Leif E. Peterson

T-Cell Accumulation and Regulated on Activation, Normal T Cell Expressed and Secreted Upregulation in Adipose Tissue in Obesity

Background— Obesity is associated with chronic inflammation, which includes increased macrophage accumulation in adipose tissue (AT) and upregulation of chemokines and cytokines. T cells also play important roles in chronic inflammatory diseases such as atherosclerosis but have not been well studied in obesity. Methods and Results— Flow cytometric analysis showed higher numbers of T cells and macrophages in AT of diet-induced obese insulin-resistant male mice than in lean mice and obese females (P<0.05). RNase protection assay, ELISA, and flow cytometry indicated gender-dependent upregulation of mRNA and protein levels of regulated on activation, normal T cell expressed and secreted (RANTES) and its receptor CCR5 in AT of obese mice. Adipocytes, stromal/vascular cells from mouse AT, and human and murine adipocytes expressed RANTES. RANTES mRNA levels were negatively correlated with adiponectin in mouse AT. Adiponectin-deficient mice fed high-fat diet showed higher RANTES mRNA levels in AT than wild-type mice. Activated T cells coincubated with preadipocytes in vitro significantly suppressed preadipocyte-to-adipocyte differentiation. Obese humans with metabolic syndrome had higher mRNA levels of RANTES and CCR5 in subcutaneous AT than lean humans. RANTES and CCR5 mRNA levels were significantly higher in visceral than subcutaneous AT of morbidly obese humans. RANTES mRNA levels were positively correlated with CD3 and CD11b in human visceral AT. Conclusions— Obesity is associated with increased accumulation of T cells and macrophages in AT, which may play important roles in obesity-related disease by influencing preadipocyte/adipocyte functions. RANTES is an adipokine that is upregulated in AT by obesity in both mice and humans.

Spectrum of CHD7 Mutations in 110 Individuals with CHARGE Syndrome and Genotype-Phenotype Correlation

CHARGE syndrome is a well-established multiple-malformation syndrome with distinctive consensus diagnostic criteria. Characteristic associated anomalies include ocular coloboma, choanal atresia, cranial nerve defects, distinctive external and inner ear abnormalities, hearing loss, cardiovascular malformations, urogenital anomalies, and growth retardation. Recently, mutations of the chromodomain helicase DNA-binding protein gene CHD7 were reported to be a major cause of CHARGE syndrome. We sequenced the CHD7 gene in 110 individuals who had received the clinical diagnosis of CHARGE syndrome, and we detected mutations in 64 (58%). Mutations were distributed throughout the coding exons and conserved splice sites of CHD7. Of the 64 mutations, 47 (73%) predicted premature truncation of the protein. These included nonsense and frameshift mutations, which most likely lead to haploinsufficiency. Phenotypically, the mutation-positive group was more likely to exhibit cardiovascular malformations (54 of 59 in the mutation-positive group vs. 30 of 42 in the mutation-negative group; P=.014), coloboma of the eye (55 of 62 in the mutation-positive group vs. 30 of 43 in the mutation-negative group; P=.022), and facial asymmetry, often caused by seventh cranial nerve abnormalities (36 of 56 in the mutation-positive group vs. 13 of 39 in the mutation-negative group; P=.004). Mouse embryo whole-mount and section in situ hybridization showed the expression of Chd7 in the outflow tract of the heart, optic vesicle, facio-acoustic preganglion complex, brain, olfactory pit, and mandibular component of the first branchial arch. Microarray gene-expression analysis showed a signature pattern of gene-expression differences that distinguished the individuals with CHARGE syndrome with CHD7 mutation from the controls. We conclude that cardiovascular malformations, coloboma, and facial asymmetry are common findings in CHARGE syndrome caused by CHD7 mutation.

Characterization of BRCA1 and BRCA2 Mutations in a Large United States Sample

PURPOSE An accurate evaluation of the penetrance of BRCA1 and BRCA2 mutations is essential to the identification and clinical management of families at high risk of breast and ovarian cancer. Existing studies have focused on Ashkenazi Jews (AJ) or on families from outside the United States. In this article, we consider the US population using the largest US-based cohort to date of both AJ and non-AJ families. METHODS We collected 676 AJ families and 1,272 families of other ethnicities through the Cancer Genetics Network. Two hundred eighty-two AJ families were population based, whereas the remainder was collected through counseling clinics. We used a retrospective likelihood approach to correct for bias induced by oversampling of participants with a positive family history. Our approach takes full advantage of detailed family history information and the Mendelian transmission of mutated alleles in the family. RESULTS In the US population, the estimated cumulative breast cancer risk at age 70 years was 0.46 (95% CI, 0.39 to 0.54) in BRCA1 carriers and 0.43 (95% CI, 0.36 to 0.51) in BRCA2 carriers, whereas ovarian cancer risk was 0.39 (95% CI, 0.30 to 0.50) in BRCA1 carriers and 0.22 (95% CI, 0.14 to 0.32) in BRCA2 carriers. We also reported the prospective risks of developing cancer for cancer-free carriers in 10-year age intervals. We noted a rapid decrease in the relative risk of breast cancer with age and derived its implication for genetic counseling. CONCLUSION The penetrance of BRCA mutations in the United States is largely consistent with previous studies on Western populations given the large CIs on existing estimates. However, the absolute cumulative risks are on the lower end of the spectrum.

