Resource allocation in public sector programmes: does the value of a life differ between governmental departments?

BACKGROUND

The value of a life is regularly monetised by government departments for informing resource allocation. Guidance documents indicate how economic evaluation should be conducted, often specifying precise values for different impacts. However, we find different values of life and health are used in analyses by departments within the same government despite commonality in desired outcomes. This creates potential inconsistencies in considering trade-offs within a broader public sector spending budget. We provide evidence to better inform the political process and to raise important issues in assessing the value of public expenditure across different sectors.

METHODS

Our document analysis identifies thresholds, explicitly or implicitly, as observed in government-related publications in the following public sectors: health, social care, transport, and environment. We include both demand-side and supply-side thresholds, understood as societies' and governments' willingness to pay for health gains. We look at key countries that introduced formal economic evaluation processes early on and have impacted other countries' policy development: Australia, Canada, Japan, New Zealand, the Netherlands, and the United Kingdom. We also present a framework to consider how governments allocate resources across different public services.

RESULTS

Our analysis supports that identifying and describing the Value of a Life from disparate public sector activities in a manner that facilitates comparison is theoretically meaningful. The optimal allocation of resources across sectors depends on the relative position of benefits across different attributes, weighted by the social value that society puts on them. The value of a Quality-Adjusted Life Year is generally used as a demand-side threshold by Departments of transport and environment. It exceeds those used in health, often by a large enough proportion to be a multiple thereof. Decisions made across departments are generally based on an unspecified rationing rule.

CONCLUSIONS

Comparing government expenditure across different public sector departments, in terms of the value of each department outcome, is not only possible but also desirable. It is essential for an optimal resource allocation to identify the relevant social attributes and to quantify the value of these attributes for each department.

Unmet Parenthood Goals, Health-Related Quality of Life and Apparent Irrationality: Understanding the Value of Treatments for Infertility

An increasing number of prospective parents are experiencing infertility along with associated negative impacts on mental health and life satisfaction that can extend across a network of individuals and family members. Assistive reproductive technologies (ART) can help prospective parents achieve their parenthood goals but, like any health technology, they must demonstrate acceptable 'value for money' to qualify for public funding. We argue that current approaches to understanding the value of ART, including quality-adjusted life-year (QALY) gains based on changes in health-related quality of life (HRQOL) and, more often, cost per live birth, are too narrow to capture the full impact of unmet parenthood goals and ART. We see a fundamental disconnect between measures of HRQOL and broader measures of wellbeing associated with met and unmet parenthood goals. We also suggest that simple concepts such as 'patient' and 'carer' are of limited applicability in the context of ART, where 'spillovers' extend across a wide network of individuals, and the person receiving treatment is often not the infertile individual. Consideration of individual and societal wellbeing beyond HRQOL is necessary to understand the full range of negative impacts associated with unmet parenthood goals and the corresponding positive impacts of successful ART. We suggest moving towards a wellbeing perspective on value to achieve a fuller understanding of value and promote cross-sector allocative efficiency.

Impact of patient-centered prescription medication labels on adherence in community pharmacy

BACKGROUND

Prescription medication labels are often constructed in a manner which hinders safe and appropriate use of medicines. The United States Pharmacopeia released voluntary standards to revise medication labels in an effort to support patients' understanding and improve medication use.

OBJECTIVE

To examine the impact of label changes on medication adherence before and after pharmacy implementation of the United States Pharmacopeia patient-centered prescription medication label standards.

METHODS

This study used a retrospective pre-post cohort design. Prescription fill claims data were obtained from a community health plan serving Medicaid patients for 1 independent community pharmacy organization across 8 retail pharmacy sites. We calculated medication possession ratios (MPR) and proportion of days covered (PDC) for medications used for contraception, asthma, hypertension, and depression from 15 months before to 13 months after implementation of the label changes.

RESULTS

Findings showed significant increases in mean MPR for asthma controller (increased by 0.111 [t = 0.290, P<0.0001]), antihypertensives (increased by 0.062 [t = 0.146, P < 0.0002]), and contraceptives medications (increased 0.133 [t = 0.209, P < 0.0001]) from preintervention to postintervention periods. Results also revealed increases in mean PDC for asthma controllers (increased by 0.193 [t = 0.267, P < 0.0001]), antihypertensives (increased by 0.067 [t = 0.175, P = 0.049]), and contraceptives (increased by 0.111 [t = 0.208, P < 0.0119]) from preintervention to postintervention periods.

CONCLUSION

We report an association between a change to more patient-centered prescription medication labels and increased medication adherence based on MPR and PDC among Medicaid recipients.

EQ-5D-Y Value Set for Germany

BACKGROUND

Demand is increasing for youth-specific preference-based health-related quality-of-life measures for inclusion in evaluations of healthcare interventions for children and adolescents. The EQ-5D-Youth (EQ-5D-Y) has the potential to become such a preference-based measure.

OBJECTIVE

This study applied the recently published EQ-5D-Y valuation protocol to develop a German EQ-5D-Y value set and explored the differences between values given to youth health by parents and non-parents.

METHODS

To elicit EQ-5D-Y health state preferences, a representative sample of 1030 adults of the general population completed a discrete choice experiment (DCE) online survey, and 215 adults participated in face-to-face interviews applying composite time trade-off (cTTO). Respondents were asked to consider a 10-year-old child living in the health states. DCE data were modelled using a mixed logit model. To derive the value set, DCE latent scale values were anchored onto adjusted mean cTTO values using a linear mapping approach.

RESULTS

Adult respondents considered pain/discomfort and feeling worried/sad/unhappy as the two most important dimensions in terms of youth health. Adjusted mean cTTO values ranged from - 0.350 for health state 33333 to 0.970 for health state 21111. The EQ-5D-Y value set showed a logical order for all parameter estimates, and predicted values ranged from - 0.283 to 1. Differences in preferences by parental status were mainly observed for cTTO results, where mean values were larger for parents than for non-parents.

CONCLUSIONS

Applying the valuation protocol, a German EQ-5D-Y value set with internally consistent coefficients was developed. This enables the instrument to be used in economic evaluations of paediatric healthcare interventions.

Considering Severity in Health Technology Assessment: Can We Do Better?

There is strong evidence that individuals and the public assign relatively greater value to health gains from relatively more severe health states. This preference is increasingly reflected in health technology assessment, with some consideration of severity incorporated by health technology assessment bodies in, among others, The Netherlands, England and Wales, Norway, Sweden, and the United States. If a societal "severity premium" is to be considered fairly and consistently, we argue that a more explicit and quantitative approach is needed. We highlight drawbacks of categorical approaches, especially discontinuities between severity categories that arguably violate concepts of vertical equity, and argue that a more continuous approach to understanding severity is needed. We also note challenges to more explicit approaches, including implications of a lower threshold for less severe conditions and the relative complexity of calculating a continuous severity adjustment.

