft-tissue injuries remains limited. Although shown to be important for a wide variety of clinical conditions, recovery expectations have rarely been assessed as prognostic factors for workers with soft-tissue injuries. We examined the predictive role of various measures of recovery expectations among workers with injuries resulting in time off work. METHODS: We identified a prospective cohort of 1566 injured workers shortly after they filed a claim for their injury with the Ontario Workers' Compensation Board (OWCB). They had soft-tissue injuries to the back or upper or lower extremities, had new, lost-time claims from May to November 1993 and were still off work at the time of the first interview. We interviewed participants by telephone within 3 weeks after the injury and measured their recovery expectations (perceptions regarding progress, expected change in condition, expected time until return to usual activities and expectations regarding return to usual job) along with other, potentially important prognostic factors. The primary outcome was total time receiving 100% wage-replacement benefits during the year following injury, obtained from OWCB administrative files. Self-reported measures of pain, health-related quality of life and functional status, obtained up to 4 times during the year following injury, were both independent predictors and secondary outcomes. RESULTS: The 4 measures of recovery expectations together explained one-sixth of the variation in time receiving benefits. All but expectations regarding return to usual job were individually predictive of time receiving benefits. Judging one's recovery as much better than expected resulted in a 30% (95% confidence interval [CI] 9%-46%) faster rate of stopping receiving benefits (and likely returning to work) compared with judging one's recovery as much worse than expected. Similarly, participants who expected to return to usual activities within 3 weeks had a 37% (95% CI 26%-47%) faster rate of stopping receiving benefits than those who responded "Don't know" to this question, and participants who stated that they were fully recovered or would get better soon had a 25% (CI 5%-40%) faster rate than those who thought they would never get or stay better. Positive recovery expectations were also associated with reductions in pain grade and improvement in functional status outcomes. INTERPRETATION: Expectations regarding recovery may provide useful information on the complex process of recovering from work-related soft-tissue injuries. For clinicians, patients' negative or uncertain expectations may indicate the need for further probing and intervention on psychosocial factors to facilitate recovery.

Adult↗

Dutch analysis for P-recovery from municipal wastewater.

There is a considerable practical interest in phosphorus recovery from water authorities, elementary P-industry, fertilizer industry and regulators in a number of countries. Due to a handful of full-scale plants worldwide, P-recovery can be seen as technically feasible. However, the economic feasibility of P-recovery from sewage can still be judged as dubious. The most important reason for this is that the prices of the techniques (in euro/tonne P) are much higher compared to the prices of phosphate rock. In this paper an analysis is given to recover phosphate from municipal wastewater for the elementary P-industry Thermphos International B.V. and the fertiliser industry Amsterdam Fertilizers B.V. in The Netherlands. Several scenarios are evaluated and the end products of these scenarios are compared to the quality required by both industries. From a Dutch study it became clear that all end products from the final sludge treatment do not provide a good source of secondary phosphate. As a consequence of this, the most preferred possibility for P-recovery is to extract phosphate before sludge goes to the final sludge treatment. Different scenarios can be selected based on the position of P-recovery in the WWTP configuration, the type of P-recovery product, and the precipitation technique. Local conditions will determine which scenario is the most expedient. Because it is more realistic to judge a practical situation instead of theoretical estimations based on literature, some local situations have to be assessed in sufficient detail to gain more feeling for the expenses and possible savings of P-recovery. One important actor that should be involved in the process management around P-recovery, is the national government. Especially, the Government have the responsibility for sustainable development and should have attention for some stimulation of P-recovery in The Netherlands. Water authorities and the P- and fertilizer industry made already some good steps.

Agriculture↗

[Real time myocardial contrast echocardiography to predict left ventricular wall motion recovery after reperfused acute myocardial infarction].

