MPI Groups Research Articles

SLAP Trial: Shock Wave Lithotripsy and Mechanical Percussion Therapy Post ESWL for Renal Calculi.

We conducted a prospective randomised control trial. Included patients were males and females greater than 18 years of age with single or multiple ipsilateral renal calculi of total ≤10 mm on plain X-ray and noncontrast CT KUB. ESWL was performed at a single centre, at supine position under general anaesthesia with maximum 3000 shocks at a rate of 100 shocks per minute. Patients were discharged and randomised to either the control arm or MPI therapy. MPI therapy was self-directed in a home setting for 10 minutes a day, three times per week. Both arms had standard follow-up at 12 weeks with a plain X-ray KUB. Patients in the control group were offered cross over to the MPI arm after 12 weeks if residual stone fragments were detected. Statistical analysis was performed using SPSS software via Chi squared and Fisher's exact tests. Ethical approval was obtained via the Prince Charles Hospital HREC Committee, HREC/2022/QPCH/84961. 70 patients met inclusion criteria and underwent ESWL, and 5 were withdrawn. 33 patients were randomised to the MPI group and 32 to the control group. MPI significantly increased the stone clearance rate anywhere in the kidney (87.9% in the MPI group versus 59.4% in the control group, p=0.089), as well as the clearance rate in the lower pole (91.7% in the MPI group versus 63.2% in the control group, p=0.022). Delayed percussion did not improve the clearance rate over primary percussion (p=0.835). This study has shown that MPI can be effectively performed in a home setting without the need for medical supervision and results in improved stone clearance rates post ESWL. The main limitations to the study were the use of X-ray over CT during the follow-up and variability in MPI compliance and administration. Further research is warranted into standardising home MPI protocols. This trial is registered with ANZCTR387061.

Definitions of recovery and reintegration across the first year: A qualitative study of perspectives of persons with spinal cord injury and caregivers.

Longitudinal, qualitative cohort study. To understand how people with newly acquired spinal cord injury (PWS) and their support person (SP) define recovery and successful community reintegration (CR) across the first 12 months post-injury (mpi) and their satisfaction with the rate of recovery and reintegration experienced. Academic and Veterans hospitals in Midwest USA. In-depth, semi-structured interviews were conducted in two cohorts of PWS and SP during the initial inpatient rehabilitation stay, at 6 mpi, and at 12 mpi. Recordings were transcribed; four authors independently undertook line-by-line coding. The team discussed codes to reach consensus and synthesize into broader themes within the International Classification of Function, Disability, and Health and Transformative frameworks. Data are reported on 23 PWS and 21 SP. PWS and SP are similar in defining recovery as gaining motor function and achieving independence. However, SP more frequently define recovery in terms of maintaining positivity and emotional recovery. At 12 mpi both groups shift to define recovery according to progress. Social roles, being active, and employment are persistent themes of how PWS and SP define successful CR. However, SP also frequently define successful CR as reestablishing identity and emotional adjustment. Veterans with SCI less frequently defined successful CR as employment. This study is the first to reveal how PWS and SP define recovery and reintegration during the first 12 mpi. Given decreasing lengths of stay, this information can be used to tailor rehabilitation strategies during the critical first year of injury to optimize recovery.

Incremental value of epicardial fat volume to coronary artery calcium score and traditional risk factors for predicting myocardial ischemia in patients with suspected coronary artery disease