Space Radiation Cancer Risks and Uncertainties for Mars Missions

Abstract Cucinotta, F. A., Schimmerling, W., Wilson, J. W., Peterson, L. E., Badhwar, G. D., Saganti, P. B. and Dicello, J. F. Space Radiation Cancer Risks and Uncertainties for Mars Missions. Radiat. Res. 156, 682–688 (2001). Projecting cancer risks from exposure to space radiation is highly uncertain because of the absence of data for humans and because of the limited radiobiology data available for estimating late effects from the high-energy and charge (HZE) ions present in the galactic cosmic rays (GCR). Cancer risk projections involve many biological and physical factors, each of which has a differential range of uncertainty due to the lack of data and knowledge. We discuss an uncertainty assessment within the linear-additivity model using the approach of Monte Carlo sampling from subjective error distributions that represent the lack of knowledge in each factor to quantify the overall uncertainty in risk projections. Calculations are performed using the space radiation environment and transport codes for several Mars mission scenarios. This approach leads to estimates of the uncertainties in cancer risk projections of 400–600% for a Mars mission. The uncertainties in the quality factors are dominant. Using safety standards developed for low-Earth orbit, long-term space missions (>90 days) outside the Earths magnetic field are currently unacceptable if the confidence levels in risk projections are considered. Because GCR exposures involve multiple particle or δ-ray tracks per cellular array, our results suggest that the shape of the dose response at low dose rates may be an additional uncertainty for estimating space radiation risks.

GENE EXPRESSION CHANGES IN MOUSE BRAIN AFTER EXPOSURE TO LOW-DOSE IONIZING RADIATION

Purpose: To characterize the cellular functions associated with the altered transcript profiles of mouse brain exposed to low‐dose in vivo gamma‐irradiation. Materials and methods: Cerebral RNA was isolated at 30 min and 4 h after whole‐body irradiation at 0.1 or 2 Gy, hybridized to random oligonucleotide arrays, and evaluated for time and dose–response patterns by multifactorial analyses. Results: Brain irradiation modulated the expression patterns of 1574 genes, of which 855 showed more than 1.5‐fold variation. about 30% of genes showed dose‐dependent variations, including genes exclusively affected by 0.1 Gy. About 60% of genes showed time‐dependent variation with more genes affected at 30 min than at 4 h. Early changes involved signal transduction, ion regulation and synaptic signalling. Later changes involved metabolic functions including myelin and protein synthesis. Low‐dose radiation also modulated the expression of genes involved in stress response, cell‐cycle control and DNA synthesis/repair. Conclusions: Doses of 0.1 Gy induced changes in gene expression that were qualitatively different from those at 2 Gy. The findings suggest that low‐dose irradiation of the brain induces the expression of genes involved in protective and reparative functions, while down‐modulating genes involved in neural signalling activity.

The Coronary Artery Calcium Score and Stress Myocardial Perfusion Imaging Provide Independent and Complementary Prediction of Cardiac Risk

OBJECTIVES This study sought to examine the relationship between coronary artery calcium score (CACS) and single-photon emission computed tomography (SPECT) results for predicting the short- and long-term risk of cardiac events. BACKGROUND The CACS and SPECT results both provide important prognostic information. It is unclear whether integrating these tests will better predict patient outcome. METHODS We followed-up 1,126 generally asymptomatic subjects without previous cardiovascular disease who had a CACS and stress SPECT scan performed within a close time period (median 56 days). The median follow-up was 6.9 years. End points analyzed were total cardiac events and all-cause death/myocardial infarction (MI). RESULTS An abnormal SPECT result increased with increasing CACS from <1% (CACS < or =10) to 29% (CACS >400) (p < 0.001). Total cardiac events and death/MI also increased with increasing CACS and abnormal SPECT results (p < 0.001). In subjects with a normal SPECT result, CACS added incremental prognostic information, with a 3.55-fold relative increase for any cardiac event (2.75-fold for death/MI) when the CACS was severe (>400) versus minimal (< or =10). Separation of the survival curves occurred at 3 years after initial testing for all cardiac events and at 5 years for death/MI. CONCLUSIONS The CACS and SPECT findings are independent and complementary predictors of short- and long-term cardiac events. Despite a normal SPECT result, a severe CACS identifies subjects at high long-term cardiac risk. After a normal SPECT result, our findings support performing a CACS in patients who are at intermediate or high clinical risk for coronary artery disease to better define those who will have a high long-term risk for adverse cardiac events.