INTRODUCTION AND OBJECTIVES: Real time myocardial contrast echocardiography (RTMCE) is a recently developed method. We sought to determine: a) whether RTMCE predicts recovery of left ventricular function after acute myocardial infarction (AMI), and b) whether data obtained with this method are comparable to those obtained with 99mTc-sestamibi single photon emission computed tomography (SPECT) and magnetic resonance. PATIENTS AND METHOD: We studied 85 patients with AMI who underwent angioplasty. RTMCE was performed 7 (4) days after AMI. Two-dimensional echocardiography was performed at the time of the RTMCE study and at follow-up (10 [4] weeks). SPECT and magnetic resonance were performed after AMI in 18 and 32 patients, respectively. RESULTS: Follow-up two-dimensional echocardiography results were available for 82 patients, who were subdivided into 2 groups: recovery (n=49) and no recovery (n=33). Regional (AMI-related) wall motion score index improved from 1.75 (0.49) to 1.32 (0.36) (P< .001) in the recovery group, and worsened from 1.85 (0.39) to 1.95 (0.36) in the no recovery group (P< .001). RTMCE perfusion score was 0.8 (0.3) in the recovery group, and 0.6 (0.4) in the no recovery group (P< .001). Concordance between RTMCE and SPECT in a segmental analysis was 78% (P< .001; kappa=0.49), whereas concordance between RTMCE and hyperenhancement with delayed contrast magnetic resonance findings was 70% (P< .001; kappa =0.35). Independent predictors of recovery were peak creatine kinase (OR=1.4 per 1000 UI; 95% CI, 1.0-1.9; P< .05) and RTMCE score (OR=8.8; 95% CI, 1.9-39.3; P< .01). A RTMCE score > or = 0.60 had a positive predictive value of 73% and a negative predictive value of 69% (P< .001; area under the curve 0.70). CONCLUSION: RTMCE showed a modest predictive value for recovery of left ventricular function after reperfused AMI.

Angioplasty, Balloon, Coronary↗

Recovery of renal function in continuous ambulatory peritoneal dialysis: a study of National CAPD Registry data.

From January 1981 to July 1988, the U.S. National CAPD Registry followed 23,771 patients on CAPD or CCPD for 3 months or more in 498 participating centers. Of these patients, 281 were deemed to have enough recovery of renal function to do without dialysis for at least 3 months. The median time on PD before recovery was 126 days in 138 patients treated only by PD from the start of dialysis. The median time to recovery in 106 patients was 238 days from the start of any chronic dialysis. A Cox model analysis revealed significantly (p less than 0.05) increased chances for renal function recovery in patients with systemic immunological diseases with renal involvement (relative risk for recovery [rr] = 2.48), patients with renal infarction related to renal vascular occlusion (rr = 4.13), and patients greater than 60 years of age compared to a younger group (rr = 1.72). However, patients greater than 60 and less than 21 experienced similar recovery rates. Reduced chances (p less than 0.05) for recovery were associated with diabetic glomerulosclerosis (rr = 0.25) and polycystic kidney disease (rr = 0.13). These findings show that renal function recovery rates in chronic hemodialysis and chronic peritoneal dialysis cannot be properly compared unless all risk factors (favoring or against recovery) are balanced, as in a prospective randomized trial.

Adult↗

Synergy between recombinant human IL-1 alpha (rHuIL-1) and M-CSF (rHuM-CSF) during the recovery of murine hematopoietic activity in myelosuppressed animals: abbreviated versus chronic administration of rHuM-CSF.

The ability of highly purified, recombinant human macrophage colony-stimulating factor (M-CSF) and recombinant human interleukin 1 alpha (IL-1) to rescue hematopoietic activity from the myelosuppressive effects of 5-fluorouracil (5-FU) was investigated in the C57Bl/6 mouse. IL-1 (q24 h x 4) stimulated granulopoietic recovery in the 5-FU-treated animals and reduced the period of severe neutropenia associated with this drug by 7 days. Chronic M-CSF administration (q24 h x 14), on the other hand, resulted in a modest retardation of granulocyte recovery, and, when combined with IL-1, the chronic administration of M-CSF significantly dampened the accelerated recovery of granulopoietic activity observed with IL-1 alone. Consistent with their effects on neutrophil recovery, IL-1 alone markedly enhanced the recovery of the granulocyte erythrocyte macrophage megakaryocyte colony-forming units (CFU-GEMM), macrophage colony-forming units (CFU-M), and erythroid burst-forming units (BFUe) in the marrow, whereas M-CSF failed to demonstrate a significant influence on the restoration of these hematopoietic progenitors (with the exception of delaying the recovery of the BFUe). Unexpectedly, the combination of IL-1 plus M-CSF (q24 h, days 1-4) followed by M-CSF (q24 h, days 5-14) resulted in a more than additive stimulation of progenitor recovery in both the marrow and the spleen that was observed as early as day 3 following 5-FU treatment. Furthermore, in the absence of protracted M-CSF administration on days 5-14, the 4-day rescue with a combination of IL-1 plus M-CSF also resulted in a more than additive effect on the recovery from 5-FU-induced neutropenia. Collectively, these observations demonstrated that IL-1 and M-CSF can interact synergistically to stimulate granulopoietic recovery in the 5-FU-treated animal. However, the data also suggest that the continued administration of M-CSF following the 4-day IL-1 plus M-CSF rescue may interfere with the restoration of neutrophils in the myelosuppressed animal.