BackgroundEpicardial fat volume (EFV) has been reported to be associated with coronary artery disease (CAD). CAD is the leading cause of myocardial ischemia and myocardial ischemia is closely related to major adverse cardiovascular events. We hypothesized that EFV could provide incremental value to traditional risk factors and coronary artery calcium score (CACS) in predicting myocardial ischemia in Chinese patients with suspected CAD. MethodsWe retrospectively studied 204 Chinese patients with suspected CAD who underwent single-photon emission computerized tomography-myocardial perfusion imaging (SPECT-MPI) combined with computed tomography (CT). Pericardial contours were manually defined, and EFV was automatically calculated. A reversible perfusion defect with summed difference score (SDS) ≥ 2 was defined as myocardial ischemia. ResultsThe myocardial ischemia group had higher EFV than normal MPI group (137.80 ± 34.95cm3 vs. 106.63 ± 29.10 cm3, P < .001). In multivariable logistic regression analysis, high EFV was significantly associated with myocardial ischemia [odds ratio (OR): 8.30, 95% CI: 3.72-18.49, P < .001]. Addition of EFV to CACS and traditional risk factors could predict myocardial ischemia more effectively, with larger AUC .82 (P < .001), positive net reclassification index .14 (P = .04) and integrated discrimination improvement .14 (P < .001). The bootstrap resampling method (times = 500) was used to internally validation and calculate the 95% confidence interval (CI) of the AUC (95% CI .75-.87). The calibration curve for the probability of myocardial ischemia demonstrated good agreement between prediction and observation. ConclusionsIn Chinese patients with suspected CAD, EFV was significantly associated with myocardial ischemia, and improved prediction of myocardial ischemia above traditional risk factors and CACS.

Profiles of Teacher Professional Identity Among Student Teachers and Its Association With Mental Health.

In recent years, studies exploring the link between teacher professional identity and mental health are increasing. However, such research using latent profile analysis is still scarce. The aim of this study was to examine the heterogeneity of a sample of 923 student teachers' professional identity and its association with mental health (i.e., psychological wellbeing and anxiety). By using latent profile analysis, four different profiles were identified: (1) low professional identity (LPI, 5.1%), (2) moderate professional identity (MPI, 42.7%), (3) high occupational values (HOV, 12%), and (4) high professional identity (HPI, 40.2%). The results demonstrated that psychological wellbeing and anxiety were significantly different across the four profiles. In addition, the anxiety of HOV group was not significantly with LPI and MPI groups. This study indicated that student teachers in different groups may have different mental health status.

Metformin Attenuates Ischemia-Reperfusion Injury in a Rat Lung Transplantation Model

<h3>Purpose</h3> Ischemia-reperfusion injury (IRI), an inevitable acute lung injury during lung transplantation (LTx), contributes to the development of severe complications and limits the success of LTx. Metformin exerts beneficial actions to alleviate acute lung injury induced by a diversity of factors. However, the effect of metformin on IRI has not yet been elucidated in LTx. In this study, we conducted an animal experiment to investigate the effects of metformin on IRI and explore the possible therapeutic mechanism. <h3>Methods</h3> LTx was performed on five groups of rats: sham operation (SM), ischemia-reperfusion (IR), metformin-IR (MI), metformin-anisomycin (MAPK activator)-IR (MAI), metformin-phorbol 12-myristate 13-acetate (PMA, NETosis activator)-IR (MPI). In MI, MAI, and MPI groups, metformin (400 mg/kg) was administered by gavage 72h, 48h, 24h, and 30min before cold ischemia. Anisomycin (15 mg/kg) and PMA (3 ug/kg) were intraperitoneally injected 30min before cold ischemia in MAI and MPI groups, respectively. Each group (n = 5) received a cold ischemic time of 1.5h followed by LTx except the SM group (n = 5). After reperfusion for two hours, recipient rats were sacrificed for further examination of arterial blood gas analysis, histopathology examination, and lung wet-to-dry weight (W/D) ratio. <h3>Results</h3> Compared to the IR group, the MI group showed significantly better PaO₂/FiO₂ ratio and SaO₂, lower W/D ratio, perivascular cuff area/vessel area (P/V) ratio, lung injury score, and red blood cell (RBC) infiltration (all <i>P</i> < 0.05). After the administration of MAPK signaling pathway and NETosis activators, significant deterioration was found in the MAI group with higher lung injury score, RBC infiltration, and W/D ratio (all <i>P</i> < 0.05) and the MPI group with lower SaO₂ and higher lung injury score and P/V ratio (all <i>P</i> < 0.05) (Figure 1). <h3>Conclusion</h3> Metformin attenuates IRI and may be attributed to inhibition of MAPK signaling pathway and NETosis in rat LTx.

