Sumihiro Suzuki

RLIP76 in Defense of Radiation Poisoning

PURPOSE To determine the role of RLIP76 in providing protection from radiation and chemotherapy. In the present report, we used RLIP76 to refer to both the mouse (Ralbp1) and the human (RLIP76) 76-kDa splice variant proteins (RLIP76) for convenience and to avoid confusion. In other reports, Ralbp1 refers to the mouse enzyme (encoded by the Ralbp1 gene), which is structurally and functionally homologous to RLIP76, the human protein encoded by the human RALBP1 gene. METHODS AND MATERIALS Median lethal dose studies were performed in RLIP76(-/-) and RLIP76(+/+) C57B mice after treatment with a single dose of RLIP76 liposomes 14 h after whole body radiation. The radiosensitivity of the cultured mouse embryonic fibroblasts and the effects of buthionine sulfoximine (BSO), amifostine, c-jun N-terminal kinase (JNK), protein kinase B (Akt), and MAPK/ERK kinase (MEK) were determined by colony-forming assays. Glutathione-linked enzyme activities were measured by spectrophotometric assays, glutathione by dithiobis-2-nitrobenzoic acid (DTNB), lipid hydroperoxides by iodometric titration, and aldehydes and metabolites by thiobarbitauric acid reactive substances and liquid chromatography-mass spectrometry (LCMS). RESULTS RLIP76(-/-) mice were significantly more sensitive to radiation than were the wild-type, and RLIP76 liposomes prolonged survival in a dose-dependent manner in both genotypes. The levels of 4-hydroxynonenal and glutathione-conjugate of 4-hydroxynonenal were significantly increased in RLIP76(-/-) tissues compared with RLIP76(+/+). RLIP76(-/-) mouse embryonic fibroblasts were markedly more radiosensitive than RLIP76(+/+) mouse embryonic fibroblasts, despite increased glutathione levels in the former. RLIP76 augmentation had a remarkably greater protective effect compared with amifostine. The magnitude of effects of RLIP76 loss on radiation sensitivity was greater than those caused by perturbations of JNK, MEK, or Akt, and the effects of RLIP76 loss could not be completely compensated for by modulating the levels of these signaling proteins. CONCLUSION The results of our study have shown that RLIP76 plays a central role in radiation resistance.

Glutathione-Conjugate Transport by RLIP76 Is Required for Clathrin-Dependent Endocytosis and Chemical Carcinogenesis

Targeted depletion of the RALBP1-encoded 76-kDa splice variant, RLIP76, causes marked and sustained regression of human xenografts of lung, colon, prostate, and kidney cancers without toxicity in nude mouse models. We proposed that the remarkable efficacy and broad spectrum of RLIP76-targeted therapy is because its glutathione-conjugate (GS-E) transport activity is required for clathrin-dependent endocytosis (CDE), which regulates all ligand-receptor signaling, and that RLIP76 is required not only for survival of cancer cells but also for their very existence. We studied RLIP76 mutant proteins and the functional consequences of their expression into RLIP76−/− MEFs, identified key residues for GS-E binding in RLIP76, established the requirement of RLIP76-mediated GS-E transport for CDE, and showed a direct correlation between GS-E transport activities with CDE. Depletion of RLIP76 nearly completely blocked signaling downstream of EGF in a CDE-dependent manner and Wnt5a signaling in a CDE-independent manner. The seminal prediction of this hypothesis—RLIP76−/− mice will be deficient in chemical neoplasia—was confirmed. Benzo[a]pyrene, dimethylbenzanthracene, and phorbol esters are ineffective in causing neoplasia in RLIP76−/−. PMA-induced skin carcinogenesis in RLIP76+/+ mouse was suppressed completely by depletion of either PKCα or RLIP76 by siRNA or antisense and could be restored by topical application of RLIP76 protein in RLIP76−/− mouse skin. Likewise, chemical pulmonary carcinogenesis was absent in female and nearly absent in male RLIP76−/− mice. In RLIP76−/− mice, p53, p38, and JNK activation did not occur in response to either carcinogen. Our findings show a fundamental role of RLIP76 in chemical carcinogenesis. Mol Cancer Ther; 10(1); 16–28. ©2011 AACR.

Rural-urban disparities in quality of life among patients with COPD.