Animals↗

Recovery of neuromuscular function after a combination of mivacurium and rocuronium.

PURPOSE: The present study was undertaken to evaluate onset, and early and late recovery of neuromuscular block after a combination of mivacurium (M) and rocuronium (R). METHODS: In this controlled, randomized study, 45 consenting ASA I-II patients were assigned to one of three treatment groups: 2.ED95 R alone (2R); 2.ED95 R plus 1.ED95 M (2R1M). or 2.ED95 R plus 2.ED95 M (2R2M). Neuromuscular monitoring of the ulnar nerve consisted of surface electrode stimulation and force transduction of the adductor pollicis muscle. Stable baseline stimulation (1 Hz, square-wave, supramaximal current) was established prior to relaxant administration and continued until 95 percent twitch height depression (onset). Thereafter, train-of-four stimulation every 10 seconds was used to record recovery data until 95 percent recovery (T(95%)). Data were analyzed using grouped t-tests, ANOVA, and Newman-Keuls multiple comparison tests. Significance was defined at the p < 0.05 level. RESULTS: The addition of mivacurium to rocuronium did not accelerate onset of block. The combination prolonged the clinical duration (time to 5 percent recovery, T(5%)), but did not affect subsequent recovery parameters: T(5%) in the 2R1M and 2R2M groups were 100 percent and 118 percent longer than in the 2R group, respectively (p < 0.05) the T(5-25%) (early recovery) and T(25-75%) (linear recovery) indexes were similar in all three groups. CONCLUSIONS: The present study did not note an acceleration of block onset when mivacurium was added to rocuronium. The findings suggest that the addition of mivacurium (1-2.ED95) to rocuronium (2.ED95) prolongs the clinical duration of the longer-acting agent, rocuronium, but has no effect on the early or linear recovery indexes of rocuronium. Thus, although clinical duration is prolonged, recovery from the combination regimens proceeds as if no mivacurium had been added to rocuronium.

Adolescent↗

The role of monitored natural recovery in sediment remediation.

The long-term goal of monitored natural recovery (MNR) is to achieve ecological recovery of biological endpoints in order to protect human and ecological health. Insofar as ecological recovery is affected by surface-sediment-contaminant concentrations, the primary recovery processes for MNR are natural sediment burial and contaminant transformation and weathering to less toxic forms. This paper discusses the overall approach for effective implementation of MNR for contaminated sediment sites. Several lines of evidence that may be used to demonstrate natural recovery processes are summarized, including documentation of source control; evidence of contaminant burial; measurement of surface sediment mixing depths and the active sediment benthic layer; measurement of sediment stability; contaminant transformation and weathering; modeling sediment transport, contaminant transport, and ecological recovery; measuring ecological recovery and long-term risk reduction; knowledge of future plans for use and development of the site; and watershed and institutional controls. In general, some form of natural recovery is expected and should be included as part of a remedy at virtually all contaminated sediment sites. Further, MNR investigations and an understanding of natural recovery processes provide cost-effective information and support the evaluation of more aggressive remedies such as capping, dredging, and the use of novel amendments. The risk of dredging or capping may be greater than the risk of leaving sediments in place at sites where capping or dredging offer little long-term environmental gain but pose significant short-term risks for workers, local communities, and the environment.

Ecology↗

Effects of active and passive recovery on lactate removal and subsequent isokinetic muscle function.

