Barriers and facilitators to nurses' acceptance of and implications for injury rates of an IV catheter safety device

This study has the purpose of determining the barriers and facilitators to nurses' acceptance of the Johnson and Johnson Protectiv®* Plus IV catheter safety needle device and implications for needlestick injuries at St. Luke's Episcopal Hospital, Houston, Texas. A one-time cross-sectional survey of 620 responding nurses was conducted by this researcher during December, 2000. The study objectives were to: (1) describe the perceived (a) organizational and individual barriers and facilitators and (b) acceptance of implementation of the IV catheter device; (2) examine the relative importance of these predictors; (3) describe (a) perceived changes in needlestick injuries after implementation of the device; (b) the reported incidence of injuries; and (c) the extent of underreporting by nurses; and (4) examine the relative importance of (a) the preceding predictors and (b) acceptance of the device in predicting perceived changes in needlestick injuries. Safety climate and training were evaluated as organizational factors. Individual factors evaluated were experience with the device, including time using it and frequency of use, and background information, including nursing unit, and length of time as a nurse in this hospital and in total nursing career. The conceptual framework was based upon the safety climate model. Descriptive statistics and multiple and logistic regression were utilized to address the study objectives. ^ The findings showed widespread acceptance of the device and a strong perception that it reduced the number of needlesticks. Acceptance was notably predicted by adequate training, appropriate time between training and device use, solid safety climate, and short length of service, in that order. A barrier to acceptance was nurses' longtime of use of previous needle technologies. Over four-fifths of nurses were compliant in always using the device. Compliance had two facilitators: length of time using device and, to a lesser extent, safety climate. Rates of compliance tended to be lower among nurses in units in which the device was frequently used. ^ High quality training and an atmosphere of caring about nurse safety stand out as primary facilitators that other institutions would need to adopt in order to achieve maximum success in implementing safety programs involving utilization of new safety devices. ^

Tracking of plasma lipids and lipoproteins, within-person and year-to-year variability in plasma cholesterol levels among participants from age 8 to 18 in Project HeartBeat!

Coronary heart disease remains the leading cause of death in the United States and increased blood cholesterol level has been found to be a major risk factor with roots in childhood. Tracking of cholesterol, i.e., the tendency to maintain a particular cholesterol level relative to the rest of the population, and variability in blood lipid levels with increase in age have implications for cholesterol screening and assessment of lipid levels in children for possible prevention of further rise to prevent adulthood heart disease. In this study the pattern of change in plasma lipids, over time, and their tracking were investigated. Also, within-person variance and retest reliability defined as the square root of within-person variance for plasma total cholesterol, HDL-cholesterol, LDL-cholesterol, and triglycerides and their relation to age, sex and body mass index among participants from age 8 to 18 years were investigated. ^ In Project HeartBeat!, 678 healthy children aged 8, 11 and 14 years at baseline were enrolled and examined at 4-monthly intervals for up to 4 years. We examined the relationship between repeated observations by Pearson's correlations. Age- and sex-specific quintiles were calculated and the probability of participants to remain in the uppermost quintile of their respective distribution was evaluated with life table methods. Plasma total cholesterol, HDL-C and LDL-C at baseline were strongly and significantly correlated with measurements at subsequent visits across the sex and age groups. Plasma triglyceride at baseline was also significantly correlated with subsequent measurements but less strongly than was the case for other plasma lipids. The probability to remain in the upper quintile was also high (60 to 70%) for plasma total cholesterol, HDL-C and LDL-C. ^ We used a mixed longitudinal, or synthetic cohort design with continuous observations from age 8 to 18 years to estimate within person variance of plasma total cholesterol, HDL-C, LDL-C and triglycerides. A total of 5809 measurements were available for both cholesterol and triglycerides. A multilevel linear model was used. Within-person variance among repeated measures over up to four years of follow-up was estimated for total cholesterol, HDL-C, LDL-C and triglycerides separately. The relationship of within-person and inter-individual variance with age, sex, and body mass index was evaluated. Likelihood ratio tests were conducted by calculating the deviation of −2log (likelihood) within the basic model and alternative models. The square root of within-person variance provided the retest reliability (within person standard deviation) for plasma total cholesterol, HDL-C, LDL-C and triglycerides. We found 13.6 percent retest reliability for plasma cholesterol, 6.1 percent for HDL-cholesterol, 11.9 percent for LDL-cholesterol and 32.4 percent for triglycerides. Retest reliability of plasma lipids was significantly related with age and body mass index. It increased with increase in body mass index and age. These findings have implications for screening guidelines, as participants in the uppermost quintile tended to maintain their status in each of the age groups during a four-year follow-up. The magnitude of within-person variability of plasma lipids influences the ability to classify children into risk categories recommended by the National Cholesterol Education Program. ^

