A multivariable analysis is the most popular approach when investigating
associations between risk factors and disease. However, efficiency of multivariable
analysis highly depends on correlation structure among predictive variables. When the
covariates in the model are not independent one another, collinearity/multicollinearity
problems arise in the analysis, which leads to biased estimation. This work aims to
perform a simulation study with various scenarios of different collinearity structures to
investigate the effects of collinearity under various correlation structures amongst
predictive and explanatory variables and to compare these results with existing guidelines
to decide harmful collinearity. Three correlation scenarios among predictor variables are
considered: (1) bivariate collinear structure as the most simple collinearity case, (2)
multivariate collinear structure where an explanatory variable is correlated with two
other covariates, (3) a more realistic scenario when an independent variable can be
expressed by various functions including the other variables.
multicollinearity effect; multivariable models; collinearity structure; simulation study
Little is known about the molecular pathways regulating poor differentiation and invasion of head and neck squamous cell carcinoma (HNSCC). In the present study, we aimed to determine the role of MDA-9/Syntenin, a metastasis associated molecule in HNSCC tumorigenesis. Elevated MDA-9/Syntenin expression was evident in 67% (54/81) primary HNSCC tumors (p=0.001-0.002) and 69% (9/13) pre-neoplastic tissues (p=0.02-0.03). MDA-9/Syntenin overexpression was associated with the stage (p=0.001), grade (p=0.001) and lymph node metastasis (p=0.0001). Silencing of MDA-9/Syntenin in 3 poorly differentiated HNSCC cell lines induced squamous epithelial cell differentiation, disrupted angiogenesis and reduced tumor growth in vitro and in vivo. We confirmed SPRR1B and VEGFR1 as the key molecular targets of MDA-9/Syntenin on influencing HNSCC differentiation and angiogenesis respectively. MDA-9/Syntenin disrupted SPRR1B expression interacting through its PDZ1 domain and altered VEGFR1 expression in vitro and in vivo. VEGFR1 co-localized with MDA-9/Syntenin in HNSCC cell lines and primary tumor. Downregulation of growth regulatory molecules CyclinD1, CDK4, STAT3, PI3K and CTNNB1 was also evident in the MDA-9/Syntenin depleted cells, which was reversed following over-expression of MDA-9/Syntenin in immortalized oral epithelial cells. Our results suggest that early induction of MDA-9/Syntenin expression influences HNSCC progression and should be further evaluated for potential biomarker development.
Head and neck suqamous cell carcinoma; MDA-9/Syntenin; differentiation; SPRR1B; VEGFR1
The main purpose of this study was to model and analyze the dynamics of cervical cancer mortality rates for African American (Black) and White women residing in 13 states located in the eastern half of the United States of America from 1975 through 2010.
The cervical cancer mortality rates of the Surveillance, Epidemiology, and End Results (SEER) were used to model and analyze the dynamics of cervical cancer mortality. A longitudinal hyperbolastic mixed-effects type II model was used to model the cervical cancer mortality data and SAS PROC NLMIXED and Mathematica were utilized to perform the computations.
Despite decreasing trends in cervical cancer mortality rates for both races, racial disparities in mortality rates still exist. In all 13 states, Black women had higher mortality rates at all times. The degree of disparities and pace of decline in mortality rates over time differed among these states. Determining the paces of decline over 36 years showed that Tennessee had the most rapid decline in cervical cancer mortality for Black women, and Mississippi had the most rapid decline for White Women. In contrast, slow declines in cervical cancer mortality were noted for Black women in Florida and for White women in Maryland.
In all 13 states, cervical cancer mortality rates for both racial groups have fallen. Disparities in the pace of decline in mortality rates in these states may be due to differences in the rates of screening for cervical cancers. Of note, the gap in cervical cancer mortality rates between Black women and White women is narrowing.
The conditionally replicative adenovirus Ad5/3-Δ24 has a type-3 knob incorporated into the type-5 fiber that facilitates enhanced ovarian cancer infectivity. Preclinical studies have shown that Ad5/3-Δ24 achieves significant oncolysis and antitumor activity in ovarian cancer models. The purpose of this study was to evaluate in a Phase I trial the feasibility and safety of intraperitoneal (IP) Ad5/3-Δ24 in recurrent ovarian cancer patients.