PURPOSE Limited evidence in the United States suggests that among patients with chronic obstructive pulmonary disease (COPD), rural residence is associated with higher hospitalization rates and increased mortality. However, little is known about the reasons for these disparities. This studys purpose was to describe the health status of rural versus urban residence among patients with COPD and to examine factors associated with differences between these 2 locations. METHODS This was a cross-sectional study of baseline data from a representative sample of patients with COPD enrolled in a clinical trial. Rural-urban residence was determined from ZIP code. Health status was measured using the SF-12 and health care utilization. Independent sample t-tests, chi-square tests, and multiple linear and logistic regressions were performed to examine differences between rural and urban patients. FINDINGS Rural residence was associated with poorer health status and higher health care utilization. Among rural patients unadjusted physical functioning scores were lower on the SF-12 (30.22 vs 33.49; P = .005) that persisted after adjustment for potential confounders (β = -2.35; P = .04). However, after further adjustment for social and psychological factors only the body-mass index, airflow obstruction, dyspnea, and exercise (BODE) index was significantly associated with health status. CONCLUSIONS In this representative sample of patients with COPD rural residence was associated with worse health status, primarily associated with greater impairment as measured by BODE index. While rural patients reported a higher dose of smoking, a number of other unmeasured factors associated with rural residence may contribute to these disparities.

GEOGRAPHIC DISPARITY IN COPD HOSPITALIZATION RATES AMONG THE TEXAS POPULATION

BACKGROUND Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality caused by cigarette smoking and other environmental exposures. While variation in exposures may affect COPD morbidity and mortality, little is known about geographic variation, a surrogate of exposures. The objective of this manuscript is to explore the geographic variation in COPD hospitalization rates among the Texas population in 2006. METHODS The study population consisted of all Texas residents with COPD hospitalizations in the 2006 Texas Health Care Information Council (THCIC) data. County population estimates stratified by race, age, and gender were linked to THCIC data to calculate county level COPD hospitalization rates per 100,000 admissions. The data were merged with Urban Influence Codes by county, and metropolitan status was determined by United States Department of Agriculture (USDA) criteria. Variation in COPD hospitalization rates were analyzed using Poisson Regression. RESULTS Overall, non Hispanic (NH) Whites had the highest rate of hospitalization, followed by NH Blacks (rate ratio=0.42) and Hispanics (RR=0.17), the 65+ age category had the highest rates of hospitalization. In the metropolitan counties COPD hospitalization rates were lower than non-metropolitan counties, however in metropolitan counties the rates of hospitalization were significantly higher (p<0.0001) in females compared to males. The rates were significantly higher in males in public health regions 10 and 11, which are predominantly non-metropolitan counties. CONCLUSIONS In Texas there is substantial geographic variation in hospitalization rates associated with gender and race/ethnicity. Other factors that may contribute to the variation and require further investigation include differences in smoking and exposure to other environmental risk factors, access to primary care, medical practice patterns, and coding practices.

M2b Monocytes Provoke Bacterial Pneumonia and Gut Bacteria–Associated Sepsis in Alcoholics

Chronic alcohol consumption markedly impairs host antibacterial defense against opportunistic infections. γ-irradiated NOD-SCID IL-2Rγnull mice inoculated with nonalcoholic PBMCs (control PBMC chimeras) resisted Klebsiella pneumonia and gut bacteria-associated sepsis, whereas the chimeras created with alcoholic PBMCs (alcoholic PBMC chimeras) were very susceptible to these infections. M1 monocytes (IL-12+IL-10−CD163−CD14+ cells), major effector cells in antibacterial innate immunity, were not induced by a bacterial Ag in alcoholic PBMC cultures, and M2b monocytes (CCL1+CD163+CD14+ cells), which predominated in alcoholic PBMCs, were shown to be inhibitor cells on the Ag-stimulated monocyte conversion from quiescent monocytes to M1 monocytes. CCL1, which functions to maintain M2b macrophage properties, was produced by M2b monocytes isolated from alcoholic PBMCs. These M2b monocytes reverted to quiescent monocytes (IL-12−IL-10−CCL1−CD163−CD14+ cells) in cultures supplemented with CCL1 antisense oligodeoxynucleotide, and the subsequent quiescent monocytes easily converted to M1 monocytes under bacterial Ag stimulation. Alcoholic PBMC chimeras treated with CCL1 antisense oligodeoxynucleotide were resistant against pulmonary infection by K. pneumoniae and sepsis stemming from enterococcal translocation. These results indicate that a majority of monocytes polarize to an M2b phenotype in association with alcohol abuse, and this polarization contributes to the increased susceptibility of alcoholics to gut and lung infections. Bacterial pneumonia and gut bacteria-associated sepsis, frequently seen in alcoholics, can be controlled through the polarization of macrophage phenotypes.