Mortality in Stable Coronary Disease in Patients With Intermediate- or High-Risk Myocardial Perfusion Imaging

The management of patients with stable coronary disease and intermediate- or high-risk features on single photon emission computed tomography myocardial perfusion imaging (SPECT MPI) continues to be controversial as to whether they should be treated with an initial invasive strategy (catheterization and revascularization when feasible) or medical therapy alone to improve mortality. We performed a retrospective observational study of 1,946 patients with intermediate- or high-risk SPECT MPI scans performed over a 6-year period (from 2014 to 2019). Each patient was followed from the time of SPECT MPI to 16 months after the last patient was enrolled. The primary end point was all-cause mortality and the secondary end point cardiovascular mortality. Of the eligible 1,697 patients, 1,144 had an intermediate-risk scan, 553 a high-risk scan, 915 had medical therapy alone, and 782 went on an initial invasive strategy. All patients were divided into the following three groups: combined SPECT MPI (both intermediate- and high-risk), high-risk SPECT MPI, and intermediate-risk SPECT MPI groups. After propensity score matching, there was a statistically significant difference in cardiovascular death (5.9% vs 2.7%; p=0.038) in the medical therapy cohort compared with initial invasive cohort in the combined SPECT MPI group, but no difference in all-cause death (15.7% vs 13%; p=0.318). On subgroup analysis, in intermediate-risk SPECT MPI group, there was no significant difference in either all-cause death (13.8 vs 11.7%; p=0.583) or cardiac death (5.4% vs 2.5%; p=0.16) in conservative cohort compared with invasive strategy cohort. In high-risk SPECT MPI group, conservative therapy cohort had higher cardiac death (11.7% vs 2.5%; p=0.002) compared with initial invasive strategy cohort, but there was no significant difference in all-cause death (24.5% vs 15.3%; p=0.052). In conclusion, this study supports that patients with intermediate- or high-risk SPECT MPI scans when considered together or only with high-risk features, derive a cardiovascular mortality benefit with an initial invasive strategy. Patients who had undergone intermediate-risk SPECT MPI had similar outcomes with either medical therapy alone or initial invasive evaluation.

Incremental prognostic value of SPECT CT based visual calcium score burden for outcomes prediction

Abstract Funding Acknowledgements Type of funding sources: Other. Main funding source(s): Astellas Pharma US Background Coronary calcium is an important non-perfusion finding on SPECT CT attenuation correction (AC) and has been shown to help decrease equivocal interpretation and identifying atherosclerosis despite normal perfusion. Although correlations with measured calcium score have been good, an easy visual calcium score (VCS) for CT AC calcium and its prognostic value has not been well established. Purpose We aimed to evaluate the role of VCS calculated from low-dose CT for AC in predicting outcomes stratified by SPECT (normal versus abnormal). Methods A retrospective data review of patients who underwent cardiac SPECT CT at our center from January 2009 -August 2012 with a mean follow up of 4.5 years. Baseline characteristics and outcomes were collected. VCS scoring was established as follows and was completed on all scans by three senior cardiology fellows. When not congruent, consensus with third reader was established. Presence of visual calcium in any of the following arteries was recorded as a score of 1 with VCS range 0-6: left main, left anterior descending, left circumflex, right coronary, ascending aorta, and descending thoracic aorta. Subjects were divided into 3 groups based on the VCS of &amp;lt;2, 2-4, and &amp;gt;4. Normal versus abnormal SPECT was defined as summed stress score/summed difference score of &amp;lt;4/&amp;lt;2 and &amp;gt; =4/&amp;gt; =2 respectively. Major adverse cardiac events (MACE) defined as presence of heart failure, myocardial infarction, and/or cardiac death. Results 538 consecutive patients with SPECT CT were evaluated. Mean age was 63.3 years with 54% females. There were 463 (86%) normal SPECT and 75 (14%) abnormal SPECT. Using VCS, there was a statistically significant increase in the percentage of MACE over the period of follow-up with step wise increase in VCS severity in normal SPECT group (p-value = 0.001), although not significant in the abnormal MPI group (Figure 1). There was a higher mortality with increasing VCS in both normal and abnormal SPECT (p= &amp;lt;0.001 and p = 0.014 respectively). Using a multivariate logistic regression model in patients with normal SPECT, there were higher odds of death (OR 1.26) with every 1 point of VCS increase controlling for age, sex, baseline heart rate, history of dialysis, diabetes and stroke (95% confidence interval 1.09, 1.45; p-value = 0.002). Conclusion This study highlights the importance of factoring CT AC calcium in risk assessment of SPECT. CT AC calcium represents an easily available and important adjunctive risk marker during SPECT interpretation. A simple VCS as derived in this study can help with the additive risk stratification in both normal and abnormal SPECT and is of an incremental prognostic value for MACE. Clinicians interpreting SPECT should include coronary calcification on AC CT routinely in reports to help management and prognostication decisions. Our study shows that VCS can be a simple easily adopted tool for consistent reporting.