Eligible patients were treated with IP Ad5/3-Δ24 for 3 consecutive days in one of three dose cohorts ranging 1 × 1010–1 × 1012 vp. Toxicity was assessed utilizing CTC grading and efficacy with RECIST. Ascites, serum, and other samples were obtained to evaluate gene transfer, generation of wildtype virus, viral shedding, and antibody response.
Nine of 10 patients completed treatment per protocol. A total of 15 vector-related adverse events were experienced in 5 patients. These events included fever or chills, nausea, fatigue, and myalgia. All were grade 1–2 in nature, transient, and medically managed. Of the 8 treated patients evaluable for response, six patients had stable disease and 2 patients had progressive disease. Three patients had decreased CA-125 from pretreatment levels one month after treatment. Ancillary biologic studies indicated Ad5/3-Δ24 replication in patients in the higher dose cohorts. All patients experienced an anti-adenoviral neutralizing antibody effect.
This study suggests the feasibility and safety of a serotype chimeric infectivity-enhanced CRAd, Ad5/3-Δ24, as a potential therapeutic option for recurrent ovarian cancer patients.
CRAd; gene therapy; infectivity-enhanced adenoviral vectors; ovarian cancer
N-Myc Interactor is an inducible protein whose expression is compromised in advanced stage breast cancer. Downregulation of NMI, a gatekeeper of epithelial phenotype, in breast tumors promotes mesenchymal, invasive and metastatic phenotype of the cancer cells. Thus the mechanisms that regulate expression of NMI are of potential interest for understanding the etiology of breast tumor progression and metastasis.
Web based prediction algorithms were used to identify miRNAs that potentially target the NMI transcript. Luciferase reporter assays and western blot analysis were used to confirm the ability of miR-29 to target NMI. Quantitive-RT-PCRs were used to examine levels of miR29 and NMI from cell line and patient specimen derived RNA. The functional impact of miR-29 on EMT phenotype was evaluated using transwell migration as well as monitoring 3D matrigel growth morphology. Anti-miRs were used to examine effects of reducing miR-29 levels from cells. Western blots were used to examine changes in GSK3β phosphorylation status. The impact on molecular attributes of EMT was evaluated using immunocytochemistry, qRT-PCRs as well as Western blot analyses.
Invasive, mesenchymal-like breast cancer cell lines showed increased levels of miR-29. Introduction of miR-29 into breast cancer cells (with robust level of NMI) resulted in decreased NMI expression and increased invasion, whereas treatment of cells with high miR-29 and low NMI levels with miR-29 antagonists increased NMI expression and decreased invasion. Assessment of 2D and 3D growth morphologies revealed an EMT promoting effect of miR-29. Analysis of mRNA of NMI and miR-29 from patient derived breast cancer tumors showed a strong, inverse relationship between the expression of NMI and the miR-29. Our studies also revealed that in the absence of NMI, miR-29 expression is upregulated due to unrestricted Wnt/β-catenin signaling resulting from inactivation of GSK3β.
Aberrant miR-29 expression may account for reduced NMI expression in breast tumors and mesenchymal phenotype of cancer cells that promotes invasive growth. Reduction in NMI levels has a feed-forward impact on miR-29 levels.
N-Myc interactor; EMT; Breast cancer; miR-29
Limited evidence in the US 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 study’s purpose was to describe the health status of rural vs urban residence among patients with COPD and to examine factors associated with differences between these 2 locations.
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.
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.
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.
COPD; health disparities; health-related quality of life; rural; utilization of health services
MicroRNAs (miRNAs) have potential prognostic value for colorectal cancers (CRCs); however, their value based on patient race/ethnicity and pathologic stage has not been determined. The goal was to ascertain the prognostic value of 5 miRNAs with increased expression in CRCs of African American (Black) and non-Hispanic Caucasian (White) patients.