The effect of active and passive recovery on the removal of accumulated blood lactate and subsequent muscle function were tested using five male subjects. The experimental protocol consisted of two exercise sessions performed on a mechanical brake cycle ergometer at 150% VO2max for 60 seconds. Termination of the supramaximal work bouts were followed by a 20 minutes active recovery period cycling at 30% VO2max and a 20 minutes passive recovery period sitting quietly. Following the recovery modes, isokinetic measures of peak torque, total work output and fatigue were evaluated in the dominant quadricep muscle group. During the control test, exercise performance was limited to that of isokinetic evaluation. The order of the experimental and control tests were randomly assigned. Postexercise blood lactate levels prior to the isokinetic muscle test were 9.2 and 9.1 mM during the active and passive recovery conditions respectively. Blood lactate concentration during the control test was .4 mM prior to the isokinetic muscle test. The rate of blood lactate disappearance was significantly greater during active recovery (3.5 mM) when compared with passive recovery (7.2 mM). Blood lactate concentration during the control test was significantly lower (.4 mM) in comparison to both active and passive lactate concentrations prior to the isokinetic muscle test. Despite significant differences in blood lactate between active and passive recovery conditions, there was no difference in isokinetic measures of maximal strength, work output and muscle fatigue between recovery modes. Further indication that lactate is unrelated to muscle function was the nonsignificant finding in muscle function between the control and experimental conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

[Hemodynamic responses to sublingual nifedipine during exercise and recovery in congestive heart failure].

To elucidate the hemodynamic responses to sublingual nifedipine administration during exercise and recovery in congestive heart failure, 16 patients with dilated cardiomyopathy (DCM) and 11 controls were studied using supine bicycle exercise testing. The cardiac index (CI) was measured at rest, at peak exercise and successively during recovery by the thermodilution method. The heart rate (HR), mean blood pressure (mBP) and mean pulmonary arterial pressure (mPAP) were measured every minute. The same exercise load and hemodynamic measurements were repeated about 30 min after the sublingual administration of 10 mg nifedipine. The recovery slope in each parameter was analyzed using an exponential function (Cp = C1ekt). The regression coefficient in each parameter was defined as a CI slope, an HR slope, an mBP slope and an mPAP slope. Before the administration of nifedipine, CI at peak exercise was lower, mPAP during recovery was persistently higher and the CI slope was more blunt in DCM patients, compared with those of the controls. With the administration of nifedipine, CI and HR increased or tended to increase, mBP decreased throughout the exercise and recovery, and mPAP decreased at rest, at peak exercise and one min after exercise in the controls. In DCM patients, however, the CI increased, mBP and mPAP decreased nearly throughout the exercise and recovery, while HR increased throughout the exercise and recovery, except at peak exercise. The CI, HR and mPAP slopes were blunted in the controls; whereas, each slope showed no change in DCM patients. These results suggest that sublingual nifedipine administration can reduce both the preload and afterload, and increase CI throughout exercise and recovery without significant alteration in the recovery course.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Sublingual↗

Effect of administration of prostaglandin F2 alpha on embryo recovery from the uterus on day 5 after ovulation in mares.

Ten mares were used to investigate the effect of administration of prostaglandin F2 alpha on uterine tubal motility, as reflected by embryo recovery from the uterus 5 days after ovulation (day 0). Mares were assigned to 3 groups: group A, uterine flush for embryo recovery on day 7; group B, uterine flush for embryo recovery on day 5; and group C, uterine flush for embryo recovery on day 5, after treatment with prostaglandin F2 alpha (10 mg, IM) on day 3. Each mare was assigned to each group once. Embryo recovery rates for the 3 groups were: A, 6 of 10; B, 2 of 8; and C, 0 of 10. The embryo recovery rate for group C was significantly lower (P less than 0.01) than that for group A. Embryo recovery rate for group B was not significantly different from group A or group C. Administration of prostaglandin on day 3 did not increase embryo recovery rate from the uterus on day 5. Additionally, the 25% embryo recovery rate (2 of 8) for group B mares suggested an earlier time for entry of the embryo into the uterus than has previously been reported.

Animals↗

Progenitor cell numbers (CFU-GM, CFU-D, and CFU-Mix) and hemopoietic recovery following autologous marrow transplantation.