M2b Macrophage Elimination and Improved Resistance of Mice with Chronic Alcohol Consumption to Opportunistic Infections

Alcohol abuse was found to predispose persons to opportunistic infections. In this study, we tried to improve the host antibacterial resistance of chronic alcohol-consuming (CAC) mice to opportunistic infections. Bactericidal macrophages with functions to produce IL-12 and to express mRNAs for CXCL9 and inducible nitric oxide synthase (M1 macrophages) were characterized as the main effector cells in host antibacterial innate immunities against infections with opportunistic pathogens. However, CAC mice were found to be carriers of M2b macrophages [macrophages with functions to produce IL-10 and to express mRNAs for CD163, chemokine ligand (CCL)1, and LIGHT (homologous to lymphotoxin, exhibits inducible expression, competes with herpes simplex virus glycoprotein D for high-voltage electron microscopy on T cells)], which were inhibitory on macrophage conversion from resident macrophages to M1 macrophages. Under treatment with CCL1 antisense oligodeoxynucleotides, a specific inhibitor of M2b macrophages, CAC mouse macrophages reverted to resident macrophages, and M1 macrophages were induced by a bacterial antigen from macrophages of CAC mice that were previously treated with the oligodeoxynucleotides. Opportunistic infections (enterococcal translocation and Klebsiella pneumonia) in CAC mice were completely controlled by CCL1 antisense oligodeoxynucleotides. These results indicate that certain opportunistic infections in alcoholics are controllable through the modulation of M2b macrophages.

Alcohol mixed with energy drink: use may be a consequence of heavy drinking

AIMS In recent years, studies have indicated that consumers of alcohol mixed with energy drink (AmED) are more likely to drink heavily and experience more negative consequences than consumers who avoid these beverages. Although researchers have identified a number of plausible hypotheses that explain how alcohol-energy drink co-ingestion could cause greater alcohol consumption, there has been no postulation about reverse causal relations. This paper identifies several plausible hypotheses for the observed associations between AmED consumption and greater alcohol consumption, and provides initial evidence for one such hypothesis suggesting that heavy drinking may be a determinant of AmED use. METHOD Data collected from 511bar patrons were used to examine the plausibility of one of the proposed hypotheses, i.e., AmED is an artifact of heavy drinking. Associations between the consumption of an assortment of alcoholic beverage types and total alcohol consumption were examined at the event-level, to assess whether AmED is uniquely related with greater alcohol consumption. RESULTS Increased alcohol consumption was associated with greater odds of consuming most alcoholic beverage types; this association was not unique to AmED. CONCLUSIONS Results support the overlooked hypothesis that AmED use is an artifact of heavy drinking. Thus, AmED consumption may be a consequence or marker of heavier drinking. Much of the existing research on alcoholic beverage types is limited in its ability to implicate any specific type of drink, including AmED, as a cause of increased alcohol consumption and related harm. More rigorous study designs are needed to examine causal relationships.

Letter to the editor in regard to Peacock, Bruno, and Martin (2012): "the subjective physiological, psychological, and behavioral risk-taking consequences of alcohol and energy drink co-ingestion": misleading results and unjustified conclusions.