TaqMan® qRT-PCR was used to quantify expression of miR-20a, miR-21, miR-106a, miR-181b, and miR-203 in paired normal and tumor CRC archival tissues collected from 106 Black and 239 White patients. The results were correlated with overall survival based on patient race/ethnicity and pathologic stage. Since decisions regarding adjuvant therapy are important for Stage III CRCs, and since miR-181b appeared to have prognostic value only for Stage III Black patients, we assessed its prognostic value in a separate cohort of Stage III CRCs of Blacks.
All 5 miRNAs had higher expression in CRCs (>1.0-fold) than in corresponding normal tissues. High expression of miR-203 was associated with poor survival of Whites with Stage IV CRCs (HR=3.00, 95% CI=1.29–7.53), but in Blacks it was an indicator of poor survival of patients with Stage I and II CRCs (HR=5.63, 95% CI=1.03–30.64). Increased miR-21 expression correlated with poor prognosis for White Stage IV patients (HR=2.50, 95% CI=1.07–5.83). In both test and validation cohorts, high miR-181b expression correlated with poor survival of only Black patients with Stage III CRCs (HR=1.94, 95% CI=1.03–3.67).
These preliminary findings suggest that the prognostic value of miRNAs in CRCs varies with patient race/ethnicity and stage of disease.
Race; miRNAs; prognosis; stage; colorectal cancer
Treatment of COPD requires multiple pharmacological and non-pharmacological intervention strategies. One target is physical inactivity because it leads to disability and contributes to poor physical and mental health. Unfortunately, less than one percent of eligible patients have access to gold-standard pulmonary rehabilitation.
A single-site parallel group randomized trial was designed to determine if a self-management lifestyle physical activity intervention would improve physical functioning and dyspnea. During the first six weeks after enrollment patients receive COPD self-management education delivered by a health coach using a workbook and weekly telephone calls. Patients are then randomized to usual care or the physical activity intervention. The 20 week physical activity intervention is delivered by the health coach using a workbook supported by alternating one-on-one telephone counseling and computer assisted telephone calls. Theoretical foundations include social cognitive theory and the transtheoretical model.
Primary outcomes include change in Chronic Respiratory Questionnaire (CRQ) dyspnea domain and 6-minute walk distance measured at 6-, 12-, and 18-months after randomization. Secondary outcomes include other CRQ domains (fatigue, emotion, and mastery), SF-12, and health care utilization. Other measures include process outcomes and clinical characteristics.
This theory driven self-management lifestyle physical activity intervention is designed to reach patients unable to complete center-based pulmonary rehabilitation. Results will advance knowledge and methods for dissemination of a potentially cost-effective program for patients with COPD.
chronic obstructive pulmonary disease; self-management; physical activity; lifestyle; pulmonary rehabilitation; randomized trial
Chronic obstructive pulmonary disease (COPD) is an illness that affects patients on multiple levels, both physically and psychologically. While there is a growing body of evidence for the efficacy of self-management among patients with COPD, little evidence is available on the optimal content and methods for delivering self-management support.
The purpose of this study was to address gaps in the literature on self-management support by examining patients’ responses to questions about goals, needs, and expectations regarding self-management using qualitative methods in a broadly representative sample of patients with moderate to severe COPD. By focusing on patients’ perceptions of their needs, we hoped to guide development of cognitive-behavioural interventions for self-management support.
Patients ≥45 years of age with a physician diagnosis of COPD were recruited as part of a larger randomised controlled trial designed to determine the effectiveness of a lifestyle behavioural intervention to increase physical activity. In-depth interviews were conducted at baseline data collection using 10 standardised open-ended questions tailored to examine factors relevant to self-management support including concerns, fears, learning needs, barriers, facilitators, and goals. All interviews were audio recorded and analysed using qualitative methods. Responses were coded by three raters into thematic categories.
