Enhancers of Polycomb EPC1 and EPC2 sustain the oncogenic potential of MLL leukemia stem cells.

Through a targeted knockdown (KD) screen of chromatin regulatory genes, we identified the EP400 complex components EPC1 and EPC2 as critical oncogenic cofactors in acute myeloid leukemia (AML). EPC1 and EPC2 were required for the clonogenic potential of human AML cells of multiple molecular subtypes. Focusing on MLL-mutated AML as an exemplar, Epc1 or Epc2 KD-induced apoptosis of murine MLL-AF9 AML cells and abolished leukemia stem cell potential. By contrast, normal hematopoietic stem and progenitor cells (HSPC) were spared. Similar selectivity was observed for human primary AML cells versus normal CD34(+) HSPC. In keeping with these distinct functional consequences, Epc1 or Epc2 KD-induced divergent transcriptional consequences in murine MLL-AF9 granulocyte-macrophage progenitor-like (GMP) cells versus normal GMP, with a signature of increased MYC activity in leukemic but not normal cells. This was caused by accumulation of MYC protein and was also observed following KD of other EP400 complex genes. Pharmacological inhibition of MYC:MAX dimerization, or concomitant MYC KD, reduced apoptosis following EPC1 KD, linking the accumulation of MYC to cell death. Therefore, EPC1 and EPC2 are components of a complex that directly or indirectly serves to prevent MYC accumulation and AML cell apoptosis, thus sustaining oncogenic potential.

TTC5 is required to prevent apoptosis of acute myeloid leukemia stem cells.

Using a screening strategy, we identified the tetratricopeptide repeat (TPR) motif protein, Tetratricopeptide repeat domain 5 (TTC5, also known as stress responsive activator of p300 or Strap) as required for the survival of human acute myeloid leukemia (AML) cells. TTC5 is a stress-inducible transcription cofactor known to interact directly with the histone acetyltransferase EP300 to augment the TP53 response. Knockdown (KD) of TTC5 induced apoptosis of both murine and human AML cells, with concomitant loss of clonogenic and leukemia-initiating potential; KD of EP300 elicited a similar phenotype. Consistent with the physical interaction of TTC5 and EP300, the onset of apoptosis following KD of either gene was preceded by reduced expression of BCL2 and increased expression of pro-apoptotic genes. Forced expression of BCL2 blocked apoptosis and partially rescued the clonogenic potential of AML cells following TTC5 KD. KD of both genes also led to the accumulation of MYC, an acetylation target of EP300, and the form of MYC that accumulated exhibited relative hypoacetylation at K148 and K157, residues targeted by EP300. In view of the ability of excess cellular MYC to sensitize cells to apoptosis, our data suggest a model whereby TTC5 and EP300 cooperate to prevent excessive accumulation of MYC in AML cells and their sensitization to cell death. They further reveal a hitherto unappreciated role for TTC5 in leukemic hematopoiesis.

DNA damage-induced cell-cycle arrest of hematopoietic cells is overridden by activation of the PI-3 kinase/Akt signaling pathway.

Exposure of hematopoietic cells to DNA-damaging agents induces cell-cycle arrest at G1 and G2/M checkpoints. Previously, it was shown that DNA damage-induced growth arrest of hematopoietic cells can be overridden by treatment with cytokine growth factors, such as erythropoietin (EPO) or interleukin-3 (IL-3). Here, the cytokine-activated signaling pathways required to override G1 and G2/M checkpoints induced by gamma-irradiation (gamma-IR) are characterized. Using factor-dependent myeloid cells stably expressing EPO receptor (EPO-R) mutants, it is shown that removal of a minimal domain required for PI-3K signaling abrogated the ability of EPO to override gamma-IR-induced cell-cycle arrest. Similarly, the ability of cytokines to override gamma-IR-induced arrest was abolished by an inhibitor of PI-3K (LY294002) or by overexpression of dominant-negative Akt. Moreover, the ability of EPO to override these checkpoints in cells expressing defective EPO-R mutants could be restored by overexpression of a constitutively active Akt. Thus, activation of a PI-3K/Akt signaling pathway is required for cytokine-dependent suppression of DNA-damage induced checkpoints. Together, these findings suggest a novel role for PI-3K/Akt pathways in the modulation of growth arrest responses to DNA damage in hematopoietic cells. (Blood. 2001;98:834-841)

A strategy for statistical Master Person Index linking.

