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Biomedical subjects

Robert L Phillips

Publications and source records attributed to Robert L Phillips.

At least 19 recordsLinked to original sources
PubMed2005

Skin biopsies for the measurement of clinical pharmacodynamic biomarkers.

The integration of biomarkers reporting on drug pharmacodynamics or on a disease state is becoming necessary in the cost-effective design of clinical trials. Transcriptional changes in skin measured using whole-genome arrays have been useful in assessing the disease state in dermatology. Not only are skin biopsies well-tolerated and easy to obtain, but they sample a system in which many complex signaling and developmental networks are active and in which a wide variety of drug targets may be expected to play a role, either directly or indirectly. Recent advances have led to the use of transcriptional profiling of skin for making pharmacodynamic measurements in clinical trials, even for non-dermatological conditions.

Animals↗
PubMed2005

Using the ecology model to describe the impact of asthma on patterns of health care.

BACKGROUND: Asthma changes both the volume and patterns of healthcare of affected people. Most studies of asthma health care utilization have been done in selected insured populations or in a single site such as the emergency department. Asthma is an ambulatory sensitive care condition making it important to understand the relationship between care in all sites across the health service spectrum. Asthma is also more common in people with fewer economic resources making it important to include people across all types of insurance and no insurance categories. The ecology of medical care model may provide a useful framework to describe the use of health services in people with asthma compared to those without asthma and identify subgroups with apparent gaps in care. METHODS: This is a case-control study using the 1999 U.S. Medical Expenditure Panel Survey. Cases are school-aged children (6 to 17 years) and young adults (18 to 44 years) with self-reported asthma. Controls are from the same age groups who have no self-reported asthma. Descriptive analyses and risk ratios are placed within the ecology of medical care model and used to describe and compare the healthcare contact of cases and controls across multiple settings. RESULTS: In 1999, the presence of asthma significantly increased the likelihood of an ambulatory care visit by 20 to 30% and more than doubled the likelihood of making one or more visits to the emergency department (ED). Yet, 18.8% of children and 14.5% of adults with asthma (over a million Americans) had no ambulatory care visits for asthma. About one in 20 to 35 people with asthma (5.2% of children and 3.6% of adults) were seen in the ED or hospital but had no prior or follow-up ambulatory care visits. These Americans were more likely to be uninsured, have no usual source of care and live in metropolitan areas. CONCLUSION: The ecology model confirmed that having asthma changes the likelihood and pattern of care for Americans. More importantly, the ecology model identified a subgroup with asthma who sought only emergent or hospital services.

Adult↗
PubMed2005

Regulation of gene expression by lithium and depletion of inositol in slices of adult rat cortex.

Lithium inhibits inositol monophosphatase at therapeutically effective concentrations, and it has been hypothesized that depletion of brain inositol levels is an important chemical alteration for lithium's therapeutic efficacy in bipolar disorder. We have employed adult rat cortical slices as a model to investigate the gene regulatory consequences of inositol depletion effected by lithium using cytidine diphosphoryl-diacylglycerol as a functionally relevant biochemical marker to define treatment conditions. Genes coding for the neuropeptide hormone pituitary adenylate cyclase activating polypeptide (PACAP) and the enzyme that processes PACAP's precursor to the mature form, peptidylglycine alpha-amidating monooxygenase, were upregulated by inositol depletion. Previous work has shown that PACAP can increase tyrosine hydroxylase (TH) activity and dopamine release, and we found that the gene for GTP cyclohydrolase, which effectively regulates TH through synthesis of tetrahydrobiopterin, was also upregulated by inositol depletion. We propose that modulation of brain PACAP signaling might represent a new opportunity in the treatment of bipolar disorder.

Animals↗
PubMed2005

Changes in age-adjusted mortality rates and disparities for rural physician shortage areas staffed by the National Health Service Corps: 1984-1998.

OBJECTIVE: This study assesses whether the National Health Service Corps's legislated goals to see health improve and health disparities lessen are being met in rural health professional shortage areas for a key population health indicator: age-adjusted mortality. METHODS: In a descriptive study using a pre-post design with comparison groups, the authors calculated age-adjusted mortality rates at baseline (1981-1983) and follow-up (1996-1998) for the populations of 448 rural whole-county health professional shortage areas arrayed into 3 groups based on the number of study years they were staffed by National Health Service Corps physicians, physician assistants, and nurse practitioners (terms of 1 to 7, 8 to 11, and 12 to 15 years). The authors compared changes over time in age-adjusted mortality rates in the 3 county groups that had National Health Service Corps staffing with rate changes in 172 whole-county rural health professional shortage areas and 772 non-health professional shortage area rural counties that had no National Health Service Corps. RESULTS: At baseline age-adjusted mortality was higher in all 4 health professional shortage area county groups than in the non-health professional shortage area county group. Age-adjusted mortality rates improved with time in all groups, including health professional shortage area counties both with and without National Health Service Corps support, and non-health professional shortage area counties. Essentially, baseline differences in age-adjusted mortality rates between health professional shortage areas and non-health professional shortage area counties did not diminish with time, whether or not there was National Health Service Corps support. CONCLUSIONS: From the early 1980s through the mid-1990s, the National Health Service Corps's goal to see health improve in rural health professional shortage areas was met, but its goal to diminish geographical health disparities was not. Because age-adjusted mortality rates improved in all county groups, the authors conclude that improvement was likely due to a variety of factors, including decreasing poverty and unemployment rates and increasing primary care physician-to-population ratios, to which the National Health Service Corps may have contributed.