A sample of 47 interviews with patients of mean age 68.4 years, 53% male, 87% white were used in the analysis. The distribution of spirometric impairment based on percent predicted forced expiratory volume in 1 second (FEV1) was moderate (57.5%), severe (31.9%), and very severe (10.6%). In response to questions targeting needs and goals for care, three main themes (loss, fear, and desire for improved care) and seven associated sub-themes were identified. Because of breathlessness and fatigue as well as symptoms from conditions other than COPD, patients reported the loss of ability to participate in pleasurable and necessary activities of daily living and the desire to recover at least some of their functioning. They expressed problems with social isolation and uncertainty about their prognosis, as well as the hope to improve. In addition, fearful experiences associated with uncontrolled breathlessness and a wish for greater understanding and knowledge about treatment were major concerns.
These qualitative results suggest that the content of self-management support for patients with COPD should focus on addressing patients’ fears associated with the uncertainty, progression, and suffering of their disease, their expectations about overcoming or replacing losses, their needs for improved health literacy and their desire for improved care. These responses indicate areas where cognitive-behavioural intervention should focus in order to enhance patient self-efficacy, motivation, and behavioural change for improved self-management.
chronic disease; cognitive-behaviour; COPD; qualitative research; self-management
The adoption of health information technology has been recommended as a viable mechanism for improving quality of care and patient health outcomes. However, the capacity of health information technology (i.e., availability and use of multiple and advanced functionalities), particularly in federally qualified health centers (FQHCs) on improving quality of care is not well understood. We examined associations between health information technology (HIT) capacity at FQHCs and quality of care, measured by the receipt of discharge summary, frequency of patients receiving reminders/notifications for preventive care/follow-up care, and timely appointment for specialty care.
The analyses used 2009 data from the National Survey of Federally Qualified Health Centers. The study included 776 of the FQHCs that participated in the survey. We examined the extent of HIT use and tested the hypothesis that level of HIT capacity is associated with quality of care. Multivariable logistic regressions, reporting unadjusted and adjusted odds ratios, were used to examine whether ‘FQHCs’ HIT capacity’ is associated with the outcome measures.
The results showed a positive association between health information technology capacity and quality of care. FQHCs with higher HIT capacity were significantly more likely to have improved quality of care, measured by the receipt of discharge summaries (OR=1.43; CI=1.01, 2.40), the use of a patient notification system for preventive and follow-up care (OR=1.74; CI=1.23, 2.45), and timely appointment for specialty care (OR=1.77; CI=1.24, 2.53).
Our findings highlight the promise of HIT in improving quality of care, particularly for vulnerable populations who seek care at FQHCs. The results also show that FQHCs may not be maximizing the benefits of HIT. Efforts to implement HIT must include strategies that facilitate the implementation of comprehensive and advanced functionalities, as well as promote meaningful use of these systems. Further examination of the role of health information systems in clinical decision-making and improvements in patient outcomes are needed to better understand the benefits of HIT in improving overall quality of care.
Health information technology; Federally qualified health centers; Electronic medical records; Quality of care; Patient reminder/notification; Adoption of technology; Meaningful use; Care coordination
The purpose of this study was to investigate the association between Attention Deficit/Hyperactivity Disorder (ADHD) and various factors using a representative sample of US children in a comprehensive manner. This includes variables that have not been previously studied such as watching TV/playing video games, computer usage, family member’s smoking, and participation in sports.
This was a cross-sectional study of 68,634 children, 5–17 years old, from the National Survey of Children’s Health (NSCH, 2007–2008). We performed bivariate and multivariate logistic regression analyses with ADHD classification as the response variable and the following explanatory variables: sex, race, depression, anxiety, body mass index, healthcare coverage, family structure, socio-economic status, family members’ smoking status, education, computer usage, watching television (TV)/playing video games, participation in sports, and participation in clubs/organizations.
Approximately 10% of the sample was classified as having ADHD. We found depression, anxiety, healthcare coverage, and male sex of child to have increased odds of being diagnosed with ADHD. One of the salient features of this study was observing a significant association between ADHD and variables such as TV usage, participation in sports, two-parent family structure, and family members’ smoking status. Obesity was not found to be significantly associated with ADHD, contrary to some previous studies.