Association Between the Multidimensional Prognostic Index and Mortality During 15 Years of Follow-up in the InCHIANTI Study.

Multidimensional Prognostic Index (MPI) is recognized as a prognostic tool in hospitalized patients, but data on the value of MPI in community-dwelling older persons are limited. Using data from a representative cohort of community-dwelling persons, we tested the hypothesis that MPI explains mortality during 15 years of follow-up. A standardized comprehensive geriatric assessment was used to calculate the MPI and to categorize participants in low-, moderate-, and high-risk classes. The results were reported as hazard ratios (HRs) and the accuracy was evaluated with the area under the curve (AUC), with 95% confidence intervals (CIs) and the C-index. We also reported the median survival time by standard age groups. All 1453 participants (mean age 68.9 years, women = 55.8%) enrolled in the InCHIANTI study at baseline were included. Compared to low-risk group, participants in moderate (HR = 2.10; 95% CI: 1.73-2.55) and high-risk MPI group (HR = 4.94; 95% CI: 3.91-6.24) had significantly higher mortality risk. The C-index of the model containing age, sex, and MPI was 82.1, indicating a very good accuracy of this model in explaining mortality. Additionally, the time-dependent AUC indicated that the accuracy of the model incorporating MPI to age and sex was excellent (>85.0) during the whole follow-up period. Compared to participants in the low-risk MPI group across different age groups, those in moderate- and high-risk groups survived 2.9-7.0 years less and 4.3-8.9 years less, respectively. In community-dwelling individuals, higher MPI values are associated with higher risk of all-cause mortality with a dose-response effect.

AstroABC : An Approximate Bayesian Computation Sequential Monte Carlo sampler for cosmological parameter estimation

Given the complexity of modern cosmological parameter inference where we are faced with non-Gaussian data and noise, correlated systematics and multi-probe correlated data sets, the Approximate Bayesian Computation (ABC) method is a promising alternative to traditional Markov Chain Monte Carlo approaches in the case where the Likelihood is intractable or unknown. The ABC method is called "Likelihood free" as it avoids explicit evaluation of the Likelihood by using a forward model simulation of the data which can include systematics. We introduce astroABC, an open source ABC Sequential Monte Carlo (SMC) sampler for parameter estimation. A key challenge in astrophysics is the efficient use of large multi-probe datasets to constrain high dimensional, possibly correlated parameter spaces. With this in mind astroABC allows for massive parallelization using MPI, a framework that handles spawning of jobs across multiple nodes. A key new feature of astroABC is the ability to create MPI groups with different communicators, one for the sampler and several others for the forward model simulation, which speeds up sampling time considerably. For smaller jobs the Python multiprocessing option is also available. Other key features include: a Sequential Monte Carlo sampler, a method for iteratively adapting tolerance levels, local covariance estimate using scikit-learn's KDTree, modules for specifying optimal covariance matrix for a component-wise or multivariate normal perturbation kernel, output and restart files are backed up every iteration, user defined metric and simulation methods, a module for specifying heterogeneous parameter priors including non-standard prior PDFs, a module for specifying a constant, linear, log or exponential tolerance level, well-documented examples and sample scripts. This code is hosted online at https://github.com/EliseJ/astroABC

