The prognosis of a normal stress-only Tc-99m myocardial perfusion imaging study.

BACKGROUND: Stress-only imaging saves time and radiation exposure, but apprehension remains about the reliability, diagnostic, and prognostic accuracy of a normal stress-only study. The objective of this study was to determine the prognosis of stress-only SPECT MPI in routine clinical practice. METHODS: Patients at lower pre-test risk for CAD presenting for a Tc-99m SPECT MPI over a 2-year period underwent a stress-only protocol. If the stress images were normal (attenuation correction was routinely acquired on all patients), rest imaging was not done. Outcomes of the stress-only group were compared to a full rest-stress protocol cohort. Only patients with normal perfusion and left ventricular function, and no known CAD, were included. All-cause mortality was determined using the Social Security Death Index and specific causes of death were determined using the National Death Index. The difference in all-cause and cardiac mortality between groups in the presence of competing risks was assessed using log-normal survival models. RESULTS: Out of 10,609 patients studied during the time period, 1,673 had a normal stress-only study and 3,237 had a normal rest-stress study. At one year, there were 20 total and 3 cardiac deaths (1.2% and 0.2% mortality) in the stress-only group, and 40 total and 4 cardiac deaths (1.2% and 0.1% mortality) in the rest-stress cohort. At the end of follow-up (40 +/- 9 months), there were 46 total and 7 cardiac deaths (2.7% and 0.4% mortality) in the stress-only group, and 119 total and 17 cardiac deaths (3.7% and 0.5% mortality) in the rest-stress cohort. No significant difference between the stress-only and rest-stress cohorts was found after controlling for confounding variables for both all-cause mortality (p = .94) and cardiac mortality (p = .82). CONCLUSIONS: A normal stress-only MPI has an excellent short-term prognosis (both for all-cause and cardiac mortality) comparable to that of a normal rest-stress MPI study.

Complement component C3 allotypes and outcomes in liver transplantation.

The complement system has been implicated in the pathogenesis of liver diseases. Human complement component C3 (C3) exists as 2 allotypes, fast (F) and slow (S). We conducted a study to address the influence of these alleles on ischemia-reperfusion (IR) injury and graft survival in liver transplant recipients. Four hundred thirty patients receiving liver transplants from 2000 to 2004 were included. C3 allotypes of 296 donor-recipient pairs were determined and correlated with clinical outcomes. Four groups were analyzed according to the C3 genotype: C3 SS donor and recipient, C3 FS or C3 FF donor and C3 SS recipient, C3 SS donor and C3 FS or C3 FF recipient, and C3 FS or C3 FF donor and recipient. Baseline characteristics of the 4 groups were similar. The mean follow-up time was 4.3 +/- 2.2 years. The 4 groups had similar rates of IR injury (P = 0.16). The hazard ratios for liver allograft survival in the C3 SS donor and recipient group in comparison with the other 3 groups (C3 FS or C3 FF donor and C3 SS recipient, C3 SS donor and C3 FS or C3 FF recipient, and C3 FS or C3 FF donor and recipient) were not significantly different: 1.13 (P = 0.60), 0.99 (P = 0.97), and 1.02 (P = 0.95), respectively. In conclusion, donor and recipient C3 genotypes are not associated with liver transplantation outcomes.

Human CD34+ cells are capable of generating normal and JAK2V617F positive endothelial like cells in vivo.

Endothelial like cells (ELCs) are thought to originate from either a hierarchy of endothelial progenitor cells (EPC), monocytes or monocyte derived multipotent progenitor cells (MOMCs). In this report, the ability of CD34(+) cells to generate ELC in vivo was examined using an immunodeficient mouse transplant assay system. The Philadelphia chromosome negative (Ph(-)) myeloproliferative neoplasms (MPN) are associated with the acquired mutation, JAK2V617F. In order to further examine the ability of cord blood and JAK2V617F positive MPN CD34(+) cells to generate ELC, CD34(+) cells were transplanted into NOD/SCID mice. Cells within the livers and lungs of recipient mice had phenotypic and molecular properties of human ELC as examined using RT-PCR, flow cytometric analysis and fluorescence microscopy. These cells possessed either human wild type JAK2 or JAK2V617F indicating that they were derived from the transplanted human cells and that a fraction of such cells were involved by the malignant process. Furthermore, human CD144(+) cells isolated from the livers of recipient mice formed clusters in vitro composed of ELC, which contained either wild type JAK2 or JAK2V617F suggesting that these cells are derived from either MOMC or EPC that have an extensive proliferative capacity as well as some degree of self renewal capacity. These studies indicate that adult CD34(+) cells can be affected by JAK2V617F and that they can generate ELC which might play a role in the development of thrombosis in patients with MPN.