Does Changing the Age of a Child to be Considered in 3-Level Version of EQ-5D-Y Discrete Choice Experiment-Based Valuation Studies Affect Health Preferences?

OBJECTIVES

There has been some debate about the choice of perspective and the age of the child considered when completing preference elicitation tasks in the 3-level version of EQ-5D-Y (EQ-5D-Y-3L) valuation protocol. This study aimed to clarify the impact on latent scale EQ-5D-Y-3L values of varying the age of the child experiencing the health state considered by respondents completing the discrete choice experiment (DCE) tasks of the protocol.

METHODS

We conducted an online DCE with a representative sample of 1000 adults in the United Kingdom and 1000 adults in the United States. Respondents selected the health state they prefer from a series of DCE paired EQ-5D-Y-3L health state comparisons using their own perspective and that of a hypothetical child from the following age groups: "5-7 years old," "8-10 years old," "11-13 years old," and "14-15 years old." Data analysis was conducted using separate multinomial logit models for each perspective and country. We also estimated combined models including data from each possible pair of perspectives and used interactions between EQ-5D-Y-3L levels and perspective to determine whether any differences were statistically significant.

RESULTS

No statistically significant differences in coefficients between perspectives were found in the United States. In the United Kingdom, there were differences between the own perspective and the 5 to 7 years old perspective (looking after myself level 3) and between the 5 to 7 years old perspective and the 8 to 10 years old perspective (usual activities level 3).

CONCLUSIONS

Our results suggest that there is minimal impact on latent scale values when using different ages of the hypothetical child in the current EQ-5D-Y-3L valuation protocol.

Accounting for Preference Heterogeneity in Discrete-Choice Experiments: An ISPOR Special Interest Group Report

OBJECTIVES

Discrete choice experiments (DCEs) are increasingly used to elicit preferences for health and healthcare. Although many applications assume preferences are homogenous, there is a growing portfolio of methods to understand both explained (because of observed factors) and unexplained (latent) heterogeneity. Nevertheless, the selection of analytical methods can be challenging and little guidance is available. This study aimed to determine the state of practice in accounting for preference heterogeneity in the analysis of health-related DCEs, including the views and experiences of health preference researchers and an overview of the tools that are commonly used to elicit preferences.

METHODS

An online survey was developed and distributed among health preference researchers and nonhealth method experts, and a systematic review of the DCE literature in health was undertaken to explore the analytical methods used and summarize trends.

RESULTS

Most respondents (n = 59 of 70, 84%) agreed that accounting for preference heterogeneity provides a richer understanding of the data. Nevertheless, there was disagreement on how to account for heterogeneity; most (n = 60, 85%) stated that more guidance was needed. Notably, the majority (n = 41, 58%) raised concern about the increasing complexity of analytical methods. Of the 342 studies included in the review, half (n = 175, 51%) used a mixed logit with continuous distributions for the parameters, and a third (n = 110, 32%) used a latent class model.

CONCLUSIONS

Although there is agreement about the importance of accounting for preference heterogeneity, there are noticeable disagreements and concerns about best practices, resulting in a clear need for further analytical guidance.

A European, prospective, observational study of enzalutamide in patients with metastatic castration-resistant prostate cancer: PREMISE

In randomized clinical trials, the androgen‐receptor inhibitor enzalutamide has demonstrated efficacy and safety in metastatic castration‐resistant prostate cancer (mCRPC). This study captured efficacy, safety and patient‐reported outcomes (PROs) of enzalutamide in mCRPC patients in a real‐world European setting. PREMISE (NCT0249574) was a European, long‐term, prospective, observational study in mCRPC patients prescribed enzalutamide as part of standard clinical practice. Patients were categorized based on prior docetaxel and/or abiraterone use. The primary endpoint was time to treatment failure (TTF), defined as time from enzalutamide initiation to permanent treatment discontinuation for any reason. Secondary endpoints included prostate‐specific antigen (PSA) response, time to PSA progression, time to disease progression and safety. PROs included EuroQol 5‐Dimension, 5‐Level questionnaire, Functional Assessment of Cancer Therapy—Prostate and Brief Pain Inventory—Short Form. Overall, 1732 men were enrolled. Median TTF with enzalutamide was 12.9 months in the chemotherapy‐ and abiraterone‐naïve cohort (Cohort 1) and 8.4 months in the postchemotherapy and abiraterone‐naïve cohort (Cohort 2). Clinical outcomes based on secondary endpoints also varied between cohorts. Cohorts 1 and 2 showed small improvements in health‐related quality of life and pain status. The proportions of patients reporting treatment‐emergent adverse events (TEAEs) were 51.0% and 62.2% in Cohorts 1 and 2, respectively; enzalutamide‐related TEAEs were similar in both cohorts. The most frequent TEAE across cohorts was fatigue. These data from unselected mCRPC patients in European, real‐world, clinical‐practice settings confirmed the benefits of enzalutamide previously shown in clinical trial outcomes, with safety results consistent with enzalutamide's known safety profile.

What's new?

In clinical trials, the androgen‐receptor inhibitor enzalutamide has demonstrated efficacy and safety in metastatic castration‐resistant prostate cancer (mCRPC). However, results in the real world may differ from those in controlled studies. This large, prospective study thus assessed unselected mCRPC patients with different prior treatment histories, who were then treated with enzalutamide. The results confirm and validate the benefits of enzalutamide in real‐world, clinical‐practice settings that were previously seen in clinical‐trial outcomes. These include improved health‐related quality of life (HRQoL).

Pharmacist Segments Identified from 2009, 2014, and 2019 National Pharmacist Workforce Surveys: Implications for Pharmacy Organizations and Personnel