Varying Injurer Costs of Care, Negligence, and Self-Selection

Standard economic models of negligence set a single standard of care to which all injurers must conform. When injurers differ in their costs of care, this leads to distortions in individual care choices. This paper derives the characteristics of a negligence rule that induces optimal care by all injurers by means of self-selection. The principal features of the rule are (1) the due standard is set at the optimal care of the lowest cost injurer, and (2) liability increases gradually rather than abruptly as care falls below this standard. The results are consistent with the gradation in liability under certain causation rules and under comparative negligence.

Survey of VFC provider knowledge of catch-up regimens and contraindications to vaccination in Houston, Texas

In 2004, Houston had one of the lowest childhood immunization levels among major metropolitan cities in the United States at 65% for the 4:3:1:3:3 vaccination series. Delays in the receipt of scheduled vaccinations may be related to missed opportunities due to health care provider lack of knowledge about catch-up regimens and contraindications for pediatric vaccination. The objectives of this study are to identify, measure, and report on VFC provider-practice characteristics, knowledge of catch-up regimens and contraindications, and use of Reminder recall (R/R) and moved or gone elsewhere (MOGE) practices among providers with high (>80%) and low (<70%) immunization coverage among 19-35 month old children. The sampling frame consists of 187 Vaccines for Children (VFC) providers with 2004 clinic assessment software application (CASA) scores. Data were collected by personal interview with each participating practice provider. Only ten VFC providers were successful at maximizing vaccinations for every vignette and no provider administered the maximum possible number of vaccinations at visit 2 for all six vignettes. Both coverage groups administered polio conjugate vaccine (PCV), haemophilus influenza type b (Hib), and diphtheria, tetanus and acellular pertussis (DTaP) most frequently and omitted most frequently varicella zoster vaccine (VZV) and measles, mumps, and rubella (MMR) vaccine. ^

Modifier genes and susceptibility to colorectal cancer in individuals with Lynch syndrome

Lynch syndrome, is caused by inherited germ-line mutations in the DNA mismatch repair genes resulting in cancers at an early age, predominantly colorectal (CRC) and endometrial cancers. Though the median age at onset for CRC is about 45 years, disease penetrance varies suggesting that cancer susceptibility may be modified by environmental or other low-penetrance genes. Genetic variation due to polymorphisms in genes encoding metabolic enzymes can influence carcinogenesis by alterations in the expression and activity level of the enzymes. Variation in MTHFR, an important folate metabolizing enzyme can affect DNA methylation and DNA synthesis and variation in xenobiotic-metabolizing enzymes can affect the metabolism and clearance of carcinogens, thus modifying cancer risk. ^ This study examined a retrospective cohort of 257 individuals with Lynch syndrome, for polymorphisms in genes encoding xenobiotic-metabolizing enzymes-- CYP1A1 (I462V and MspI), EPHX1 (H139R and Y113H), GSTP1 (I105V and A114V), GSTM1 and GSTT1 (deletions) and folate metabolizing enzyme--MTHFR (C677T and A1298C). In addition, a series of 786 cases of sporadic CRC were genotyped for CYP1A1 I462V and EPHX1 Y113H to assess gene-gene interaction and gene-environment interaction with smoking in a case-only analysis. ^ Prominent findings of this study were that the presence of an MTHFR C677T variant allele was associated with a 4 year later age at onset for CRC on average and a reduced age-associated risk for developing CRC (Hazard ratio: 0.55; 95% confidence interval: 0.36–0.85) compared to the absence of any variant allele in individuals with Lynch syndrome. Similarly, Lynch syndrome individuals heterozygous for CYP1A1 I462V A>G polymorphism developed CRC an average of 4 years earlier and were at a 78% increased age-associated risk (Hazard ratio for AG relative to AA: 1.78; 95% confidence interval: 1.16-2.74) than those with the homozygous wild-type genotype. Therefore these two polymorphisms may be additional susceptibility factors for CRC in Lynch syndrome. In the case-only analysis, evidence of gene-gene interaction was seen between CYP1A1 I462V and EPHX1 Y113H and between EPHX1 Y113H and smoking suggesting that genetic and environmental factors may interact to increase sporadic CRC risk. Implications of these findings are the ability to identify subsets of high-risk individuals for targeted prevention and intervention. ^