A linking program used by Connecticut Healthcare Information Management and Exchange to maintain the Master Person Index for its large, state-wide patient data repository is being stretched beyond its limits by the growing size and complexity of the database. This paper presents the early work into developing a second-generation linking program. Like the original program, the new linker will use a unique multi-step process to allow effective linking of data from a large number of dissimilar data sources. The new linker will use parallel multi-processing to allow improved performance and scalability. These changes will also make possible more sophisticated statistical methods of defining link confidence. The system is implemented using a scalable collection of inexpensive, PC based systems running the Linux operating system, a freely available database engine, and the Java programming language.

Bile duct injuries, 1989-1993. A statewide experience. Connecticut Laparoscopic Cholecystectomy Registry.

OBJECTIVE: To review the incidence of major bile duct injuries (MBDI) during the shift from open (OC) to laparoscopic cholecystectomy (LC). DESIGN: Cohort analysis; minimum 15-month patient follow-up. SETTING: Acute care Connecticut hospitals. PATIENTS: Medical records of 30211 patients with cholecystectomy (OC or LC) reviewed; 47 cases of MBDI confirmed. MAIN OUTCOME MEASURE: Rate of MBDI. RESULTS: The incidence of MBDI in Connecticut hospitals rose from 0.04% in 1989 to 0.24% in 1991, then decreased to 0.11% in 1993. The increase was due to increased numbers of cholecystectomies and the initial increased risk of injury with LC. The 1990-through-1993 trend of decreasing incidence of LC MBDI was statistically significant (P=.02). By 1993, the difference between LC and OC was no longer significant (P=.81). Acute cholecystitis (odds ratio, 3.3) and gallstone pancreatitis (odds ratio, 3.6) increased the risk of MBDI during LC (P<.001). The LC MBDI more commonly were ductal excision or transections and often were not diagnosed intraoperatively. Intraoperative cholangiography facilitated intraoperative recognition and repair. Most patients (89%) underwent definitive management of the MBDI at the hospital of origin; of those, 5% required further interventions. CONCLUSIONS: Surgeries for acute cholecystitis and gallstone pancreatitis are associated with an increased risk for MBDI. Ductal anatomy, the timing of recognition of injury, and the method of repair dictate patient outcomes. Most patients are successfully managed at the hospital of origin, with good long-term results. Late bile duct strictures appear rare.

Outcome analysis of carotid endarterectomy in Connecticut: the impact of volume and specialty.

The purpose of this study was to define the relationship between the surgeon's operative experience and specialty and the postoperative morbidity and mortality of carotid endarterectomy. All patients undergoing carotid endarterectomy (code ICD-9CM 38.12) in Connecticut between October 1985 and September 1991 were retrospectively identified. A total of 3997 carotid endarterectomies were performed by 226 surgeons in four specialties: general, cardiac, vascular, and neurosurgery. Individual surgeon volume ranged from fewer than one per year to 27.5 per year (mean 2.9 carotid endarterectomies per year). Outcome was measured as a combined stroke and/or death percentage. The average combined stroke and/or death rate for the entire group was 4.9%. The combined stroke and/or death percentage was influenced significantly by the surgeon's annual volume. Surgeons who performed one or fewer carotid endarterectomies (43% of total surgeons) were 2.5 times more likely (p < 0.002) to have a poor postoperative outcome than those who performed 10 or more per year (9.3% of total surgeons). Overall there was a statistically significant correlation between a surgeon's annual volume and outcome, particularly for general surgeons.

Verification of information in a large medical database using linkages with external databases.

Efforts to utilize Uniform Hospital Discharge Data Sets (UHDDS) for epidemiological studies have been hampered by the limitations of those databases. The purpose of this paper is to illustrate that linking to external databases can provide the verification necessary to overcome many of those limitations. This method has dramatically altered study design at the Connecticut Hospital Research and Education Foundation and has provided an efficient method for specifying data collection weaknesses within the resident databases.

Comparison of mortality rates for open and closed cholecystectomy in the elderly: Connecticut statewide survey.