Usefulness for Predicting Cardiac Events After Orthotopic Liver Transplantation of Myocardial Perfusion Imaging and Dobutamine Stress Echocardiography Preoperatively

Patients undergoing orthotopic liver transplantation have high rates of cardiac morbidity and mortality. Although guidelines recommend noninvasive stress testing as part of the preoperative evaluation, little data have evaluated clinical outcomes following orthotopic liver transplantation. A retrospective study at 2 high-volume liver transplantation centers was performed. All patients undergoing noninvasive stress testing (myocardial perfusion imaging [MPI] or dobutamine stress echocardiography [DSE]) over a 5-year period were included. Descriptive analyses, including clinical outcomes and perioperative and postoperative ischemic events, were performed. Comparisons were made between subsets of patients within each stress modality based on abnormal versus normal results. A total of 506 patients were included, of which 343 underwent DSE and 163 MPI. Few patients had abnormal results, with 19 (5.5%) in the DSE group and 13 (8%) in the MPI group. Perioperative and postoperative cardiac complications were low (n= 20, 5.8% and n= 3, 0.9% in DSE group and n= 15, 9.2% and n= 3, 1.8% in MPI group). Comparisons between abnormal versus normal findings showed a trend toward periprocedural cardiac complications in the abnormal DSE group (n= 3, 15.8% vs n= 17, 5.25%; p= 0.09) with no difference in 6-month postprocedural complications (n= 0 vs n= 3, 0.9%; p= 1.0). In the MPI group, a trend toward periprocedural ischemic complications (n= 3, 23.1% vs n= 12, 8%; p= 0.1) was noted with no difference in 6-month postprocedural complications (n= 0 vs n= 3, 2%; p= 1.0). In conclusion, our study found a significantly lower than reported cardiac event rate. In addition, it demonstrated that ischemic cardiac events are uncommon in patients with normal stress testing.

Descriptive Analysis of Patients Undergoing Conventional Non-invasive Stress Testing as Part of the Pre-orthotopic Liver Transplant Evaluation

Introduction: Patients undergoing orthotopic liver transplantation (OLT) have high rates of cardiac morbidity and mortality. Although guidelines recommend non-invasive stress testing as part of the preoperative evaluation, little data has evaluated clinical outcomes following OLT. Methods: A retrospective study at two high volume liver transplantation centers was performed. All patients undergoing non-invasive stress testing (myocardial perfusion imaging [MPI] or dobutamine stress echocardiography [DSE]) over a 5-year period were included. Descriptive analyses, including clinical outcomes and peri- and post- operative ischemic events, were performed. Comparisons were made between subsets of patients within each stress modality based on abnormal versus normal results. Results: A total of 506 patients were included, of which 343 underwent DSE and 163 MPI. Few patients had abnormal results, with 19 (5.5%) in the DSE group and 13 (8%) in the MPI. Peri- and post-operative cardiac complications were low (n=20, 5.8% and n=3, 0.9% in DSE group and n=15, 9.2% and n=3, 1.8% in MPI group). Comparisons between abnormal versus normal findings showed a trend toward periprocedural cardiac complications in the abnormal DSE group (n=3, 15.8% versus n=17, 5.25%; p=0.09) with no difference in 6-month post-procedural complications (n=0 versus n=3, 0.9%; p=1.0). In the MPI group, no difference in peri-procedural ischemic complications (n=3, 23.1% versus n=12, 8%; p=0.1) or 6-month post-procedural complications (n=0 versus n=3, 2%; p=1.0) was noted. Conclusion: Our study found a significantly lower than reported cardiac event rate. Additionally, it demonstrated that ischemic cardiac events are uncommon in patients with normal non-invasive stress testing.

In situ and in-transit analysis of cosmological simulations.