Background/Objective: Findings from the 2009 and 2014 National Pharmacist Workforce Surveys showed that approximately 40% of U.S. pharmacists devoted their time primarily to medication providing, 40% contributed a significant portion of their time to patient care service provision, and the remaining 20% contributed most of their time to other health-system improvement activities. The objective of this study was to characterize the U.S. pharmacist workforce into segments based on the proportion of time they spend in medication providing and patient care services and compare changes in these segments between 2009, 2014, and 2019. Methods: Data from 2009, 2014, and 2019 National Pharmacist Workforce Surveys were analyzed. Responses from 1200 pharmacists in 2009, 1382 in 2014, and 4766 in 2019 were used for analysis. Respondents working in the pharmacy or pharmacy-related fields reported both their percent time devoted to medication providing and to patient care services. Medication providing included preparing, distributing, and administering medication products, including associated professional services. Patient care services were professional services designed for assessing and evaluating medication-related needs, monitoring and adjusting patient's treatments, and other services designed for patient care. For each year of data, pharmacist segments were identified using a two-step cluster analysis. Descriptive statistics were used for describing the characteristics of the segments. Results: For each year, five segments of pharmacists were identified. The proportions of pharmacists in each segment for the three surveys (2009, 2014, 2019) were: (1) medication providers (41%, 40%, 34%), (2) medication providers who also provide patient care (25%, 22%, 25%), (3) other activity pharmacists (16%, 18%, 14%), (4) patient care providers who also provide medication (12%, 13%, 15%), and (5) patient care providers (6%, 7%, 12%). In 2019, other activity pharmacists worked over 45 hours per week, on average, with 12 of these hours worked remotely. Patient care providers worked 41 hours per week, on average, with six of these hours worked remotely. Medication providers worked less than 40 hours per week, on average, with just one of these hours worked remotely. Regarding the number of patients with whom a respondent interacted on a typical day, medication providers reported 18 per day, patient care providers reported 11 per day, and other activity pharmacists reported 6 per day. In 2009, 8% of patient care providers worked in a setting that was not licensed as a pharmacy. In 2019, this grew to 17%. Implications/Conclusions: The 2019 findings showed that 34% of U.S. pharmacists devoted their time primarily to medication providing (compared to 40% in 2009 and 2014), 52% contributed a significant portion of their time to patient care service provision (compared to 40% in 2009 and 2014), and the remaining 14% contributed most of their time to other health-system improvement activities. Distinguishing characteristics of the segments suggested that recent growth in the pharmacist workforce has been in the patient care services, with more being provided through remote means in organizations that are not licensed as pharmacies. The findings have implications for pharmacist training, continuing education, labor monitoring, regulations, work systems, and process designs. These changes will create new roles and tasks for pharmacy organizations and personnel that will be needed to support emerging patient care services provided by pharmacists.

Correction to: Conducting a Time Trade-Off Study Alongside a Clinical Trial: A Case Study and Recommendations

The Open Access license, which previously read.

Abstract 2489: Enabling data access, sharing, collaborative and reproducible research: The Frederick National Laboratory for Cancer Research (FNLCR) data coordinating center

The Frederick National Laboratory for Cancer Research hosts a Data Coordinating Center and Toolset (the Metadata Designer plus Validator) hereafter referred to as the DCC that embodies a scalable, next-generation biological and cancer research data repository that is flexible, intuitive, and adaptive. The DCC provides integrated management of datasets across all deposited projects making its data more accessible and easily reusable by the cancer research community. The DCC stores and manages access to data, enabling researchers or data depositors to grant controlled access only to specific collaborators while maintaining a user-specified embargo on deposited datasets. The DCC enables a data access and sharing capability aimed to facilitate the development of new biological insights. The DCC implements the ISA (Investigation-Study-Assay) paradigm. The ISA framework provides a rich description of experimental metadata that is agnostic and irrespective of sample characteristic, technology or measurement type. It provides clear and simple sample-to-data relationships that enables resulting data and discoveries to be reproducible and reusable. These data are in the standard Investigation-Study-Assay tab-delimited format (ISA-TAB) format, which describes a scientific investigation, its study or studies, and each study's assay(s). The DCC portal is a public repository of experiment-related information describing cancer and biomedical research investigations. The portal can be used to browse, search, and access data from uploaded datasets. Through its stand-alone Toolset (Metadata Designer plus Validator), the DCC offers data depositors and researchers a simple interface to create and validate ISA-Tab compatible metadata associated with data generated in their research. Deriving new insights from aggregates of datasets and the need for reproducible research has never been more apparent. However, a fundamental requirement for these is a comprehensive metadata annotation and documentation of the research processes - an art that is elusive to researchers. Beyond the resultant publication is the data and metadata. These two basic ingredients are building blocks for a successful reproducible research project. In addition, appropriately curated data and metadata are invaluable resources for meta-analyses of seemingly disparate research studies. Further emphasizing the importance of these basic elements, are the principles of Findability, Accessibility, Interoperability, and Reusability (FAIR) - to guide data producers and publishers around obstacles and help maximize added-value gained from published studies. The DCC provides a much-needed resource to the research community for simplifying the sharing of data sets that meet these principles. The DCC portal is located at https://cssi-dcc.nci.nih.gov/cssiportal/

Citation Format: Paul Aiyetan, Paul Donovan, David Mott, Matthew Starr, Rajani Kuchipudi, Mahesh Yelisetti, Debra Hope, Corinne Zeitler, Uma Mudunuri, Andrew Quong. Enabling data access, sharing, collaborative and reproducible research: The Frederick National Laboratory for Cancer Research (FNLCR) data coordinating center [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2489.

Conducting a Time Trade-Off Study Alongside a Clinical Trial: A Case Study and Recommendations

Time trade-off (TTO) is an established method in health economics to elicit and value individuals' preferences for different health states. These preferences are expressed in the form of health-state utilities that are typically used to measure health-related quality of life and calculate quality-adjusted life-years in an economic evaluation. The TTO approach to directly elicit health-state utilities is particularly valuable when generic instruments (e.g. EQ-5D) may not fully capture changes in utility in a clinical trial. However, there is limited guidance on how a TTO study should be conducted alongside a clinical trial despite it being a valuable tool. We present an account of the design and development of a TTO study within a clinical trial as a case study. We describe the development of materials needed for the TTO interviews, the piloting of the TTO materials and interview process, and recommendations for future TTO studies. This paper provides a practical guide and reference for future applications of the TTO method alongside a clinical trial.

Asthma medication use among late midlife U.S. Adults

OBJECTIVE

Despite substantial prevalence of asthma, little is known about asthma in late midlife adults (50-64 years). The objective of this study was to examine the factors associated with the use of asthma medications among late midlife adults.

METHODS

Pooled data were obtained from the 2006 to 2010 Medical Expenditure Panel Survey. Medication use outcome variables include: (a) daily use of a preventive asthma medication and (b) use of more than three canisters of rescue inhalers in last 3 months. The Andersen Behavioral Model of Health Services Utilization was used to guide the selection of independent variables. Descriptive, unadjusted and adjusted logistic regression analyses were performed. Point estimates were weighted to the US civilian population and variance estimates were adjusted to obtain appropriate standard errors. All analyses were conducted using STATA (version 12).

RESULTS

A total of 1414 (weighted sample of 15,030,364) self-reported late midlife asthmatics were identified. About 31% of late midlife adults with asthma were using a preventive medication on a daily basis while 11% reported overusing acute medications. Adjusted analyses found that race, rurality and smoking were related to poor use of asthma medications among late midlife adults.

CONCLUSION

Results suggest that asthma medication use is far from optimal among vulnerable groups of late midlife US adults.