Adult↗
PubMed2005

Identification of biomarkers for tumor endothelial cell proliferation through gene expression profiling.

Extensive efforts are under way to identify antiangiogenic therapies for the treatment of human cancers. Many proposed therapeutics target vascular endothelial growth factor (VEGF) or the kinase insert domain receptor (KDR/VEGF receptor-2/FLK-1), the mitogenic VEGF receptor tyrosine kinase expressed by endothelial cells. Inhibition of KDR catalytic activity blocks tumor neoangiogenesis, reduces vascular permeability, and, in animal models, inhibits tumor growth and metastasis. Using a gene expression profiling strategy in rat tumor models, we identified a set of six genes that are selectively overexpressed in tumor endothelial cells relative to tumor cells and whose pattern of expression correlates with the rate of tumor endothelial cell proliferation. In addition to being potential targets for antiangiogenesis tumor therapy, the expression patterns of these genes or their protein products may aid the development of pharmacodynamic assays for small molecule inhibitors of the KDR kinase in human tumors.

Angiogenesis Inhibitors↗
PubMed2004

A microarray platform comparison for neuroscience applications.

To address the need for high sensitivity in gene expression profiling of small neural tissue samples ( approximately 100 ng total RNA), we compared a novel RT-PCR-IVT protocol using fluor-reverse pairs on inkjet oligonucleotide microarrays and an RT-IVT protocol using 33P labeling on nylon cDNA arrays. The comparison protocol was designed to evaluate these systems for sensitivity, specificity, reproducibility, and linearity. We developed parameters, thresholds, and testing conditions that could be used to differentiate various systems that spanned detection chemistry and instrumentation; probe number and selection criteria; and sample processing protocols. We concluded that the inkjet system had better performance in sensitivity, specificity, and reproducibility than the nylon system, and similar performance in linearity. Between these two platforms, the data indicates that the inkjet system would perform better for the transcriptional profiling of 100 ng total RNA samples for neuroscience studies.

Animals↗
PubMed2004

Variation in participation in health care settings associated with race and ethnicity.

OBJECTIVE: To use the ecology model of health care to contrast participation of black, non-Hispanics (blacks); white, non-Hispanics (whites); and Hispanics of any race (Hispanics) in 5 health care settings and determine whether disparities between those individuals exist among places where they receive care. DESIGN: 1996 Medical Expenditure Panel Survey data were used to estimate the number of black, white, and Hispanic people per 1,000 receiving health care in each setting. SETTING: Physicians' offices, outpatient clinics, hospital emergency departments, hospitals, and people's homes. MAIN MEASUREMENT: Number of people per 1,000 per month who had at least one contact in a health care setting. RESULTS: Fewer blacks and Hispanics than whites received care in physicians' offices (154 vs 155 vs 244 per 1,000 per month, respectively) and outpatient clinics (15 vs 12 vs 24 per 1,000 per month, respectively). There were no significant differences in proportions hospitalized or receiving care in emergency departments. Fewer Hispanics than blacks or whites received home health care services (7 vs 14 vs 14 per 1,000 per month, respectively). After controlling for 7 variables, blacks and Hispanics were less likely than whites to receive care in physicians' offices (odds ratio [OR], 0.65, 95% confidence interval [CI], 0.60 to 0.69 for blacks and OR, 0.79, 95% CI, 0.73 to 0.85 for Hispanics), outpatient clinics (OR, 0.73, 95% CI, 0.60 to 0.90 for blacks and OR, 0.71, 95% CI, 0.58 to 0.88 for Hispanics), and hospital emergency departments (OR, 0.80, 95% CI, 0.69 to 0.94 for blacks and OR, 0.80, 95% CI, 0.68 to 0.93 for Hispanics) in a typical month. The groups did not differ in the likelihood of receiving care in the hospital or at home. CONCLUSIONS: Fewer blacks and Hispanics than whites received health care in physicians' offices, outpatient clinics, and emergency departments in contrast to hospitals and home care. Research and programs aimed at reducing disparities in receipt of care specifically in the outpatient setting may have an important role in the quest to reduce racial and ethnic disparities in health.