The current study uncovered several factors associated with ADHD at the national level, including some that have not been studied earlier in such a setting. However, we caution that due to the cross-sectional and observational nature of the data, a cause and effect relationship between ADHD and the associated factors can not be deduced from this study. Future research on ADHD should take into consideration these factors, preferably through a longitudinal study design.
National Survey of Children’s Health; Neurobehavioral disorder; Obesity; Depression; Medication; TV usage; Participation in sports; Smoking status
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.
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, 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.
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 are lower than non metropolitan counties, however in metropolitan counties the rates of hospitalization are 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.
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.
The objective of this study was to examine hospital discharge data on 5 tobacco-related diagnoses before and after implementation of a smoking ban in a small Texas city. We compared hospital discharge rates for 2 years before and 2 years after implementation of the ban in the intervention city with discharge rates during the same time in a similar city with no ban. The discharge rates for blacks and whites combined declined significantly after the ban in the intervention city for acute myocardial infarction (MI) (rate ratio [RR], 0.74; 95% confidence interval [CI], 0.65–0.85) and for stroke or cerebrovascular accident (RR, 0.71; 95% CI, 0.62–0.82); discharge rates in the intervention city also declined significantly for chronic obstructive pulmonary disease (RR, 0.64; 95% CI, 0.54–0.75) and asthma (RR, 0.69; 95% CI, 0.52–0.91) for whites only. Discharge rates for 4 of 5 diagnoses in the control city did not change. Although postban reduction in acute MI is well documented, this is one of the first studies to show a racial disparity in health benefits and a decline in tobacco-related diagnoses other than acute MI after implementation of a city-wide smoking ban.
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).
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.
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.
health centers; COPD; health disparities
The purpose of this study was to develop a novel pelvic model and determine the accuracy, inter- and intra-examiner reliability of anterior superior iliac spine (ASIS) positional asymmetry assessment from both sides of the model by osteopathic pre-doctoral fellows and osteopathic physicians and to evaluate the effect of training.
Five osteopathic pre-doctoral fellows and 5 osteopathic physicians assessed 13 settings of varied ASIS asymmetry of a novel pelvic model for superior/inferior positional asymmetry from both sides of the model in a random order. Assessment from the right and left sides of the model occurred on 2 separate days. Fellows were trained for a week and retested.
Average inter-examiner reliability was greatest from the left side of the model for physicians and right side for fellows (physicians k=0.46; fellows k=0.37 respectively) while intra-examiner reliability was greatest from the right in both groups (physicians k=0.49; fellows k=0.52). Following training of fellows, inter-examiner reliability remained highest from the right side of the model (right: k=0.48; left: k=0.36) while intra-examiner reliability was higher from the left side (right: k=0.53; left: k=0.59). Physicians and fellows before training were more accurate from the right side of the model (k=0.56 and k=0.52 respectively). Following training of fellows, accuracy increased from both sides of the model (right: k=0.59; left: k=0.53).
A novel, pelvic model was developed to allow assessment of accuracy and reliability of ASIS asymmetry assessment. Individually, physicians and fellows varied in accuracy and inter-/intra-examiner reliability. Further investigation is warranted to understand the clinical and educational application of these results.
Palpation; Models, Anatomic; Osteopathic Manipulative Treatment; Chiropractic
The mini mental state examination (MMSE) is a common tool for measuring cognitive decline in Alzhiemer’s Disease (AD) subjects. Subjects are usually observed for a specified period of time or until death to determine the trajectory of the decline which for the most part appears to be linear. However, it may be noted that the decline may not be modeled by a single linear model over a specified period of time. There may be a point called a change point where the rate or gradient of the decline may change depending on the length of time of observation. A Bayesian approach is used to model the trajectory and determine an appropriate posterior estimate of the change point as well as the predicted model of decline before and after the change point. Estimates of the appropriate parameters as well as their posterior credible regions or regions of interest are established. Coherent prior to posterior analysis using mainly non informative priors for the parameters of interest is provided. This approach is applied to an existing AD database.