Modern cosmological simulations have reached the trillion-element scale, rendering data storage and subsequent analysis formidable tasks. To address this circumstance, we present a new MPI-parallel approach for analysis of simulation data while the simulation runs, as an alternative to the traditional workflow consisting of periodically saving large data sets to disk for subsequent ‘offline’ analysis. We demonstrate this approach in the compressible gasdynamics/N-body code Nyx, a hybrid mbox{MPI}+mbox{OpenMP} code based on the BoxLib framework, used for large-scale cosmological simulations. We have enabled on-the-fly workflows in two different ways: one is a straightforward approach consisting of all MPI processes periodically halting the main simulation and analyzing each component of data that they own (‘in situ’). The other consists of partitioning processes into disjoint MPI groups, with one performing the simulation and periodically sending data to the other ‘sidecar’ group, which post-processes it while the simulation continues (‘in-transit’). The two groups execute their tasks asynchronously, stopping only to synchronize when a new set of simulation data needs to be analyzed. For both the in situ and in-transit approaches, we experiment with two different analysis suites with distinct performance behavior: one which finds dark matter halos in the simulation using merge trees to calculate the mass contained within iso-density contours, and another which calculates probability distribution functions and power spectra of various fields in the simulation. Both are common analysis tasks for cosmology, and both result in summary statistics significantly smaller than the original data set. We study the behavior of each type of analysis in each workflow in order to determine the optimal configuration for the different data analysis algorithms.

Comparison of contrast flow and clinical effectiveness between a modified paramedian interlaminar approach and transforaminal approach in cervical epidural steroid injection

The different methods of cervical epidural injection include the median or paramedian interlaminar (PI) approach and the transforaminal (TF) approach. We hypothesized that the modified PI (mPI) approach could deliver drugs suitably and safely into the anterior epidural space compared with the TF approach. A total of 62 patients were randomized into either the mPI group (n=31) or the TF group (n=31). Contrast to the anterior epidural space (primary outcome, grade 1-3), vascular uptake and discomfort were assessed. Furthermore, pain intensity in the arm and neck [numeric rating scale (NRS)] and the degree of symptoms (5-point Likert scale) before the procedure and 2 weeks, 1 and 3 months following the procedure were compared between two groups. Effectiveness (a secondary outcome) was defined as a ≥50% reduction on the NRS for arm and neck pain and a result of 3 or 4 on the Likert scale at 3 months following the procedure. Contrast to the anterior epidural space in the mPI group was significantly greater than that in the TF group (P=0.036). Vascular uptake and discomfort in the mPI group were significantly lower than those in the TF group (P<0.001, respectively). Of the patients in whom the procedure was effective, 24 (77.4%) were from the mPI group and 20 (64.5%) were from the TF group (P=0.263). This result suggests that the mPI approach allows for suitable and safe delivery of drugs into the anterior epidural space. Institutional Review Board of Seoul National University Bundang Hospital (B-1206/159-004) and Clinical Research Information Service (KCT0000626).

Abstract 1775: Prognostic Value of Exercise and Dobutamine Positron Emission Tomography

Introduction Positron emission tomography (PET) is commonly performed using vasodilator stress, but exercise and dobutamine stress is available to patients with contraindications to vasodilators. Vasodilator PET appears to have prognostic value, however the prognostic value of PET using stressors which induce myocardial ischemia have not been well evaluated. Hypothesis To evaluate the prognostic value of myocardial demand ischemia induced by treadmill exercise and dobutamine PET. Methods 124 patients (mean age = 61.29 ± 10.73 years; 87 men) had treadmill exercise or dobutamine Rb-82 or N-13 ammonia PET. Images were assessed qualitatively using a 17-segment model and a semi-quantitative visual score (five-point scale) to calculate the summed stress score (SSS). Images were categorized as normal (SSS&lt;4), abnormal (SSS ≥ 4) or inconclusive (SSS&lt; 4 and suboptimal treadmill exercise or dobutamine stress). Follow-up was performed to ascertain outcomes (cardiac death, nonfatal MI and/or late revascularization. Results Of the 124 patients, 46 (37.1%) had a normal PET, 15 (12.1%) had an inconclusive study, and 63 (50.1%) had an abnormal PET (mean follow up 2.8 ± 1.4 years). There were no deaths or non-fatal MI but 1 late revascularization (annual event rate = 1.7%) in the group with a normal PET. Abnormal PET MPI group had 15 cardiac events (1 cardiac death, 4 nonfatal MI, and 10 late revascularization) with an annual event rate of 13.0% (p = 0.002). Conclusions Though small, this study suggests that myocardial PET perfusion defects resulting from demand ischemia induced by treadmill exercise and dobutamine stress may have prognostic value.

