John D. Kalbfleisch

More Rapid, Complete, and Stable Coronary Thrombolysis With Bolus Administration of Reteplase Compared With Alteplase Infusion in Acute Myocardial Infarction

BACKGROUND Early restoration and maintenance of normal (TIMI 3) blood flow during acute myocardial infarction is critical for optimal preservation of left ventricular function and survival. Recombinant plasminogen activator (r-PA, reteplase) is a nonglycosylated deletion mutant of wild-type tissue-type plasminogen activator (TPA) that has been shown to achieve more rapid and complete thrombolysis compared with other plasminogen activators in animal models. METHODS AND RESULTS The RAPID Trial was designed to test the hypothesis that bolus administration of one or more dosage regimens of r-PA was superior to standard-dose alteplase (TPA) in achieving infarct-related artery patency 90 minutes after initiation of treatment. Six hundred six patients with acute myocardial infarction were randomized to one of four treatment arms: (1) TPA 100 mg i.v. over 3 hours, (2) r-PA as a 15-MU single bolus, (3) r-PA as a 10-MU bolus followed by 5 MU 30 minutes later, or (4) r-PA as a 10-MU bolus followed by 10 MU 30 minutes later. Coronary arteriography was performed at 30, 60, and 90 minutes after initiation of treatment and at hospital discharge. The 10 + 10-MU r-PA group achieved better 90-minute and 5- to 14-day TIMI 3 flow (63% [CI, 55% to 71%] versus 49% [41% to 57%], P = .019, and 88% [82% to 94%] versus 71% [63% to 79%], P < .001, respectively) than the TPA group. The TIMI 3 flow in the 10 + 10-MU r-PA group at 60 minutes was equivalent to that in the TPA group at 90 minutes (51 versus 49%). Global ejection fraction and regional wall motion in the 10 + 10-MU r-PA group were superior to those of the TPA group at hospital discharge (53 +/- 1.3% versus 49 +/- 1.3%, P = .034; -2.19 +/- 0.12 versus -2.61 +/- 0.13 SD per chord, P = .02, respectively). The 15-MU and 10 + 5-MU r-PA patency and left ventricular function results were similar to those of the TPA and inferior to those of the 10 + 10-MU r-PA group. Bleeding complications were similar between the groups. CONCLUSIONS r-PA given as a double bolus of 10 + 10 MU achieves more rapid, complete, and sustained thrombolysis of the infarct-related artery than standard-dose TPA, without an apparent increased risk of complications. This was associated with improved global and regional left ventricular function at hospital discharge.

The Analysis of Current Status Data on Point Processes

Abstract This article considers the analysis of event count data in which each subject is observed at only one time point and no information is available on subjects between their entry time and observation points. This type of data, often referred to as current status data, arises frequently—for example, in demography, epidemiology, and reliability studies. Statistical methods for the analysis of current status data from point processes are proposed. Specifically, a statistic for testing the equality of the mean functions of point processes is presented and its asymptotic distribution obtained. For illustration, the proposed method is used to analyze multiple tumor data from a tumorgenicity experiment, with focus on the comparison of tumor growth rates in male and female rats. The adequacy of the asymptotic distribution of the test statistic is evaluated in a small simulation study. Power comparisons with the usual parametric model are also obtained. Finally, some possible directions for further research...

Recovery of in vivo cellular immunity after human marrow grafting: influence of time postgrafting and acute graft-versus-host disease

Three hundred thirty-two marrow graft recipients and 241 healthy marrow donors were studied by skin testing with recall and neoantigens. Two hundred thirty patients with leukemia and seventy-eight patients with aplastic anemia received allogeneic HLA-identical sibling marrow. Twenty-four patients with leukemia received syngeneic marrow. The conditioning regimen prior to marrow infusion consisted of 120 mg/kg cyclophosphamide and 9.2–15.75 Gy total-body irradiation (leukemia) or 200 mg/kg cyclophosphamide (aplastic anemia). The patients were skin-tested with the neoantigens dinitrochlorobenzene (DNCB)4, keyhole limpet hemocyanin, and a battery of five recall antigens around 100, 150, 365, 730, 1095, 1460, and 1825 days after grafting. A binary logistic regression analysis was used to investigate the factors thought to influence immunocompetence. At 3 months postgrafting, the proportion of patients positive to DNCB was equal to that of normal marrow donors, but thereafter it was lower until 2 years. The proportion of patients positive to keyhole limpet hemocyanin was lower than normal regardless of the time after grafting. The proportion of patients positive to recall antigens was lower than that of normal marrow donors until 4 years after grafting. Patients with a history of acute graft-versus-host disease had the lowest probability of a positive reaction to recall antigens. None of the other factors was significantly associated with an increased or reduced level of response.