Bayesian QTL analyses using pedigreed families of an outcrossing species, with application to fruit firmness in apple

Proof of concept of Bayesian integrated QTL analyses across pedigree-related families from breeding programs of an outbreeding species. Results include QTL confidence intervals, individuals' genotype probabilities and genomic breeding values. Bayesian QTL linkage mapping approaches offer the flexibility to study multiple full sib families with known pedigrees simultaneously. Such a joint analysis increases the probability of detecting these quantitative trait loci (QTL) and provide insight of the magnitude of QTL across different genetic backgrounds. Here, we present an improved Bayesian multi-QTL pedigree-based approach on an outcrossing species using progenies with different (complex) genetic relationships. Different modeling assumptions were studied in the QTL analyses, i.e., the a priori expected number of QTL varied and polygenic effects were considered. The inferences include number of QTL, additive QTL effect sizes and supporting credible intervals, posterior probabilities of QTL genotypes for all individuals in the dataset, and QTL-based as well as genome-wide breeding values. All these features have been implemented in the FlexQTL(™) software. We analyzed fruit firmness in a large apple dataset that comprised 1,347 individuals forming 27 full sib families and their known ancestral pedigrees, with genotypes for 87 SSR markers on 17 chromosomes. We report strong or positive evidence for 14 QTL for fruit firmness on eight chromosomes, validating our approach as several of these QTL were reported previously, though dispersed over a series of studies based on single mapping populations. Interpretation of linked QTL was possible via individuals' QTL genotypes. The correlation between the genomic breeding values and phenotypes was on average 90 %, but varied with the number of detected QTL in a family. The detailed posterior knowledge on QTL of potential parents is critical for the efficiency of marker-assisted breeding.

Asthma medication use among U.S. adults 18 and older

BACKGROUND

Asthma is a chronic lung disease that currently affects an estimated 25 million Americans. One way to control the disease is by regular use of preventive asthma medications and controlled use of acute medications. However, little is known about adults with asthma and factors associated with their medication use.

OBJECTIVE

To identify factors associated with asthma medication use among U.S. adults aged 18 and older.

METHODS

Data were obtained from the 2006 to 2010 Medical Expenditure Panel Survey (MEPS). Medication use outcome variables include: a) daily use of a preventive asthma medication (yes/no) and b) overuse (3+) of acute inhalers in last 3 months (yes/no). The Andersen Behavioral Model of Health Care was used to guide the selection of independent variables. The independent variables were categorized as predisposing, enabling and medical need factors. Logistic regression models were used to examine the relationship between asthma medication use in adults with asthma. Point estimates were weighted to the U.S. non-institutionalized population, and standard errors were adjusted to account for the complex survey design.

RESULTS

Compared to Whites, minority adults 18 and older were less likely to use preventive asthma medication daily (Hispanic-OR: 0.72, CI: 0.54-0.96; African American-OR: 0.62, CI: 0.51-0.75 respectively). Similarly, Hispanic adults age 18 and older were at a significantly higher likelihood of overusing rescue medications compared to Whites (OR: 1.47, CI: 1.03-2.11). Non-metropolitan adults age 18 and older were more likely to overuse acute asthma medications than those from Metropolitan Statistical Area (OR: 1.57, CI: 1.15-2.16). Compared to older adults age 65 and over, late mid-life 50-64 year old adults were less likely to use a daily preventive asthma medication (OR: 0.67, CI: 0.54-0.83).

CONCLUSIONS

Race, rurality and age were important factors associated with poor asthma medication use in U.S. adults. Although this is a first step toward identifying factors that may influence the use of asthma medications, future studies are needed to develop and implement interventions to overcome issues to improve asthma care.

Low-temperature phase and morphology transformations in noble metal nanocatalysts

In situ real-time x-ray diffraction was used to study temperature-induced structural changes of 1-5 nm Au, Pt, and AuPt nanocatalysts supported on silicon substrates. Synchrotron-based x-ray diffraction indicates that the as-synthesized Au and Au(64)Pt(36) nanoparticles have a non-crystalline structure, while the Pt nanoparticles have the expected cubic structure. The nanoparticles undergo dramatic structural changes at temperatures as low as 120 °C. During low-temperature annealing, the Au and AuPt nanoparticles first melt and then immediately coalesce to form 4-5 nm crystalline structures. The Pt nanoparticles also aggregate but with limited intermediate melting. The detailed mechanisms of nucleation and growth, though, are quite different for the three types of nanoparticles. Most interestingly, solidification of high-density AuPt nanoparticles involves an unusual transient morphological transformation that affects only the surface of the particles. AuPt nanoparticles on silicon undergo partial phase segregation only upon annealing at extremely high temperatures (800 °C).

Development and evaluation of an instrument to measure community pharmacists' self-efficacy beliefs about communicating with Spanish-speaking patients

BACKGROUND

Hispanics are the largest growing population in the United States, and their use of prescription medications can be influenced by the education and counseling they receive from pharmacists. However, little is known about pharmacists' communication with patients who speak Spanish or factors that can influence such communication.

OBJECTIVES

The objective of the study was to develop and validate an instrument to measure pharmacists' self-efficacy in communicating with Spanish-speaking patients.

METHODS

An initial pool of 15 items developed from previous research and suggestions from communication experts and practicing pharmacists was subjected to cognitive interviewing. Nine retained items were administered to 1022 licensed pharmacists by mail survey. Summary statistics and exploratory factor analysis (EFA) were conducted. Retained factors were determined by the examination of eigenvalues and scree test results. Cronbach's alpha coefficients were calculated to assess internal consistency.

RESULTS

A total of 540 community pharmacists completed the survey. Item means ranged from 2.93±1.47 to 1.58±0.88 based on a 5-point scale (1: not at all confident to 5: extremely confident). EFA resulted in a 2-factor solution, accounting for 71% of the variance. The 2 factors consisted of health and drug information (alpha=0.92) and opening the encounter (alpha=0.75). The alpha for the overall scale was 0.88.

CONCLUSIONS

The results provide evidence to support the reliability and validity of an instrument to measure pharmacists' self-efficacy beliefs about communicating with Spanish-speaking patients in community practice. Practitioners and researchers may use this instrument to inform pharmacy education, pharmacy practice improvement, and research efforts around communicating with Spanish-speaking clients.

An in situ real-time x-ray diffraction study of phase segregation in Au-Pt nanoparticles

In situ real-time x-ray diffraction was used to study phase segregation and coarsening of Au-Pt nanoparticles supported on silica powder, and porous alumina membranes. Contrary to the expectations from the bulk phase diagram, silica supported Au-Pt nanoparticles have an alloyed structure that is preserved even after extensive annealing at temperatures as high at 700 degrees C. In stark contrast, alumina supported Au-Pt nanoparticles exhibit a rich phase behaviour that is sensitive to alloy composition and the details of the synthesis process. In particular, low-density as-prepared Au(41)Pt(59) nanoparticles exhibit the signature of incipient phase segregation that develops into full phase separation during annealing at high temperature.