The effect of matrix metalloproteinase-9 in granulocyte colony stimulation factor-induced stem cell mobilization

To investigate the effects of matrix metalloproteinase-9 (MMP-9) on granulocyte colony stimulation factor (G-CSF)-induced hematopoietic stem/progenitor cell (HSPC) mobilization in healthy donors of hematopoietic stem cells. Peripheral blood (PB) samples and bone marrow (BM) blood samples were collected from 12 healthy donors of hematopoietic stem cell before and 5 days after G-CSF-induced mobilization. CD34(+) cells were isolated and purified. ELISA was used to detect the protein expression of MMP-9 in the peripheral blood and BM blood of the healthy donors. The protein expression of MMP-9 in the BM blood was detected by ELISA and immunohistochemistry, and the stromal cell-derived factor-1 (SDF-1) level in the BM blood was detected by ELISA. The mRNA expression of MMP-9 in the BM blood samples was detected by RT-PCR. HT1080 cells rich in MMP-9 were cultured. CD34(+) cells were co-cultured with the supernatant of HT1080 cell culture fluid. CD34(+) cells cultured in Iscove's modified Dulbecco's medium were used as control group. Fluorescence-activated cell sorter was used to detect the CXCR4 expression on the surface of the CD34(+) cells. In the transwell experiment CD34(+) cells were divided into 4 groups: control group, o-phenanthroline (MMP-9 chemical inhibitor, MPI) group, HT1080 sup group, and HT1080 + MPI group to be co-cultured with buffer, o-phenanthroline, supernatant of culture fluid of HT1080 cells, or supernatant of culture fluid of HT1080 cells Flow cytometry was used to calculate the cell migration capacity. The MMP-9 level of BM and PB of the healthy donors 5 days after G-CSF mobilization were 278 ng/ml +/- 34 ng/ml and 392 ng/ml +/- 284 ng/ml respectively, both significantly higher than those before G-CSF mobilization (42 ng/ml +/- 17 ng/ml and 27 ng/ml +/- 12 ng/ml respectively (P < 0.01 and P < 0.05). Western blotting showed that the SDF-1 level in the supernatant 5 days after G-CSF mobilization was 5.9 ng/ml +/- 1.0 ng/ml, significantly lower than that before G-CSF mobilization (7.2 ng/ml +/- 0.7 ng/ml, P < 0.05). The CXCR4 levels of the CD34(+) cell from both PB and BM blood were up-regulated after co-culture with the supernatant of HT1080 cells (both P < 0.05). The migration capacity of CD34(+) cells cultured in the supernatant of HT1080 cells was increased significantly (P < 0.05), however, this effect could be inhibited by MIP (P < 0.05). The PB WBC numbers of the G-CSF group and G-CSF + MPI group were 14.9 x 10(6)/L +/- 4.3 x 10(6)/L and 12.3 x 10(6)/L +/- 1.2 x 10(6)/L respectively, the PB WBC numbers of the G-CSF + MPI group was significantly lower than that of the G-CSF group (P < 0.05), however, significantly higher than that of the negative control group (6.8 x 10(6)/L +/- 2.5 x 10(6)/L, P < 0.05). The CFU of the G-CSF group was (84 +/- 10) U/2 x 10(5) MNC, significantly higher than that of the G-CSF + MPI group, (69 +/- 3) U/2 x 10(5) MNC (P < 0.05). The BM MNC number of the G-CSF group was 12.7 x 10(6)/L +/- 0.7 x 10(6)/L, not significantly different from that of the G-CSF + MPI groups (13.1 x 10(6)/L +/- 1.3 x 10(6)/L; P > 0.05). MMP-9 probably facilitates HSPC mobilization by degrading SDF-1, up-regulating CXCR4 expression on the CD34(+) cells, and increasing the migration ability of CD34(+) cells.