Forty-one consecutive patients were treated with high-dose chemotherapy with or without total body irradiation followed by autologous marrow transplantation. Four treatment regimens of varying intensity were used. Every patient's harvested marrow was evaluable for nucleated cell and progenitor cell loss during the cell separation and cryopreservation process. Of the 41 patients, 38 were evaluable for peripheral blood count recovery. Multivariate analysis of colony-forming cell assays and recovery of neutrophils and platelets showed a significant association with absolute numbers of post-thaw mixed colony-forming units (CFU-Mix) infused (p less than 0.002). Prefreeze CFU-Mix also correlated with recovery to a lesser degree, as did absolute numbers of nucleated cells. The number of diffusion chamber colony-forming units (CFU-D) prefreeze, but not post-thaw infused into the patient, was associated with recovery of neutrophils (p = 0.0001), but not platelets. When the precursor cell numbers were adjusted for body weight, post-thaw CFU-Mix showed the best correlation with recovery of both platelets and neutrophils. Prefreeze CFU-D per kg was also associated with recovery of neutrophils (p = 0.02). To some extent nucleated cells per kg predicted for recovery with neutrophils and platelets (p less than 0.05). When analyzed according to treatment regimen, cyclophosphamide-BCNU-VP16 (CBV) or cyclophosphamide-total body irradiation (CY/TBI) was associated with prolonged recovery compared to cyclophosphamide-adriamycin-vinblastine (CAV) or etoposide-cyclophosphamide (EC). In this setting only CFU-D number predicted neutrophil recovery (p less than 0.002). We conclude that determination of the number of total nucleated cells, CFU-D, and CFU-Mix, before cryopreservation of the sample is important in predicting hemopoietic reconstitution in autologous bone marrow transplantation.

Antineoplastic Combined Chemotherapy Protocols↗

Cell survival and recovery processes in Chinese hamster AA8 cells and in two radiosensitive clones.

Cell survival and recovery after gamma irradiation were investigated in a Chinese hamster ovary cell line (AA8) and in two radiosensitive clones (EM9 and NM2) derived from it. When analyzed by the multitarget and linear-quadratic equations, the dose-response curves for survival of both EM9 and NM2 cells, compared with AA8 cells, were characterized by a decreased magnitude of the shoulder or single-hit region (as reflected by Dq or alpha, respectively) but no difference in the terminal slope or double-hit region (as reflected by DO or beta, respectively). Recovery from sublethal damage (SLD) and potentially lethal damage (PLD) was measured in the three cell lines to examine the relationship between the shoulder width of the survival curve and the magnitude of cellular recovery. NM2 cells exhibited a reduced shoulder on their survival curve and a reduced capacity for SLD recovery, compared with AA8 cells, after equitoxic doses of radiation. EM9 cells, which also had a reduced shoulder on their survival curve, displayed the same rate and extent of recovery as AA8 cells for both SLD and PLD. PLD recovery, as assayed in fed plateau-phase NM2 cells by delayed plating, occurred with slower initial kinetics but to the same final extent as that in AA8 cells, resulting in modification of both the shoulder and the slope of the survival curve. However, PLD recovery, as assayed in log-phase NM2 cells by postirradiation treatment with hypertonic salt, was normal and affected predominantly the slope of the survival curve. These data demonstrate that although both SLD and PLD recovery play a role in determining cell survival, cell-survival curve parameters may not always be useful in predicting cellular recovery capacity.

Animals↗

Spontaneous recovery of neuromuscular function after atracurium in pediatric patients.

Spontaneous recovery of neuromuscular function after a bolus dose of 0.40 mg/kg atracurium was assessed in 60 newborn to adolescent patients during balanced anesthesia. Each patient was allowed to recover spontaneously until complete recovery of the single twitch (T1) response and the train-of-four ratio measured from the hypothenar muscle evoked compound EMG. The recovery times of T1 from the onset of relaxation to 10% recovery and to 100% recovery were significantly longer in patients under 10 kg of body weight than in the heavier patients (25 and 56 min vs 19 and 45 min, respectively, P less than 0.01). The rate of recovery, calculated as the recovery index (time between 25% recovery and 75% recovery of T1) was significantly longer in patients under 2 months of age than in older infants or children and adolescents. Atracurium remains, nevertheless, a relaxant of intermediate duration of action even in small infants.

Adolescent↗

Effect of leukocyte antibodies and HLA matching on the intravascular recovery, survival, and tissue localization of 111-indium granulocytes.