Alzheimer’s Disease; Bayesian; Change Point; Mini Mental State; Trajectory
The health impacts of pulmonary impairment after tuberculosis (TB) treatment have not been included in assessments of TB burden. Therefore, previous global and national TB burden estimates do not reflect the full consequences of surviving TB. We assessed the burden of TB including pulmonary impairment after tuberculosis in Tarrant County, Texas using Disability-adjusted Life Years (DALYs).
TB burden was calculated for all culture-confirmed TB patients treated at Tarrant County Public Health between January 2005 and December 2006 using identical methods and life tables as the Global Burden of Disease Study. Years of life-lost were calculated as the difference between life expectancy using standardized life tables and age-at-death from TB. Years lived-with-disability were calculated from age and gender-specific TB disease incidence using published disability weights. Non-fatal health impacts of TB were divided into years lived-with-disability-acute and years lived-with-disability-chronic. Years lived-with-disability-acute was defined as TB burden resulting from illness prior to completion of treatment including the burden from treatment-related side effects. Years lived-with-disability-chronic was defined as TB burden from disability resulting from pulmonary impairment after tuberculosis.
There were 224 TB cases in the time period, of these 177 were culture confirmed. These 177 subjects lost a total of 1189 DALYs. Of these 1189 DALYs 23% were from years of life-lost, 2% were from years lived-with-disability-acute and 75% were from years lived-with-disability-chronic.
Our findings demonstrate that the disease burden from TB is greater than previously estimated. Pulmonary impairment after tuberculosis was responsible for the majority of the burden. These data demonstrate that successful TB control efforts may reduce the health burden more than previously recognized.
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).
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.
The results of our study have shown that RLIP76 plays a central role in radiation resistance.
RLIP76; Ralbp1; Radiation-resistance; Embryonic fibroblasts
The purpose of this study is to identify factors affecting CSHCN's receiving needed specialty care among different socioeconomic levels. Previous literature has shown that Socioeconomic Status (SES) is a significant factor in CHSHCN receiving access to healthcare. Other literature has shown that factors of insurance, family size, race/ethnicity and sex also have effects on these children's receipt of care. However, this literature does not address whether other factors such as maternal education, geographic location, age, insurance type, severity of condition, or race/ethnicity have different effects on receiving needed specialty care for children in each SES level.
Data were obtained from the National Survey of Children with Special Health Care Needs, 2000–2002. The study analyzed the survey which studies whether CHSCN who needed specialty care received it. The analysis included demographic characteristics, geographical location of household, severity of condition, and social factors. Multiple logistic regression models were constructed for SES levels defined by federal poverty level: < 199%; 200–299%; ≥ 300%.
For the poorest children (,199% FPL) being uninsured had a strong negative effect on receiving all needed specialty care. Being Hispanic was a protective factor. Having more than one adult in the household had a positive impact on receipt of needed specialty care but a larger number of children in the family had a negative impact. For the middle income group of children (200–299% of FPL severity of condition had a strong negative association with receipt of needed specialty care.
Children in highest income group (> 300% FPL) were positively impacted by living in the Midwest and were negatively impacted by the mother having only some college compared to a four-year degree.
Factors affecting CSHCN receiving all needed specialty care differed among socioeconomic groups. These differences should be addressed in policy and practice. Future research should explore the CSHCN population by income groups to better serve this population
The purpose of this study was to determine the prevalence of high blood pressure (HBP) and associated risk factors in school children 8 to 13 years of age.
Elementary school children (n = 1,066) were examined. Associations between HBP, body mass index (BMI), gender, ethnicity, and acanthosis nigricans (AN) were investigated using a school based cross-sectional study. Blood pressure was measured and the 95th percentile was used to determine HBP. Comparisons between children with and without HBP were utilized. The crude and multiple logistic regression adjusted odds ratios were used as measures of association.
Females, Hispanics, overweight children, and children with AN had an increased likelihood of HBP. Overweight children (BMI ≥ 85th percentile) and those with AN were at least twice as likely to present with HBP after controlling for confounding factors.
Twenty one percent of school children had HBP, especially the prevalence was higher among the overweight and Hispanic group. The association identified here can be used as independent markers for increased likelihood of HBP in children.