Disparities in medical expenditure and utilization among hypertensive men and women in the U.S.: Cross-section and lifetime analysis

Objectives. To investigate procedural gender equity by assessing predisposing, enabling and need predictors of gender differences in annual medical expenditures and utilization among hypertensive individuals in the U.S. Also, to estimate and compare lifetime medical expenditures among hypertensive men and women in the U.S. ^ Data source. 2001-2004 the Medical Expenditure Panel Survey (MEPS);1986-2000 National Health Interview Survey (NHIS) and National Health Interview Survey linked to mortality in the National Death Index through 2002 (2002 NHIS-NDI). ^ Study design. We estimated total medical expenditure using four equations regression model, specific medical expenditures using two equations regression model and utilization using negative binomial regression model. Procedural equity was assessed by applying the Aday et al. theoretical framework. Expenditures were estimated in 2004 dollars. We estimated hypertension-attributable medical expenditure and utilization among men and women. ^ To estimate lifetime expenditures from ages 20 to 85+, we estimated medical expenditures with cross-sectional data and survival with prospective data. The four equations regression model were used to estimate average annual medical expenditures defined as sum of inpatient stay, emergency room visits, outpatient visits, office based visits, and prescription drugs expenditures. Life tables were used to estimate the distribution of life time medical expenditures for hypertensive men and women at different age and factors such as disease incidence, medical technology and health care cost were assumed to be fixed. Both total and hypertension attributable expenditures among men and women were estimated. ^ Data collection. We used the 2001-2004 MEPS household component and medical condition files; the NHIS person and condition files from 1986-1996 and 1997-2000 sample adult files were used; and the 1986-2000 NHIS that were linked to mortality in the 2002 NHIS-NDI. ^ Principal findings. Hypertensive men had significantly less utilization for most measures after controlling predisposing, enabling and need factors than hypertensive women. Similarly, hypertensive men had less prescription drug (-9.3%), office based (-7.2%) and total medical (-4.5%) expenditures than hypertensive women. However, men had more hypertension-attributable medical expenditures and utilization than women. ^ Expected total lifetime expenditure for average life table individuals at age 20, was $188,300 for hypertensive men and $254,910 for hypertensive women. But the lifetime expenditure that could be attributed to hypertension was $88,033 for men and $40,960 for women. ^ Conclusion. Hypertensive women had more utilization and expenditure for most measures than hypertensive men, possibly indicating procedural inequity. However, relatively higher hypertension-attributable health care of men shows more utilization of resources to treat hypertension related diseases among men than women. Similar results were reported in lifetime analyses.^ Key words: gender, medical expenditures, utilization, hypertension-attributable, lifetime expenditure ^

Latino perceptions of and barriers to preventive healthcare maintenance in the southwest United States