Impact of Contrast Echocardiography on Evaluation of Ventricular Function and Clinical Management in a Large Prospective Cohort

OBJECTIVES The aim of this study was to evaluate the impact of echocardiographic contrast utilization on patient diagnosis and management. BACKGROUND Contrast echocardiography (CE) has improved visualization of endocardial borders. However, its impact on patient management has not been evaluated previously. METHODS We prospectively enrolled 632 consecutive patients with technically difficult echocardiographic studies who received intravenous contrast (Definity, Lantheus Medical Imaging, Billerica, Massachusetts). Quality of studies, number of left ventricular (LV) segments visualized, estimated ejection fraction, presence of apical thrombus, and management decisions were compared before and after contrast. RESULTS After CE, the percent of uninterpretable studies decreased from 11.7% to 0.3% and technically difficult studies decreased from 86.7% to 9.8% (p < 0.0001). Before contrast, 11.6 +/- 3.3 of 17 LV segments were seen, which improved after CE to 16.8 +/- 1.1 (p < 0.0001). An LV thrombus was suspected in 35 patients and was definite in 3 patients before CE. After contrast, only 1 patient had a suspected thrombus, and 5 additional patients with thrombus were identified (p < 0.0001). A significant impact of CE on management was observed: additional diagnostic procedures were avoided in 32.8% of patients and drug management was altered in 10.4%, with a total impact (procedures avoided, change in drugs, or both) observed in 35.6% of patients. The impact of contrast increased with worsening quality of nonenhanced study, the highest being in intensive care units. A cost-benefit analysis showed a significant savings using contrast (

Low-Dose Irradiation Alters the Transcript Profiles of Human Lymphoblastoid Cells Including Genes Associated with Cytogenetic Radioadaptive Response

122/patient). CONCLUSIONS The utilization of CE in technically difficult cases improves endocardial visualization and impacts cardiac diagnosis, resource utilization, and patient management.

Integrating rapid diagnostics and antimicrobial stewardship improves outcomes in patients with antibiotic-resistant Gram-negative bacteremia

Abstract Coleman, M. A., Yin, E., Peterson, L. E., Nelson, D., Sorensen, K., Tucker, J. D. and Wyrobek, A. J. Low-Dose Irradiation Alters the Transcript Profiles of Human Lymphoblastoid Cells Including Genes Associated with Cytogenetic Radioadaptive Response. Radiat. Res. 164, 369–382 (2005). Low-dose ionizing radiation alters the gene expression profiles of mammalian cells, yet there is little understanding of the underlying cellular mechanisms responsible for these changes or of their consequences for genomic stability. We investigated the cytogenetic adaptive response of human lymphoblastoid cell lines exposed to 5 cGy (priming dose) followed by 2 Gy (challenge dose) compared to cells that received a single 2-Gy dose to (a) determine how the priming dose influences subsequent gene transcript expression in reproducibly adapting and non-adapting cell lines, and (b) identify gene transcripts that are associated with reductions in the magnitude of chromosomal damage after the challenge dose. The transcript profiles were evaluated using oligonucleotide arrays and RNA obtained 4 h after the challenge dose. A set of 145 genes (false discovery rate = 5%) with transcripts that were affected by the 5-cGy priming dose fell into two categories: (a) a set of common genes that were similarly modulated by the 5-cGy priming dose irrespective of whether the cells subsequently adapted or not and (b) genes with differential transcription in accordance with the cell lines that showed either adaptive or non-adaptive outcomes. The common priming-dose response genes showed up-regulation for protein synthesis genes and down-regulation of metabolic and signal transduction genes (>10-fold differences). The genes associated with subsequent adaptive and non-adaptive outcomes involved DNA repair, stress response, cell cycle control and apoptosis. Our findings support the importance of TP53-related functions in the control of the low-dose cytogenetic radioadaptive response and suggest that certain low-dose-induced alterations in cellular functions are predictive for the risk of subsequent genomic damage.

Genomic segmental polymorphisms in inbred mouse strains

BACKGROUND An intervention for Gram-negative bloodstream infections that integrated mass spectrometry technology for rapid diagnosis with antimicrobial stewardship oversight significantly improved patient outcomes and reduced hospital costs. As antibiotic resistance rates continue to grow at an alarming speed, the current study was undertaken to assess the impact of this intervention in a challenging patient population with bloodstream infections caused by antibiotic-resistant Gram-negative bacteria. METHODS A total of 153 patients with antibiotic-resistant Gram-negative bacteremia hospitalized prior to the study intervention were compared to 112 patients treated post-implementation. Outcomes assessed included time to optimal antibiotic therapy, time to active treatment when inactive, hospital and intensive care unit length of stay, all-cause 30-day mortality, and total hospital expenditures. RESULTS Integrating rapid diagnostics with antimicrobial stewardship improved time to optimal antibiotic therapy (80.9 h in the pre-intervention period versus 23.2 h in the intervention period, P < 0.001) and effective antibiotic therapy (89.7 h versus 32 h, P < 0.001). Patients in the pre-intervention period had increased duration of hospitalization compared to those in the intervention period (23.3 days versus 15.3 days, P = 0.0001) and longer intensive care unit length of stay (16 days versus 10.7 days, P = 0.008). Mortality among patients during the intervention period was lower (21% versus 8.9%, P = 0.01) and our study intervention remained a significant predictor of survival (OR, 0.3; 95% confidence interval [CI], 0.12-0.79) after multivariate logistic regression. Mean hospital costs for each inpatient survivor were reduced