Detection and evolution of resistance to the pyrethroid cypermethrin in Helicoverpa zea (Lepidoptera: Noctuidae) populations in Texas

The bollworm, Helicoverpa zea (Boddie), is a key pest of cotton in Texas. Bollworm populations are widely controlled with pyrethroid insecticides in cotton and exposed to pyrethroids in other major crops such as grain sorghum, corn, and soybeans. A statewide program that evaluated cypermethrin resistance in male bollworm populations using an adult vial test was conducted from 2003 to 2006 in the major cotton production regions of Texas. Estimated parameters from the most susceptible field population currently available (Burleson County, September 2005) were used to calculate resistance ratios and their statistical significance. Populations from several counties had statistically significant (P < or = 0.05) resistance ratios for the LC(50), indicating that bollworm-resistant populations are widespread in Texas. The highest resistance ratios for the LC(50) were observed for populations in Burleson County in 2000 and 2003, Nueces County in 2004, and Williamson and Uvalde Counties in 2005. These findings explain the observed pyrethroid control failures in various counties in Texas. Based on the assumption that resistance is caused by a single gene, the Hardy-Weinberg equilibrium formula was used for estimation of frequencies for the putative resistant allele (q) using 3 and 10 microg/vial as discriminatory dosages for susceptible and heterozygote resistant insects, respectively. The influence of migration on local levels of resistance was estimated by analysis of wind trajectories, which partially clarifies the rapid evolution of resistance to cypermethrin in bollworm populations. This approach could be used in evaluating resistance evolution in other migratory pests.

Low acute insulin secretory responses in adult offspring of people with early onset type 2 diabetes

The offspring of Pima Indians with early onset type 2 diabetes are at high risk for developing diabetes at an early age. This risk is greater among those whose mothers were diabetic during pregnancy. To define the metabolic abnormalities predisposing individuals in these high-risk groups to diabetes, we conducted a series of studies to measure insulin secretion and insulin action in healthy adult Pima Indians. In 104 normal glucose-tolerant subjects, acute insulin secretory response (AIR) to a 25-g intravenous glucose challenge correlated with the age at onset of diabetes in the mother (r = 0.23, P = 0.03) and, in multiple regression analyses, the age at onset of diabetes in the father (P = 0.02), after adjusting for maternal age at onset and after allowing for an interaction between these terms. In contrast, insulin action (hyperinsulinemic glucose clamp) did not correlate with the age at onset of diabetes in the parents. To determine whether early onset diabetes in the parents affected insulin secretion in the offspring across a range of glucose concentrations, responses to a stepped glucose infusion were measured in 23 subjects. Insulin secretion rates were lower in individuals whose mothers had developed diabetes before 35 years of age (n = 8) compared with those whose parents remained nondiabetic until at least 49 years of age (n = 15) (average insulin secretory rates: geometric mean [95% CI] 369 [209-652] vs. 571 [418-780] pmol/min, P = 0.007). Finally, the AIR was lower in individuals whose mothers were diabetic during pregnancy (n = 8) than in those whose mothers developed diabetes at an early age but after the birth of the subject (n = 41) (740 [510-1,310] vs. 1,255 [1,045-1,505] pmol/l, P < 0.02). Thus, insulin secretion is lower in normal glucose tolerant offspring of people with early onset type 2 diabetes. This impairment may be worsened by exposure to a diabetic environment in utero.

A calpain-10 gene polymorphism is associated with reduced muscle mRNA levels and insulin resistance

Previous linkage studies in Mexican-Americans localized a major susceptibility locus for type 2 diabetes, NIDDM1, to chromosome 2q. This evidence for linkage to type 2 diabetes was recently found to be associated with a common G-->A polymorphism (UCSNP-43) within the CAPN10 gene. The at-risk genotype was homozygous for the UCSNP-43 G allele. In the present study among Pima Indians, the UCSNP-43 G/G genotype was not associated with an increased prevalence of type 2 diabetes. However, Pima Indians with normal glucose tolerance, who have a G/G genotype at UCSNP-43, were found to have decreased rates of postabsorptive and insulin-stimulated glucose turnover that appear to result from decreased rates of glucose oxidation. In addition, G/G homozygotes were found to have reduced CAPN10 mRNA expression in their skeletal muscle. A decreased rate of insulin-mediated glucose turnover, or insulin resistance, is one mechanism by which the polymorphism in CAPN10 may increase susceptibility to type 2 diabetes mellitus in older persons.

Referral characteristics of primary care physicians for seizure patients

PURPOSE

To investigate primary care physicians' behavior with respect to referral patterns, antiepileptic drug (AED) initiation, and level of comfort in managing seizure patients.

METHODS

A cross-sectional descriptive study design was used for collecting and analyzing data. A 20-item survey was developed and mailed to 8,195 primary care physicians including family practitioners, internal medicine physicians, and obstetrics-gynecologists throughout the state of Ohio; 504 primary care physicians that interact regularly with epilepsy patients responded to the survey.

RESULTS

Two patterns of referral emerged. Data showed that the majority (n = 382) of physicians refer >/=50% of their patients, but a minority of physicians (n = 122) refer <50% of their patients. Differences between the two groups existed in three of the four research questions asked: who initiates AED therapy, comfort level, and percentage of patients referred to a neurologist. Influence of managed care on decision making was not different between the two groups.

CONCLUSIONS

A minority of primary care physicians rate themselves very comfortable with seizure patients. These same physicians refer a minority of their patients to a neurologist. As a whole, however, primary care physicians refer a majority of their seizure patients to a neurologist. Neurologists evaluate most seizure patients because most primary care physicians claim not to be extremely comfortable with evaluation and treatment of seizures. We conclude that neurologists play an essential role in the treatment of most seizure patients.

Radiotherapy for carcinoma of the posterior pharyngeal wall

Posterior pharyngeal carcinoma has an extremely poor prognosis regardless of the method of treatment. The purpose of this study was to assess the local control and survival in patients with carcinoma of the posterior pharyngeal wall treated with definitive radiotherapy and to determine prognostic factors which may be relevant to the current UICC staging classification. Between January 1991 and December 1995, 22 patients with a mean age of 60 years (range 44-82) received definitive radiotherapy, using a homogeneous technique, for carcinoma of the posterior pharyngeal wall. The median follow-up was 42 months (range 25-66). The overall 3-year survival and local control for the whole group was 50% and 73% respectively. Patients with early stage (T1 and T2) disease had a significantly better overall 3-year survival rate of 77% compared to 11% for patients with advanced stage (T3 and T4) disease (p=0.0010). Similarly, patients with early stage disease had a significantly improved 3-year local control rate compared to patients with more advanced stage disease (92% and 44% respectively, p=0.0080). Patients with node positive disease had an inferior survival rate of 29% compared to 60% for those with node negative disease though the difference did not reach statistical significance. In addition only one patient with initial node negative disease had isolated nodal relapse. There was no significant late morbidity. For patients with early stage disease we have obtained local control and survival rates comparable to other groups with a once daily, short fractionation radiotherapy scheme but with reduced morbidity. In late stage disease altered fractionation schemes should be considered in order to achieve better local control and survival. Isolated nodal relapse was not a significant problem in this cohort of patients. Outcome correlates with primary tumour size and this is reflected in the current UICC staging classification.