Between the 1990 and 2000 Censuses, the Latino population accounted for 40% of the increase in the nation’s total population. The growing population of Latinos underscores the importance for understanding factors that influence whether and how Latinos take care of their health. According to the U.S. Department of Human Health Service’s Office of Minority Health (OMH), Latinos are at greater risk for health disparities (2003). Factors such as lack of health insurance and access to preventive care play a major role in limiting Latino use of primary health care (Institute of Medicine, 2005). Other significant barriers to preventive health care maintenance behaviors have been identified in current literature such as primary care physician interaction, self-perceived health status, and socio-cultural beliefs and traditions (Rojas-Guyler, King, Montieth and 2008; Meir, Medina, and Ory, 2007; Black, 1999). Despite these studies, there remains less information regarding interpersonal perceptions, environmental dynamics and individual and cultural attitudes relevant to utilization of healthcare (Rojas-Guyler, King, Montieth and 2008; Aguirre-Molina, Molina and Zambrana, 2001). Understanding the perceptions of Latinos and the barriers to health care could directly affect healthcare delivery. Improved healthcare utilization among Latinos could reduce the long term health consequences of many preventable and manageable diseases. The purpose of this study was to explore Latino perceptions of U.S. health care and desired changes by Latinos in the U.S. healthcare system. The study had several objectives, including to explore perceived barriers to healthcare utilization and the resulting effects on health among Latinos, to describe culturally influenced attitudes about health care and use of health care services among Latinos, and to make recommendations for reducing disparities by improving healthcare and its utilization. The current study utilized data that were collected as part of a larger study to examine multidimensional, cross-cultural issues relevant to interactions between healthcare consumers and providers. Qualitative methods were used to analyze four Spanish-language focus group transcripts to interpret cultural influences on perceptions and beliefs among Latinos. Direct coding of transcript content was carried out by two reviewers, who conducted independent reviews of each transcript. Team members developed and refined thematic categories, positive and negative cases, and example text segments for each theme and sub-theme. Incongruities of interpretations were resolved through extensive discussion. Study participants included 44 self-identified Latino adults (16 male, 28 female) between age 18 and 64 years. Thirty seven (84.1%) of the participants were immigrants. The study population comprised eight ethnic subgroups. While 31% of the participants reported being employed on a full-time basis, only 18.4% had medical insurance that was private or employee sponsored. Five major themes regarding the perceptions and healthcare utilization behaviors of Latinos were consistent across all focus groups and were identified during the analysis. These were: (1) healthcare utilization, experience, and access; (2) organizational and institutional systems; (3) communication and interpersonal interactions between healthcare provider, staff, and patient; (4) Latinos’ perception of their own health status; (5) cultural influences on healthcare utilization, which included an innovation termed culturally-bound locus of control. Healthcare utilization was directly influenced by healthcare experience, access, current health status, and cultural factors and indirectly influenced by organizational systems. There was a strong interdependence among the main themes. The ability to communicate and interact effectively with healthcare providers and navigate healthcare systems (organizational and institutional access) significantly influenced the participant’s health care experience, most often (indirectly) impacting utilization negatively. ^ Research such as this can help to identify those perceptions and attitudes held by Latinos concerning utilization or underutilization of healthcare systems. These data suggest that for healthcare utilization to improve among Latinos, healthcare systems must create more culturally competent environments by providing better language services at the organizational level and more culturally sensitive providers at the interpersonal level. Better understanding of the complex interactions between these impediments can aid intervention developments, and help health providers and researchers in determining appropriate, adequate, and effective measurers of care to better increase overall health of Latinos.^

Dietary intake patterns and relationships to polybrominated diphenyl ether (PBDE) and phthalate body burden

Polybrominated diphenyl ethers (PBDEs) and phthalates are chemicals of concern because of high levels measured in people and the environment as well as the demonstrated toxicity in animal studies and limited epidemiological studies. Exposure to these chemicals has been associated with a range of toxicological outcomes, including developmental effects, behavioral changes, endocrine disruption, effects on sexual health, and cancer. Previous research has shown that both of these classes of chemicals contaminate food in the United States and worldwide. However, how large a role diet plays in exposure to these chemicals is currently unknown. To address this question, an exploratory analysis of data collected as part of the 2003-04 National Health and Nutrition Examination Survey (NHANES) was conducted. Associations between dietary intake (assessed by 24-hour dietary recalls) for a range of food types (meat, poultry, fish, and dairy) and levels PBDEs and phthalate metabolites were analyzed using multiple linear regression modeling. Levels of individual PBDE congeners 28, 47, 99, 100 as well as total PBDEs were found to be significantly associated with the consumption of poultry. Metabolites of di-(2-ethylhexyl) phthalate (DEHP) were found to be associated with the consumption of poultry, as well as with an increased consumption of fat of animal origin. These results, combined with results from previous studies, suggest that diet is an important route of intake for both PBDEs and phthalates. Further research needs to be conducted to determine the sources of food contamination with these toxic chemicals as well as to describe the levels of contamination of US food in a large, representative sample.^

Understanding causes of hospitalization and access to care among newly diagnosed HIV patients in Houston, TX