Black or African American↗
PubMed2004

Geographic retrofitting: a method of community definition in community-oriented primary care practices.

Community definition is an important aspect of community health work in general and community-oriented primary care (COPC) in particular. Yet, community definitions are often nonspecific, relying on geopolitical boundaries or local presumptions about patient populations. Such definitions are an impediment to the precise application of sociodemographic or health status data to community health problems or to targeted community organizing. This paper describes a technique called "geographic retrofitting" that has proved useful in establishing a rigorous definition of a practice's community based on current patterns of health care by the community. It also demonstrates how this approach, used in conjunction with geographic information systems software, facilitates more-powerful capabilities in community characterization and intervention.

Catchment Area, Health↗
PubMed2004

Modifiable determinants of healthcare utilization within the African-American population.

BACKGROUND: Significant health disparities directly affect the African-American population. Most previous studies of disparities in access to and utilization of healthcare have focused on black-white differences rather than focusing on "within-group" analysis of African Americans. OBJECTIVE: To tease out the differential effects of modifiable risk factors (such as health insurance, usual source of care, and poverty) from personal characteristics (age, gender, rural residence) on healthcare utilization within the African-American population. METHODS: Secondary data analysis of 3462 records from African-American respondents to the 1999 Medical Expenditure Panel Survey (MEPS) Household File, a nationally representative survey of the civilian, noninstitutionalized U.S. population in 1999. RESULTS: We found significant variation in the number of office visits, outpatient clinic visits, hospital discharges, days hospitalized, and fills of prescribed medication among 3462 African-American respondents who represent a U.S. population of 36,538,639 persons. Personal nonmodifiable characteristics such as age and gender were significantly related to healthcare utilization. Poverty and rural residence were also significantly correlated, but the strongest modifiable predictors of healthcare utilization for Afrcan-American persons in 1999 were whether or not individuals had health insurance and/or a usual source of care. Emergency department visits were the only form of care that showed remarkably little variation based on these modifiable risk factors. CONCLUSIONS: The three modifiable factors of poverty, uninsurance, and having a primary care medical home have a dramatic effect on patterns of care for African-American patients and could be independently targeted for intervention.

Adolescent↗
PubMed2003

Oral vitamin D3 decreases fracture risk in the elderly.

Vitamin D3 (or its physiologic equivalent, ergocalciferol), administered at a dose of 100,000 IU every 4 months for 5 years, is effective for primary prevention of fractures in the active elderly aged 65 to 85 years. This treatment regimen has no effect on cardiovascular, cancer, or all-cause mortality. Despite a seemingly large dose averaging 800 IU per day, this regimen is a safe, cheap (<$2 per year), and effective therapy for primary prevention of fractures.

Comment↗
PubMed2002

Does career dissatisfaction affect the ability of family physicians to deliver high-quality patient care?

OBJECTIVES: A usual source of care is associated with better health outcomes. Dissatisfaction among family physicians and general practitioners (FP/GPs) may compromise the accessibility of a usual source of care and the quality of services. We examined the association between FP/GP dissatisfaction and an inability to deliver high-quality care. STUDY DESIGN: We performed a secondary data analysis of the Community Tracking Study (CTS) Physician Survey (1996-1997). POPULATION: The study included a nationally representative sample of more than 12,000 nonfederal physicians practicing direct patient care in the United States. OUTCOMES MEASURED: We measured associations of career dissatisfaction with physicians&amprsquo perceptions of their ability to provide high-quality care as defined by 6 survey items. Multivariate analyses controlled for the effects of personal, professional, and practice characteristics. RESULTS: Among FP/GPs in 1996-1997, more than 17% were dissatisfied. Age was the most significant personal factor associated with dissatisfaction; 25.1% of those aged 55 to 64 years reported dissatisfaction compared with only 10.1% of those younger than 35 years. Other personal or professional characteristics significantly associated with FP/GP dissatisfaction included osteopathic training, graduation from a foreign medical school, full practice ownership, and an income of less than $100,000. Physicians dissatisfied with their careers were much more likely to report difficulties in caring for patients, strongly disagreeing (vs strongly agreeing, odds ratio [OR] 1.0) that they had enough clinical freedom (OR 7.89; 95% confidence interval [CI], 4.86-12.83); continuous patient relationships (OR 7.11; 95% CI, 4.90-10.33); no financial penalties for clinical decisions (OR 4.44; 95% CI, 3.13-6.31); adequate time with patients (OR 4.42; 95% CI, 2.84-6.87); ability to provide quality care (OR 4.26; 95% CI, 2.88-6.31); and sufficient communication with specialists (OR 3.57; CI, 2.20-5.80). CONCLUSIONS: An inability to care for patients is significantly associated with career dissatisfaction. This relationship has implications for the achievement of policy objectives related to access, having a usual source of care, and quality.

Adult↗