Pharmaceutical care and health outcomes in community settings: a matched pair analysis of perceptions of hypertensive patients versus pharmacists

This study aimed to: (1) assess the level of pharmaceutical care delivered by pharmacists, and (2) compare patients' and pharmacists' health related quality of life (HRQOL) assessments for patients receiving antihypertensive therapy as an indicator of the delivery of pharmaceutical care.

DESIGN

An exploratory, cross-sectional study using matched pair survey instruments.

SETTING

Columbus, Ohio.

PARTICIPANTS

Patients in a community setting prescribed antihypertensive medication and their pharmacists were selected for study participation.

INTERVENTIONS

Parallel surveys distributed to patients and their pharmacists.

MAIN OUTCOME MEASURES

Level of pharmaceutical care delivered by pharmacists, and perceived patient viewpoints on: clinical outcomes (blood pressure control, and side effects due to antihypertensive medication) and humanistic outcomes (overall, emotional and physical HRQOL) by patients and pharmacists.

RESULTS

Analysis of 52 useable matching surveys of pharmacists and patients indicated that nearly all pharmacists counsel patients and two thirds of pharmacists counsel and monitor drug therapy. This is consistent with providing the minimal OBRA 90 requirements. When comparing patient and pharmacist perceived patient clinical as well as humanistic outcomes, a high level of association was reported between the two groups.

CONCLUSIONS

The results of this study suggest that pharmacists are cognizant of patient clinical and humanistic outcomes and hence, they are in an excellent position to improve patient outcomes by making appropriate drug therapy changes.

Clinical variability of target volume description in conformal radiotherapy planning

PURPOSE

The pivotal step in radiation planning is delineation of the target volume and production of a treatment plan to encompass this. This study assesses the variation of physicians in creation of these volumes.

METHODS AND MATERIALS

Three radiologists and eight radiation oncologists outlined the gross tumour volume (GTV) on the planning CT scans of four cases with T3 bladder cancer. In addition, the radiation oncologists (RO) created a planning target volume according to a set protocol for all cases. Volumes were produced and comparison of these volumes and the position of the isocenters were analysed. In addition, the margins allowed were measured and compared.

RESULTS

There was a maximum variation ratio (largest to smallest volume outlined) of the GTV in the four cases of 1.74 among radiologists and 3.74 among oncologists. There was a significant difference (p = 0.01) in mean GTV between RO and the radiologists. The mean GTV of the RO exceeded the radiologists by a factor of 1.29 with a mean difference of 13.4 cm3. The variation ratio in PTV among oncologists ranged from 1.25 to 3.33. There was no significant difference in mean PTV values between the two groups of ROs divided by specialization in uro-oncology. The mean variation in location of the isocenter from the centroid of the radiologists' volume in the four cases was from 2.6 to 5.7 mm. There was, however, a wide range of values from 1.4 mm to 24.1 mm. Median margin per case ranged from 14.7 to 18.7 mm. Minimum margins allowed in each case varied from minus 7 mm to 9 mm.

CONCLUSION

This study demonstrates significant interphysician variability in producing target volumes and radiation plans for conformal radiotherapy. The scale of this difference is clearly of significance, with up to 3-fold variation in volumes delineated by clinicians. The factors leading to these differences will be further addressed. The existence of such variability, however, clearly needs to be accepted as a factor in the overall uncertainty analysis in conformal radiotherapy planning.

An autosomal genomic scan for loci linked to prediabetic phenotypes in Pima Indians

Type 2 diabetes mellitus is a common chronic disease that is thought to have a substantial genetic basis. Identification of the genes responsible has been hampered by the complex nature of the syndrome. Abnormalities in insulin secretion and insulin action predict the development of type 2 diabetes and are, themselves, highly heritable traits. Since fewer genes may contribute to these precursors of type 2 diabetes than to the overall syndrome, such genes may be easier to identify. We, therefore, undertook an autosomal genomic scan to identify loci linked to prediabetic traits in Pima Indians, a population with a high prevalence of type 2 diabetes. 363 nondiabetic Pima Indians were genotyped at 516 polymorphic microsatellite markers on all 22 autosomes. Linkage analyses were performed using three methods (single-marker, nonparametric multipoint [MAPMAKER/SIBS], and variance components multipoint). These analyses provided evidence for linkage at several chromosomal regions, including 3q21-24 linked to fasting plasma insulin concentration and in vivo insulin action, 4p15-q12 linked to fasting plasma insulin concentration, 9q21 linked to 2-h insulin concentration during oral glucose tolerance testing, and 22q12-13 linked to fasting plasma glucose concentration. These results suggest loci that may harbor genes contributing to type 2 diabetes in Pima Indians. None of the linkages exceeded a LOD score of 3.6 (a 5% probability of occurring in a genome-wide scan). These findings must, therefore, be considered tentative until extended in this population or replicated in others.

Familiality of physical and metabolic characteristics that predict the development of non-insulin-dependent diabetes mellitus in Pima Indians

Susceptibility to non-insulin-dependent diabetes mellitus (NIDDM) is largely genetically determined. In Pima Indians, obesity, insulin resistance, and a low acute insulin response (AIR) to an intravenous glucose infusion are each predictors of the disease. To ascertain whether these phenotypes are genetically determined, we estimated their familiality in nondiabetic Pima Indians with a maximum-likelihood method. Percentage body fat (PFAT) was highly familial (h2 =.76), whereas waist/ thigh circumference ratio (W/T ratio) was not significantly familial after controlling for PFAT (h2 = .16). AIR was also highly familial (h2 = .80 at 10 min), even after controlling for PFAT and insulin action (h2 = .70). Insulin action at physiologic plasma insulin concentrations was familial (h2 = .61) but less so after controlling for PFAT and W/T ratio (h2 = .38). At maximally stimulating insulin concentrations, insulin action was familial (h2 = .45) and was less influenced by controlling for PFAT and W/T ratio (h2 = .49). We conclude that in Pima Indians (1) PFAT and AIR are highly familial traits, (2) central distribution of fat is not a familial trait when controlled for PFAT, (3) 38%-49% of the variance in insulin action, independent of the effect of obesity, is familial, and (4) PFAT, AIR, and insulin action are useful traits to study genetic susceptibility to NIDDM. Because genetic parameter estimates are applicable only to the populations from which they were estimated, it is important to determine whether these estimates of familialities in Pima Indians can be confirmed in other populations before the utility of these traits in searching for NIDDM susceptibility genes in those populations can be fully advocated.