More than a quarter of patients with HIV in the United States are diagnosed in hospital settings most often with advanced HIV related conditions.(1) There has been little research done on the causes of hospitalization when the patients are first diagnosed with HIV. The aim of this study was to determine if the patients are hospitalized due to an HIV related cause or due to some other co-morbidity. Reduced access to care could be one possible reason why patients are diagnosed late in the course of the disease. This study compared the access to care of patients diagnosed with HIV in hospital and outpatient setting. The data used for the study was a part of the ongoing study “Attitudes and Beliefs and Steps of HIV Care”. The participants in the study were newly diagnosed with HIV and recruited from both inpatient and outpatient settings. The primary and the secondary diagnoses from hospital discharge reports were extracted and a primary reason for hospitalization was ascertained. These were classified as HIV-related, other infectious causes, non–infectious causes, other systemic causes, and miscellaneous causes. Access to care was determined by a score based on responses to a set of questions derived from the HIV Cost and Services Utilization Study (HCSUS) on a 6 point scale. The mean score of the hospitalized patients and mean score of the patients diagnosed in an outpatient setting was compared. We used multiple linear regressions to compare mean differences in the two groups after adjusting for age, sex, race, household income educational level and health insurance at the time of diagnosis. There were 185 participants in the study, including 78 who were diagnosed in hospital settings and 107 who were diagnosed in outpatient settings. We found that HIV-related conditions were the leading cause of hospitalization, accounting for 60% of admissions, followed by non-infectious causes (20%) and then other infectious causes (17%). The inpatient diagnosed group did not have greater perceived access-to-care as compared to the outpatient group. Regression analysis demonstrated a statistically significant improvement in access-to-care with advancing education level (p=0.04) and with better health insurance (p=0.004). HIV-related causes account for many hospitalizations when patients are first diagnosed with HIV. Many of these HIV-related hospitalizations could have been prevented if patients were diagnosed early and linked to medical care. Programs to increase HIV awareness need to be an integral part of activities aimed at control of spread of HIV in the community. Routine testing for HIV infection to promote early HIV diagnosis can prevent significant morbidity and mortality.^

NHERF1 recruits the tumor suppressors PTEN and PHLPP to synergistically inhibit the PI-3K pathway

Glioblastoma multiforme is the most common form of brain cancer that presents patients with a poor prognosis that has remained unchanged over the past few decades. The tumor suppressor phosphatase PTEN antagonizes one of the major oncogenic pathways involved in the progression of glioblastoma, and is frequently deleted in this cancer type. Contrary to our expectations, we found that most glioblastoma cells expressing endogenous PTEN also harbor basal PI-3K/AKT activation mainly attributable to impaired PTEN membrane localization. This alteration correlated with a shift of the adaptor protein NHERF1, which contributes to PTEN membrane recruitment in normal cells, from the membrane to the cytoplasm. In cells expressing membrane-localized NHERF1, only simultaneous PTEN and NHERF1 depletion achieved AKT activation, suggesting the involvement of additional PI-3K/AKT suppressor regulated by NHERF1. We identified these novel interactors of NHERF1 as the PHLPP1 and PHLPP2 phosphatases. ^ NHERF1 directly interacted and recruited both PHLPP proteins to the membrane and, through both NHERF1 PDZ domains, assembled ternary complexes consisting of PTEN-NHERF1-PHLPP. Only simultaneous depletion of PTEN and PHLPP1 significantly activated AKT and increased proliferation in cells with membrane-localized NHERF1. Analysis of glioblastoma human tumors revealed frequent loss of membrane-localized NHERF1. On the other hand, targeting of NHERF1 to the membrane achieved suppression of AKT and cell proliferation. Our findings reveal a novel mechanism for PI-3K/AKT regulation by the synergistic cooperation between two important tumor suppressors, PTEN and PHLPP, via the scaffold protein NHERF1. ^