The objective was to determine the safety of laparoscopic cholecystectomy for patients 65 years of age and older with symptomatic uncomplicated chronic gallbladder disease by comparing the mortality rate with open cholecystectomy. Connecticut Hospital Information Management Exchange and the Connecticut Society of American Board of Surgeons established a Connecticut Laparoscopic Registry made up of 33 acute care hospitals. A cohort longitudinal retrospective statewide registry collected data mortality rates on all 2865 elderly patients undergoing open (OC) or closed (LC) cholecystectomy for uncomplicated chronic cholecystitis. A database was established and continuously monitored from October 1, 1988, to December 31, 1992. Seven hundred sixty-one patients over 65 years of age underwent open cholecystectomy for uncomplicated chronic cholecystectomy during fiscal year 1989, with a mortality rate of 1.4%. The mortality rate of a similar cohort of patients who underwent laparoscopic cholecystectomy during fiscal years 1991 and 1992 was 0.3% and 0.6%, respectively. The mortality rate was further broken down into age subsets 65-69, 70-79, and 80+. The prelaparoscopic era (FY 1989) age subsets were compared with those of the laparoscopic era (FY 1991 and 1992). A statistically significant reduction (p = 0.01) in mortality rate was noted in the 70-79 age group following laparoscopic surgery. Laparoscopic cholecystectomy in the elderly for the treatment of symptomatic, uncomplicated chronic cholecystitis is as safe if not safer than open cholecystectomy as measured by mortality rate.

The "Toward Excellence in Care" program: a statewide indicator project.

BACKGROUND: The "Toward Excellence in Care" program was launched by Connecticut hospitals and physicians in 1988 to develop and use quality-of-care indicators for use in quality improvement. METHODOLOGY: Data came primarily from the Connecticut Health Information Management and Exchange (CHIME) database, which contains discharge abstract information, UB (uniform billing)-82 information, and additional data elements, for all of Connecticut's 34 acute care hospitals. Linkages also occur with the state mortality database, the trauma registry, and with admission/discharge data within and across Connecticut hospitals. The "Toward Excellence in Care" program staff help the hospital use the data on indicator reports for quality improvement. EXAMPLE: On receiving a report on care for patients with acute myocardial infarction (AMI) a program representative summarized opportunities for improvement. The data were then disseminated to both the cardiology and the hospitalwide quality improvement staffs. Cardiologists conducted chart review on 100% of patients included in the last time-frame on the report (for example, fiscal year 1991). The quality improvement professional documented the system of care for an AMI patient. Recommended actions included adoption of a policy for emergency department administration of thrombolytic therapy before a cardiology consultation, and modification of the postcoronary care program. CONCLUSIONS: Progress in addressing four challenges-easing the burden of data collection on the hospitals, maximizing acceptance of information by hospitals and physicians, risk adjusting data to permit comparison of outcomes, and facilitating understanding of reports--is reflected in expanding use of the "Toward Excellence in Care" program.

"Where have all the children gone"? Inpatient pediatric care in Connecticut.

Admission of children to hospitals in Connecticut dropped precipitously from 1981 to 1991. Regionalization of pediatric inpatient care is happening without plan. Connecticut data show a change in case-mix of pediatric cases, especially in surgical services and child mental illness categories. Planning for pediatric inpatient services should include considerations of case-mix, cost, and especially, quality of care in general hospital pediatric units with very low volume.

Changes in Connecticut hospital use rates: have small-area variations been affected?

This paper examines the extent to which changes (prospective payment, alternative delivery systems, etc.) in the hospital environment and the general decline in hospital days affect small-area variations in hospital use rates for 18 selected diagnoses in nine hospital service areas in Connecticut. After adjusting for coding changes between DRGs, we found that variation across the service areas did not, in general, differ for any one of the years 1981-86. In one instance (cardiac catheterization), however, we found that a DRG-specific change in knowledge and technology decreased the extent of small-area variation for that diagnosis.

The National WIC Evaluation: evaluation of the Special Supplemental Food Program for Women, Infants, and Children. IV. Study methodology and sample characteristics in the longitudinal study of pregnant women, the study of children, and the food expenditures study.

The longitudinal study of pregnant women enrolled a national probability sample of 5,205 women first certified for WIC and 1,358 comparable low-income pregnant women in 174 WIC clinics located in 58 areas in the contiguous 48 states and in 55 prenatal clinics without WIC programs in counties with low program coverage. The women completed 24-h dietary recalls, histories of food expenditures, health care utilization, health and sociodemographic status, and anthropometric assessment. At late-pregnancy follow-up 3,967 WIC and 1043 control women were interviewed and 853 WIC and 762 control women completed 1-wk food expenditure diaries. Birth outcome was abstracted (from hospital records) for 3,863 WIC and 1058 control women. Anthropometry, dietary intake, health, and use of health services were related to WIC among 2,619 random low-income preschoolers. Psychological development was assessed in 526 children aged 4 and 5 y. Control women had higher income, education, and employment status; therefore, WIC program benefits probably were underestimated.