Glycogen synthase: a putative locus for diet-induced hyperglycemia

Inbred mouse strains fed a diabetogenic diet have different propensities to develop features analogous to type 2 diabetes mellitus. To define chromosomal locations that control these characteristics, recombinant inbred strains from diabetes-prone C57BL/6J (B/6J) and diabetes-resistant A/J strains were studied. Insulin levels and hyperglycemia correlated with two different regions of mouse chromosome 7 (two point LOD scores > 3.0). For insulin levels, 15 of 16 recombinant inbred strains were concordant with a region that contains the tubby mutation that results in hyperinsulinemia. For hyperglycemia, 19 of 23 strains were concordant with the D7Mit25 marker and 20 of 23 strains with the Gpi-1 locus on proximal mouse chromosome 7. Using more stringent criteria for hyperglycemia, 10 of 11 strains characterized as A/J or B/6J like were concordant with D7Mit25. This putative susceptibility locus is consistent with that of the glycogen synthase gene (Gys) recently suggested as a candidate locus by analyses of type 2 diabetes patients. Fractional glycogen synthase activity in isolated muscle was significantly lower in normal B/6J diabetic-prone mice compared with normal diabetic-resistant A/J mice, a finding similar to that reported in relatives of human patients with type 2 diabetes. These data, taken together, raise the possibility that defects in the Gys gene may in part be responsible for the propensity to develop type 2 diabetes.

Dynamic low-dose three-dimensional computed tomography: a preliminary study

Three-dimensional (3D) computed tomographic reformations have been used successfully as an adjunct to standard axial computed tomography (CT) in the evaluation of disorders affecting areas of complex anatomy. The basic requirements for high-quality 3D reformations are an absence of patient movement and narrow-width transaxial sections. Speed of examination is an important factor in optimizing image quality. One hundred examinations were performed on an IGE CT 9800 scanner. For bone studies, 80 mAs and, for certain soft tissues, 140 or 200 mAs were employed with 120 kVp. The advantages of such a "low-dose" technique are significant reduction in patient skin dose and a faster examination. The main disadvantage is a reduction in signal-to-noise ratio. The image quality obtained in 3D presentations has nevertheless been sufficient to enable all bony abnormalities to be identified. Three-dimensional examinations are now being performed routinely using a dynamic mode and this "low-dose" technique.

Impaired insulin-stimulated muscle glycogen synthase activation in vivo in man is related to low fasting glycogen synthase phosphatase activity

Insulin-mediated glycogen synthase activity in skeletal muscle correlates with the rate of insulin-mediated glycogen deposition and is reduced in human subjects with insulin resistance. To assess the role of glycogen synthase phosphatase as a possible mediator of reduced glycogen synthase activity, we studied 30 Southwestern American Indians with a broad range of insulin action in vivo. Percutaneous biopsies of the vastus lateralis muscle were performed before and during a 440-min euglycemic clamp at plasma insulin concentrations of 89 +/- 5 and 1,470 +/- 49 microU/ml (mean +/- SEM); simultaneous glucose oxidation was determined by indirect calorimetry. After insulin stimulation, glycogen synthase activity was correlated with the total and nonoxidative glucose disposal at both low (r = 0.73, P less than 0.0001; r = 0.68, P less than 0.0001) and high (r = 0.75, P less than 0.0001; r = 0.74, P less than 0.0001) plasma insulin concentrations. Fasting muscle glycogen synthase phosphatase activity was correlated with both total and nonoxidative glucose disposal rates at the low (r = 0.48, P less than 0.005; r = 0.41, P less than 0.05) and high (r = 0.47, P less than 0.05; r = 0.43, P less than 0.05) plasma insulin concentrations. In addition, fasting glycogen synthase phosphatase activity was correlated with glycogen synthase activity after low- (r = 0.47, P less than 0.05) and high- (r = 0.50, P less than 0.01) dose insulin stimulations. These data suggest that the decreased insulin-stimulated glucose disposal and reduced glycogen synthase activation observed in insulin resistance could be secondary to a low fasting glycogen synthase phosphatase activity.

Regulation of glycogen synthase and phosphorylase activities by glucose and insulin in human skeletal muscle

We examined the insulin dose-response characteristics of human muscle glycogen synthase and phosphorylase activation. We also determined whether increasing the rate of glucose disposal by hyperglycemia at a fixed insulin concentration activates glycogen synthase. Physiological increments in plasma insulin but not glucose increased the fractional activity of glycogen synthase. The ED50: s for insulin stimulation of whole body and forearm glucose disposal were similar and unaffected by glycemia. Glycogen synthase activation was exponentially related to the insulin-mediated component of whole body and forearm glucose disposal at each glucose concentration. Neither insulin nor glucose changed glycogen phosphorylase activity. These results suggest that insulin but not the rate of glucose disposal per se regulates glycogen synthesis by a mechanism that involves dephosphorylation of glycogen synthase but not phosphorylase. This implies that the low glycogen synthase activities found in insulin-resistant states are a consequence of impaired insulin action rather than reduced glucose disposal.

Free fatty acid metabolism and obesity in man: in vivo in vitro comparisons

We have examined the relationship of free fatty acid (FFA) turnover and lipid oxidation rates in vivo to the size of body triglyceride stores and compared these findings with the in vitro lipolytic rates of isolated abdominal fat cells. The studies were performed in 20 Pima Indian women 18 to 35 years of age, both lean and obese. FFA turnover rate was measured using a 1-14C-palmitate infusion, lipid oxidation rate by indirect calorimetry using a ventilated hood, body composition by underwater weighing with correction for residual lung volume, and fat cell lipolytic rates in vitro by published methods. Both FFA turnover and lipid oxidation rates, expressed per kg of body fat, decreased with increasing degree of obesity (as measured by percent body fat) (r = -0.90, and r = -0.75, P less than or equal to 0.0001, respectively). In contrast, the rate of lipolysis determined in vitro, expressed per kg of fat, increased with increasing degree of obesity (r = 0.58, P less than 0.01). A ratio of FFA turnover/lipolysis, which directly compares these in vivo and in vitro measurements, decreased significantly with increases in the degree of obesity (r = -0.81, P less than or equal to 0.0001). Furthermore, there were no positive correlations between the measures of in vivo FFA metabolism and in vitro lipolysis when both were expressed per fat mass, per fat cell number, or per fat cell surface area. The in vivo data also demonstrated that lipid oxidation could only account for 50% of the FFA disappearance rate. While lipid oxidation rate adjusted to the metabolic size increased with increasing plasma FFA concentration (r = 0.75, P less than 0.0003), the nonoxidative component of the FFA turnover failed to increase with increases in plasma FFA concentration (P = 0.5). We conclude that FFA is not available in vivo in proportion to the size of the triglyceride stores. The reason for this is not due to an inability of fat cells to release their stored triglyceride as assessed in vitro. Hence, in vitro measurements of fat cell lipolysis cannot be used to directly predict in vivo FFA metabolism. The large nonoxidative FFA disposal is likely to be important in the regulation of plasma FFA concentrations.