Use of light intensity, temperature, and humidity to verify exposure location

Research studies on the association between exposures to air contaminants and disease frequently use worn dosimeters to measure the concentration of the contaminant of interest. But investigation of exposure determinants requires additional knowledge beyond concentration, i.e., knowledge about personal activity such as whether the exposure occurred in a building or outdoors. Current studies frequently depend upon manual activity logging to record location. This study's purpose was to evaluate the use of a worn data logger recording three environmental parameters—temperature, humidity, and light intensity—as well as time of day, to determine indoor or outdoor location, with an ultimate aim of eliminating the need to manually log location or at least providing a method to verify such logs. For this study, data collection was limited to a single geographical area (Houston, Texas metropolitan area) during a single season (winter) using a HOBO H8 four-channel data logger. Data for development of a Location Model were collected using the logger for deliberate sampling of programmed activities in outdoor, building, and vehicle locations at various times of day. The Model was developed by analyzing the distributions of environmental parameters by location and time to establish a prioritized set of cut points for assessing locations. The final Model consisted of four "processors" that varied these priorities and cut points. Data to evaluate the Model were collected by wearing the logger during "typical days" while maintaining a location log. The Model was tested by feeding the typical day data into each processor and generating assessed locations for each record. These assessed locations were then compared with true locations recorded in the manual log to determine accurate versus erroneous assessments. The utility of each processor was evaluated by calculating overall error rates across all times of day, and calculating individual error rates by time of day. Unfortunately, the error rates were large, such that there would be no benefit in using the Model. Another analysis in which assessed locations were classified as either indoor (including both building and vehicle) or outdoor yielded slightly lower error rates that still precluded any benefit of the Model's use.^

Physical activity levels and access to places to be physically active

The built environment is recognized as having an impact on health and physical activity. Ecological theories of physical activity suggest that enhancing access to places to be physically active may increase activity levels. Studies show that users of fitness facilities are more likely to be active than inactive and active people are more likely to report access to fitness facilities. The purpose of this study was to examine the ecologic relationship between density of fitness facilities and self-reported levels of physical activity in adults in selected Metropolitan Statistical Areas (MSAs) in the United States.^ The 2007 MSA Business Patterns and the 2007 Behavioral Risk Factor Surveillance System (BRFSS) were used to gather fitness facility and physical activity data for 141 MSAs in the United States. Pearson correlations were performed between fitness facility density (number of facilities/100,000 people) and six summary measures of physical activity prevalence. Regional analysis was done using the nine U.S. Standard Regions for Temperature and Precipitation. ^ Direct correlations between fitness facility density and the percent of those physically active (r=0.27, 95% CI 0.11, 0.42, p=0.0012), those meeting moderate-intensity activity guidelines, (r=0.23, 95% CI 0.07, 0.38, p=0.006), and those meeting vigorous-intensity activity guidelines (r=0.30, 95% CI 0.14, 0.44, p=0.003) were found. An inverse correlation was found between fitness facility density and the percent of people physically inactive (r=-0.45, 95% CI -0.57, -0.31), p<0.0001). Regional analysis showed the same trends across most regions.^ Access to fitness facilities, defined here as fitness facility density, is related to physical activity levels. Results suggest the potential importance of the influence of the built environment on physical activity behaviors. Public health officials and city planners should consider the possible positive effect that increasing the number of fitness facilities in communities would have on activity levels.^

Concordance between medical records and personal interview in ascertaining breast cancer and diabetes status: Analysis of the south Texas women's health project

Accurate ascertainment of risk factors and disease status is vital in public health research for proper classification of research subjects. The two most common ways of obtaining this data is by self-report and review of medical records (MRs). South Texas Women’s Health Project was a case-control study looking at interrelationships between hormones, diet, and body size and breast cancer among Hispanic women 30-79 years of age. History of breast cancer, diabetes mellitus (DM) and use of DM medications was ascertained from a personal interview. At the time of interview, the subject identified her major health care providers and signed the medical records release form, which was sent to the designated providers. The MRs were reviewed to confirm information obtained from the interview.^ Aim of this study was to determine the sensitivity and specificity between MRs and personal interview in diagnosis of breast cancer, DM and DM treatment. We also wanted to assess how successful our low-cost approach was in obtaining pertinent MRs and what factors influenced the quality of MR or interview data. Study sample was 721 women with both self-report and MR data available by June 2007. Overall response rate for MR requests was 74.5%. MRs were 80.9% sensitive and 100% specific in confirming breast cancer status. Prevalence of DM was 22.7% from the interviews and 16% from MRs. MRs did not provide definite information about DM status of 53.6% subjects. Sensitivity and specificity of MRs for DM status was 88.9% and 90.4% respectively. Disagreement on DM status from the two sources was seen in 15.9% subjects. This discordance was more common among older subjects, those who were married and were predominantly Spanish speaking. Income and level of education did not have a statistically significantly association with this disagreement.^ Both self-report and MRs underestimate the prevalence of DM. Relying solely on MRs leads to greater misclassification than relying on self-report data. MRs have good to excellent specificity and thus serve as a good tool to confirm information obtained from self-report. Self-report and MRs should be used in a complementary manner for accurate assessment of DM and breast cancer status.^