The effect of leukocyte antibodies detected under different conditions on the fate in vivo of granulocytes was studied using 111-indium-labeled granulocytes. Sera from patients were tested by granulocyte agglutination (GA), granulocytotoxicity (GC), granulocyte immunofluorescence (GIF), lymphocytotoxicity (LC), and antibody-dependent lymphocyte-mediated granulocytotoxicity. Granulocytes from donors to be studied were labeled with 111-indium and injected. Then the intravascular recovery and survival or tissue localization was determined in 93 studies. Antibodies detected by granulocyte agglutination were associated with a significant reduction in recovery (6.7% v 30.8% in controls; P less than .001) and t1/2 (0.3 hours v 5.6 hours in controls; P = .002). When all possible combinations of serum reactivity were considered, reactivity in the GA plus GIF assays had the best correlation with decreased recovery (R2 = .49; P less than .001) and t1/2 (R2 = .73; P less than .001). When the relationship between the strength of antibody reactivity and the recovery and t1/2 were analyzed, the best relationship was between the combination of LC and GIF with recovery (R2 = .62; P = .001). Because of the general availability of the HLA (LC) testing, the role of LC reactivity was investigated in other ways. There was a strong relationship between sera highly reactive by LC and those reactive by GIF. These highly reactive sera were also associated with reduced recovery and t1/2. The influence of specific HLA antigen mismatches was also studied. When donor and recipient were mismatched for the HLA-A2, B8, or BW44 antigens, there was a significant reduction in either recovery, t1/2, or both. Tissue localization was studied by body scans in patients with and without known sites of inflammation. Antibodies detected by a combination of GA and GIF caused abnormal pulmonary sequestration of granulocytes (three cases) and failure of granulocytes to localize at known sites of inflammation (three cases). HLA (LC) antibodies did not alter tissue localization despite the presence of the corresponding HLA antigens on granulocytes. It appears that GA, GIF, or a combination of these tests is the most effective predictor of altered in vivo fate of granulocytes. However, sera highly reactive by LC and GIF probably define a group of highly immunized patients in whom granulocyte recovery and t1/2 are also reduced. Mismatching for certain HLA antigens is also associated with reduced granulocyte recovery and survival. At present, GA, with or without the immunofluorescence assay, is the most effective predictor of altered in vivo granulocyte activity.(ABSTRACT TRUNCATED AT 400 WORDS)

Antibodies↗

[Recovery in aphasia (Part 1)].

In order to elucidate the factors which have an influence on the prognosis of aphasia, a correlation was studied in 76 right-handed aphasic patients between recovery rates and various factors: i.e. aphasia type, age, educational level, time between onset of aphasia and institution of therapy and initial severity. Initial evaluations on Standard Language Test of Aphasia (SLTA) were obtained within 5 months after the cerebrovascular accident and reevaluations were obtained 3 months after the initial evaluation. Recovery rates were determined by comparing scores of these 2 tests in order to coincide with clinical impression. The results obtained were as follows: Aphasia type: The highest recovery rates were seen in conduction aphasics, followed by amnestic, Wernicke, and Broca aphasics. Global aphasics had significantly lower recovery rates. It was suggested that anarthria in Broca's aphasia and jargon in Wernicke's aphasia had a significant ratarding effect on recovery rates. Age: Age and recovery rates showed a significant negative correlation: younger patients recovered better, and this trend was remarkable in Wernicke aphasics but not Broca aphasics. Education: Patients with more education tended to improve more, and this trend was most remarkable in amnestic aphasics. Time between onset of aphasia and institution of therapy: Time elapsed from onset and recovery rates showed a significant negative correlation; recovery rates decreased as the time interval from onset increased. Initial severity: Correlation between the initial severity of aphasia, measured by the initial SLTA scores and recovery rates was very high; severily affected aphasics recovered to a lesser extent than mildly affected ones and this trend was remarkable in Wernicke and Broca aphasics.

Adult↗

Effect of hypertransfusion on bone marrow regeneration in sublethally irradiated mice. II. Enhanced recovery of megakaryocytes and platelets.