THE CONCLUSIONS PUBLISHED in Alcoholism: Clinical and Experimental Research (2012;36:2008– 2015) by Peacock and colleagues are not justified, at least as explained in their paper. The authors conclude that alcohol mixed with energy drink, or AmED-drinking sessions, are associated with less involvement in risk behavior because individuals were observed to be less likely to engage in these behaviors during AmED sessions compared with alcoholonly drinking sessions in the past 6 months. However, AmED sessions were far less frequent than alcohol-only drinking sessions. Therefore, the relationship between type of drinking session and engagement in risk behaviors is distorted by the large difference in the total number of AmED and alcohol-only drinking sessions, resulting in spurious effect estimates. Not accounting for this difference in the analysis produced misleading results, which in turn, led to conclusions that cannot be supported by the data. A growing body of literature has observed that consumers of AmED engage in more risk-taking behavior while drinking and experience more negative alcohol-related consequences than individuals who do not consume AmED (Brache and Stockwell, 2011; O’Brien et al., 2008; Thombs et al., 2010). The recent study by Peacock and colleagues (2012) sought to discern whether (i) AmED use, or caffeinated alcohol consumption, prompts increased involvement in risk behavior during drinking sessions or (ii) AmED users represent a subpopulation of young adults who have a heightened propensity or proneness for engaging in multiple risk behaviors. These alternative hypotheses are at the center of the current debate about the need to regulate caffeinated alcohol use. Unfortunately, weaknesses of the Peakcock and colleagues study further muddle our understanding of these important issues. Others have already begun citing Peacock and colleagues (2012) as a within-participant study providing evidence of no relationship (Howland and Rohsenow, 2013) or a protective relationship (Pennay and Lubman, 2012) between AmED consumption and engagement in risk behavior. Unfortunately, due to the limitations of the study design and analysis plan, this paper, as written, cannot provide a definitive answer to that question. Any interpretation of the reported findings needs to be conditioned on severe, fundamental limitations. The study design raises several serious concerns. First, the online survey instrument has 303 items, which was reported to be completed by the participants in 10 to 30 minutes. This indicates that on average, respondents took between 2 and 6 seconds to read, comprehend, and respond to each survey item. Given such quick response times to a relatively long survey, questions need to be raised about whether participants responded indiscriminately to survey items merely for a chance to win an Apple iPad2 . Second, during these relatively rapid responses to survey items, respondents were asked to form judgments about whether their engagement in each risk behavior was due to their consumption of AmED. Serious questions can be raised about the validity of survey items that rely on the ability of respondents to correctly attribute their involvement in risk behavior to their AmED consumption (Wood et al., 1997). Such an approach may result in an overestimate of the association if respondents incorrectly attribute their risk behavior to AmED consumption. Conversely, respondent assessment of their attributions could also lead to an underestimate if they incorrectly failed to attribute their risk behavior to AmED consumption. Use of these attribution measures elicited subjective responses that contribute little to the science on caffeinated alcohol consumption. From the Department of Behavioral and Community Health (MER, DLT), University of North Texas Health Science Center, Fort Worth, Texas. Department of Biostatistics (SS), University of North Texas Health Science Center, Fort Worth, Texas. Received for publicationMarch 12, 2013; accepted April 12, 2013. Reprint requests: Matthew E. Rossheim, MPH, Department of Behavioral and Community Health, School of Public Health, 3500 Camp Bowie Blvd., UNT Health Science Center, Fort Worth, TX 76107-2699; Tel.: 941-323-0778; Fax: 817-735-2619; E-mail: matthew.rossheim@live. unthsc.edu Copyright© 2013 by the Research Society on Alcoholism.

Safety-net facilities and hospitalization rates of chronic obstructive pulmonary disease: a cross-sectional analysis of the 2007 Texas Health Care Information Council inpatient data

Purpose Geographic disparities in hospitalization rates for chronic obstructive pulmonary disease (COPD) have been observed in Texas. However, little is known about the sources of these variations. The purpose of this manuscript is to further explore the geographic disparity of COPD hospitalization rates in Texas by examining county-level factors affecting access to care. Patients and methods The study is a cross-sectional analysis of the 2007 Texas Health Care Information Council, Texas, demographer population projections and the 2009 Area Resource File (ARF). The unit of analysis was county-specific hospitalization rate, calculated as the number of discharges of county residents divided by county-level population estimates. Indicators of access to care included: type of safety-net facility and number of pulmonary specialists in a county. Safety-net facilities of interest were federally qualified health centers (FQHCs) and rural health clinics (RHCs). Results There was a significant difference (P < 0.05) in hospitalization rates according to health center presence. Counties with only FQHCs had the lowest COPD hospitalization rate (132 per 100,000 observations), and counties with only RHCs had the highest hospitalization rate (229 per 100,000 observations). The presence of a pulmonary specialist was associated with a significant decrease (25%) in hospitalization rates among counties with only FQHCs. Conclusion In Texas, counties with only FQHCs were associated with lower COPD hospitalization rates. The presence of a RHC alone may be insufficient to decrease hospitalizations from COPD. There are a number of factors that may contribute to these variations in hospitalization rates, such as racial/ethnic distribution, types and quality of services provided, and the level of rurality, which creates greater distances to care and lower concentration of hospitals and pulmonary specialists.

Self-efficacy to drive while intoxicated: insights into the persistence of alcohol-impaired driving

BACKGROUND Scant research has examined event-level risk factors for impaired driving in natural drinking settings. This study assessed driving self-efficacy among intoxicated individuals to better understand decision-making about alcohol-impaired driving at night after exiting on-premise drinking establishments. METHODS Interview and breath test data were collected from bar patrons (n = 512) exiting 2 college bar districts in Florida and Texas. RESULTS Results from a multivariable linear regression model indicated that self-efficacy to drive while intoxicated was more strongly associated with situational variables, that is, perceived drunkenness and self-estimated blood alcohol concentration than patron traits, that is, past-year history of drinking, risk proneness, and sex. A large proportion of bar patrons, particularly men, expressed confidence in their ability to drive, despite being highly intoxicated. Moreover, the majority of legally intoxicated patrons who were confident in their ability to drive were aware of their high level of intoxication. CONCLUSIONS Emphasis should be placed on the enactment and enforcement of policies and laws to prevent alcohol-impaired driving.