Differential stress response and susceptibility to oxidative injury in alveolar macrophages from C57BL/6J and C3H/HeJ mice following oxidant exposure

Studies have demonstrated a variable response to ozone among individuals and animal species and strains. For instance, C57BL/6J mice have a greater inflammatory response to ozone exposure than C3H/HeJ mice. In these studies, I utilized these strain differences in an effort to derive a mechanistic explanation to the variable strain sensitivity to ozone exposure. Therefore, alveolar macrophages (AM) from C57BL/6J and C3H/HeJ mice were exposed in vitro to hydrogen peroxide ($\rm H\sb2O\sb2$), heat and acetyl ceramide or in vivo to ozone. Necrosis and DNA fragmentation in macrophages from the two murine strains were determined to assess cytotoxicity following these treatments. In addition, synthesis and expression of the stress proteins, stress protein 72 (SP72) and heme oxygenase (HO-1), were examined following treatments. The in vitro experiments were conducted to eliminate the possibility of in vivo confounders (i.e., differences in breathing rates in the two strains) and thus directly implicate some inherent difference between cells from the two murine strains. $\rm H\sb2O\sb2$ and heat caused greater cytotoxicity in AM from C57BL/6J than C3H/HeJ mice and DNA fragmentation was a particularly sensitive indicator of cell injury. Similarly, AM from C57BL/6J mice were more sensitive to ozone exposure than cells from C3H/HeJ mice. Exposure to either 1 or 0.4 ppm ozone caused greater cytotoxicity in macrophages from C57BL/6J mice compared to macrophages from C3H/HeJ mice. The increased sensitivity of AM to injury was associated with decreased synthesis and expression of stress proteins. AM from C57BL/6J mice synthesized and expressed significantly less stress proteins in response to heat and ozone than AM from C3H/HeJ mice. Heat treatment resulted in greater synthesis and expression of SP72. In addition, macrophages from C57BL/6J mice expressed lower amounts of HO-1 than macrophages from C3H/HeJ mice following 0.4 ppm ozone exposure. Therefore, AM from C57BL/6J mice are more susceptible to oxidative injury than AM from C3H/HeJ mice which might be due to differential expression of stress proteins in these cells. ^

Hispanic incorporation and access to health care in Houston and Harris County, Texas: Adopting an Hispanic perspective to the Aday and Andersen model

This study examines Hispanic levels of incorporation and access to health care. Applying the Aday and Andersen framework for the study of access, the study examined the relationship between two levels of Hispanic incorporation into U.S. society, i.e., mainstream versus ethnic, and potential and realized measures of access to health care. Data for the study were drawn from a 1992 telephone survey of 600 randomly selected Hispanics in Houston and Harris County.^ The hypotheses tested were: (1) Hispanics who are incorporated into mainstream society are more likely to have better potential and realized access to health care than those who are incorporated into ethnic-group enclaves regardless of their socioeconomic status (SES), health status and health needs, and (2) there is no interaction between the levels of incorporation (mainstream or ethnic) and SES, health status, and health needs in predicting potential and realized access.^ The data analysis supported Hypothesis One for the two measures of potential access. The results of bivariate and multiple logistic regression analyses indicated that for Hispanics in Houston and Harris County, being in the "mainstream" incorporation category increased their potential access to care, having "health insurance" and a "regular place of care". For the selected measure of realized access, having a "regular check-up", the analysis did not demonstrate statistically significant differences in having a regular check-up among Hispanics incorporated in the ethnic or mainstream incorporation categories.^ Hypothesis Two, that there is no interaction between the levels of incorporation and socioeconomic characteristics, health status, and health needs in predicting potential and realized access among Hispanics was supported by the data. The results of the logistic regression analysis showed that, after adjusting for socioeconomic status, health status, and health needs, the association between "level of incorporation" and the two measures of potential access ("health insurance" and having a "usual place of care") was not modified by the control variables nor by their interaction with level of incorporation. That is, the effect of incorporation on Hispanics' health insurance coverage, and having a usual place of care, was homogenous across Hispanics with different SES and health status.^ The main research implication of this dissertation is the employment of a theoretical framework for the assessment of cultural factors essential to research on migrating heterogeneous subpopulations. It also provided strategies to solve practical and methodological difficulties in the secondary analyses of data on these populations. ^