Hypertransfusion can enhance myeloid recovery after bone marrow depletion, but its influence on thrombopoietic recovery has not been previously defined. We have studied the pattern of platelet and megakaryocyte recovery in mice hypertransfused after receiving 350 rad whole body irradiation. The platelet counts of the hypertransfused group showing an initial fall due to hemodilution in the expanded blood volume and then fell to a lower nadir than that of the control mice. The rate of platelet recovery was more rapid in the hypertransfused mice. Bone marrow megakaryocyte concentrations in both groups showed a degenerative phase, abortive rise, and regenerative phase. The decrease in megakaryocytes was the same in both groups. The hypertransfused mice showed a greater abortive rise in megakaryocyte concentration preceded by the appearance of a greater number of large megakaryocytes in the bone marrow. However, the most striking effect of hypertransfusion was on megakaryocyte recovery. Although the time of onset of recovery was not different, the rate of recovery was approximately twice as rapid in the hypertransfused group. Administration of daily erythropoietin to hypertransfused mice abolished this more rapid recovery. Thus, the presence of a simultaneous demand for erythroid precursors does affect the rate of megakaryocyte regeneration. Just as the more rapid recovery of granulopoiesis following hypertransfusion may be clinically beneficial, the more rapid reconstitution of thrombopoiesis may also offer clinical advantage in some circcumstances.

Animals↗

Effect of passive and active recovery on the resynthesis of muscle glycogen.

The purpose of this investigation was to determine the effect of passive and active recovery on the resynthesis of muscle glycogen after high-intensity cycle ergometer exercise in untrained subjects. In a cross-over design, six college-aged males performed three, 1-min exercise bouts at approximately 130% VO2max with a 4-min rest period between each work bout. The exercise protocol for each trial was identical, while the recovery following exercise was either active (30 min at 40-50% VO2max, 30-min seated rest) or passive (60-min seated rest). Initial muscle glycogen values averaged 144.2 +/- 3.8 mmol.kg-1 w.w. for the active trial and 158.7 +/- 8.0 mmol.kg-1 w.w. for the passive trial. Corresponding immediate postexercise glycogen contents were 97.7 +/- 5.4 and 106.8 +/- 4.7 mmol.kg-1 w.w., respectively. These differences between treatments were not significant. However, mean muscle glycogen after 60 min of passive recovery increased 15.0 +/- 4.9 mmol.kg-1 w.w., whereas it decreased 6.3 +/- 3.7 mmol.kg-1 w.w. following the 60 min active recovery protocol (P < 0.05). Also, the decrease in blood lactate concentration during active recovery was greater than during passive recovery and significantly different at 10 and 30 min of the recovery period (P < 0.05). These data suggest that the use of passive recovery following intense exercise results in a greater amount of muscle glycogen resynthesis than active recovery over the same duration.

Adult↗

In vitro split-dose recovery of glioblastoma multiforme.

Glioblastoma multiforme is among the most clinically resistant tumors to radiation. This resistance may be due to several different factors, such as a low intrinsic radiation sensitivity, a high recovery capacity, an increased number of clonogens, and a high hypoxic fraction. Previously, we have demonstrated a very wide range of intrinsic radiation sensitivities of cells of glioblastoma multiforme cell lines in vitro after single-dose irradiation. That is, the cells of some glioblastoma multiforme cell lines were quite sensitive, while for others the sensitivity of glioblastoma multiforme was among the lower range of sensitivities reported in the literature. This finding indicates that inherent cellular radiation sensitivity is not the sole determinant of the in vivo response of glioblastoma multiforme tumors. In this report, we evaluate the role of split-dose recovery determined in vitro in relation to the poor clinical outcome of glioblastoma multiforme. Cells of seven early-passage glioblastoma multiforme cell lines and six cell lines derived from tumors of a type frequently treated successfully (two squamous cell carcinomas of head and neck, three breast cancers, and one low-grade astrocytoma cell line) were studied. The in vitro split-dose recovery has been measured using colony formation as an end point. The cells were maintained at 37 degrees C for a period of 6 h between the doses of radiation. Results are presented in terms of a recovery ratio: the ratio of the mean inactivation dose of split-dose radiation to that of single-dose radiation. The data show significantly higher recovery ratios for glioblastoma multiforme than for the other types of histology; however, glioblastoma multiforme showed a wide range of recovery ratios, varying from 1.12 to 2.02. This indicates that cells of some glioblastoma multiforme cell lines exhibit minimal split-dose recovery. No correlation was found between the recovery ratio and the intrinsic radiation sensitivity of the cell lines studied. From these data, we conclude that the recovery capacity may not be the major determinant of the clinical radiation resistance of some glioblastoma multiforme.

Cell Survival↗