On the use of case series to identify disease risk factors.

Methods to identify disease risk factors from a series of cases are considered. These include methods that compare risk factor levels among diagnostic categories and methods that relate risk factor levels to age at diagnosis, with a single diagnostic category. Statistical aspects considered include modelling assumptions, parameter identifiability, hypothesis-testing efficiency, assumptions concerning unsampled diagnostic categories and requirements for risk factor data and confounding factor data. It is argued that methods to identify risk factors using data on a single diagnostic category involve such strong assumptions that they have limited usefulness. Analyses that compare risk factor levels among diagnostic categories, on the other hand, should continue to play an important role in epidemiologic research, though there are important limitations in relation to analyses involving disease-free controls.

The Toll-like receptor 9 ligand, CpG oligodeoxynucleotide, attenuates cardiac dysfunction in polymicrobial sepsis, involving activation of both phosphoinositide 3 kinase/Akt and extracellular-signal-related kinase signaling.

BACKGROUND Toll-like receptors (TLRs) play a role in the pathophysiology of sepsis and multiple organ failure. This study examined the effect of CpG oligodeoxynucleotide (CpG-ODN), the TLR9 ligand, on polymicrobial sepsis-induced cardiac dysfunction. METHODS Male C57BL/6 mice were treated with CpG-ODN, control CpG-ODN (control-ODN), or inhibitory CpG-ODN (iCpG-ODN) 1 hour prior to cecal ligation and puncture (CLP)-induced sepsis. Mice that underwent sham surgery served as sham controls. Cardiac function was examined by echocardiography before and 6 hours after CLP. RESULTS Cardiac function was significantly decreased 6 hours after CLP. CpG-ODN prevented CLP-induced cardiac dysfunction, as evidenced by maintenance of the ejection fraction and fractional shortening. Control-ODN or iCpG-ODN did not alter CLP-induced cardiac dysfunction. CpG-ODN significantly attenuated CLP-induced myocardial apoptosis and increased myocardial Akt and extracellular-signal-related kinase (ERK) phosphorylation levels following CLP. In vitro experiments demonstrated that CpG-ODN promotes an association between TLR9 and Ras, resulting in Akt and ERK phosphorylation. Inhibition of phosphoinositide 3-kinase (PI3K) by Ly294002 or inhibition of ERK by U0126 in vivo abolished CpG-ODN attenuation of CLP-induced cardiac dysfunction. CONCLUSIONS CpG-ODN prevents CLP-induced cardiac dysfunction, in part through activation of PI3K/Akt and ERK signaling. Modulation of TLR9 could be an effective approach for treatment of cardiovascular dysfunction in patients with sepsis or septic shock.

MicroRNA-214 protects against hypoxia/reoxygenation induced cell damage and myocardial ischemia/reperfusion injury via suppression of PTEN and Bim1 expression

Background Myocardial apoptosis plays an important role in myocardial ischemia/reperfusion (I/R) injury. Activation of PI3K/Akt signaling protects the myocardium from I/R injury. This study investigated the role of miR-214 in hypoxia/reoxygenation (H/R)-induced cell damage in vitro and myocardial I/R injury in vivo. Methods and Results H9C2 cardiomyoblasts were transfected with lentivirus expressing miR-214 (LmiR-214) or lentivirus expressing scrambled miR-control (LmiR-control) respectively, to establish cell lines of LmiR-214 and LmiR-control. The cells were subjected to hypoxia for 4 h followed by reoxygenation for 24 h. Transfection of LmiR-214 suppresses PTEN expression, significantly increases the levels of Akt phosphorylation, markedly attenuates LDH release, and enhances the viability of the cells subjected to H/R. In vivo transfection of mouse hearts with LmiR-214 significantly attenuates I/R induced cardiac dysfunction and reduces I/R-induced myocardial infarct size. LmiR-214 transfection significantly attenuates I/R-induced myocardial apoptosis and caspase-3/7 and caspase-8 activity. Increased expression of miR-214 by transfection of LmiR-214 suppresses PTEN expression, increases the levels of phosphorylated Akt, represses Bim1 expression and induces Bad phosphorylation in the myocardium. In addition, in vitro data shows transfection of miR-214 mimics to H9C2 cells suppresses the expression and translocation of Bim1 from cytosol to mitochondria and induces Bad phosphorylation. Conclusions Our in vitro and in vivo data suggests that miR-214 protects cells from H/R induced damage and attenuates I/R induced myocardial injury. The mechanisms involve activation of PI3K/Akt signaling by targeting PTEN expression, induction of Bad phosphorylation, and suppression of Bim1 expression, resulting in decreases in I/R-induced myocardial apoptosis.