Increased resting metabolic rates in obese subjects with non-insulin-dependent diabetes mellitus and the effect of sulfonylurea therapy

Obese subjects with non-insulin-dependent diabetes mellitus (NIDDM) lose weight soon after diagnosis and tend to gain weight during hypoglycemic therapy. One explanation for these weight shifts is the change in caloric loss from glycosuria. We compared 24 obese Pima Indians with NIDDM to 24 Pima Indians with normal glucose tolerance to determine whether resting metabolic rate changes may be an additional factor influencing the weight shifts. The diabetic and nondiabetic subjects were equally obese, body fat 38 +/- 1% versus 37 +/- 1% (mean +/- SEM), respectively, as determined by densitometry. In the morning after an overnight fast, resting metabolic rate (RMR) was measured by indirect calorimetry. The mean RMR of the diabetic subjects, 32.9 +/- 0.5 kcal/day X kg fat-free mass (FFM), was 5% higher than that of the nondiabetic subjects, 31.4 +/- 0.5 kcal/day X kg FFM (P less than 0.05). In nine of the diabetic subjects, 6 wk of tolazamide therapy was associated with reductions in mean FPG, 253 +/- 16 to 144 +/- 14 mg/dl (P less than 0.01), mean daily urine glucose loss, 128 +/- 26 to 11 +/- 4 g (P less than 0.01), and mean RMR, 31.9 +/- 0.8 to 30.2 +/- 0.6 kcal/day X kg FFM (P less than 0.04). Weight of the subjects was maintained constant from beginning to end of therapy (106.5 +/- 9.6 versus 108.1 +/- 9.9 kg) by decreasing daily calorie intake from 3070 +/- 103 to 2784 +/- 163 kcal (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of short-term overfeeding on adipocyte metabolism in Pima Indians

The effects on adipocyte metabolism of increasing daily caloric intake by approximately 60% for 14 days was studied in seven nondiabetic moderately obese southwestern Native American Indians. Mean body weight increased by 3.0 +/- 0.3 kg, without any change in average size of isolated abdominal adipocytes. Overfeeding resulted in a 58% increase (P less than 0.01) in mean fasting plasma insulin concentration, whereas fasting plasma glucose concentration remained constant. Basal and maximum (8 nmol/L) insulin-stimulated glucose transport rates by isolated adipocytes increased by 83% (P less than 0.02) and 110% (P less than 0.01), respectively, after overfeeding, associated with an increase of 118% (P less than 0.01) in the incremental response to maximal insulin stimulation. However, no differences in either the sensitivity (ED50 of insulin for the stimulation of glucose transport) or the responsiveness (percent stimulation by insulin) of glucose transport were seen in isolated adipocytes as a result of overfeeding. Maximum insulin-stimulated total glucose utilization rates by isolated adipocytes incubated at 5.5 mmol/L glucose were 63% greater after overfeeding, due to increases in lactate formation, triglyceride synthesis, and CO2 production. Mono125I-(Tyr A14)-insulin binding per cell and per cell surface area was similar before and after overfeeding. The lipolytic rate of isolated adipocytes, in the absence and presence of 25 nmol/L and 2 mumol/L isoproterenol, was decreased by 75% (P less than 0.02), 45% (P less than 0.05), and 27% (P less than 0.05), respectively, after overfeeding. However, overfeeding did not result in a significant difference in the sensitivity of antilipolysis to insulin.(ABSTRACT TRUNCATED AT 250 WORDS)

Evidence for reduced thermic effect of insulin and glucose infusions in Pima Indians

Several authors have reported a reduced thermic effect of food in obese subjects. The hyperinsulinemic-euglycemic clamp technique has been used to measure one component of the thermic effect of food, insulin and insulin-mediated glucose disposal. We used this technique to measure the thermic responses to insulin and glucose infusions in 120 glucose-tolerant Pima Indians, a population with a high prevalence of obesity. During high-dose insulin infusions (400 mU/m2 per min) the measured increase in energy expenditure (MEE), 150 +/- 6 cal/min, was greater than the predicted increase in energy expenditure (PEE), 72 +/- 2 cal/min, for glucose storage as glycogen. During low-dose insulin infusions (40 mU/m2 per min) the mean MEE, 6 +/- 5 cal/min, was not significantly different from zero and was not greater than the mean PEE, 9 +/- 1 cal/min. These data were in contrast to results obtained from Caucasians by others and suggested a markedly reduced thermic effect of low-dose insulin and glucose infusions in Pima Indians. We also studied 23 glucose-tolerant male Caucasians and compared their results with the results from male Indians matched for glucose storage rates and obesity. The results showed that the thermic response to insulin and glucose infusions was similar in the two racial groups during high-dose insulin infusions but was markedly reduced in the Indians compared with the Caucasians during low-dose insulin infusions.

Relationships between insulin secretion, insulin action, and fasting plasma glucose concentration in nondiabetic and noninsulin-dependent diabetic subjects

The relationships between insulin secretion, insulin action, and fasting plasma glucose concentration (FPG) were examined in 34 southwest American Indians (19 nondiabetics, 15 noninsulin-dependent diabetics) who had a broad range of FPG (88-310 mg/100 ml). Fasting, glucose-stimulated, and meal-stimulated plasma insulin concentrations were negatively correlated with FPG in diabetics but not in nondiabetics. In contrast, fasting and glucose-stimulated plasma C-peptide concentrations did not decrease with increasing FPG in either group and 24-h urinary C-peptide excretion during a diet of mixed composition was positively correlated with FPG for all subjects (r = 0.36, P less than 0.05). Fasting free fatty acid (FFA) was correlated with FPG in nondiabetics (r = 0.49, P less than 0.05) and diabetics (r = 0.77, P less than 0.001). Fasting FFA was also correlated with the isotopically determined endogenous glucose production rate in the diabetics (r = 0.54, P less than 0.05). Endogenous glucose production was strongly correlated with FPG in the diabetics (r = 0.90, P less than 0.0001), but not in the nondiabetics. Indirect calorimetry showed that FPG was also negatively correlated with basal glucose oxidation rates (r = -0.61, P less than 0.001), but positively with lipid oxidation (r = 0.74, P less than 0.001) in the diabetics. Insulin action was measured as total insulin-mediated glucose disposal, glucose oxidation, and storage rates, using the euglycemic clamp with simultaneous indirect calorimetry at plasma insulin concentrations of 135 +/- 5 and 1738 +/- 59 microU/ml. These parameters of insulin action were significantly, negatively correlated with FPG in the nondiabetics at both insulin concentrations, but not in the diabetics although all the diabetics had markedly decreased insulin action. We conclude that decreased insulin action is present in the noninsulin-dependent diabetics in this population and marked hyperglycemia occurs with the addition of decreased peripheral insulin availability. Decreased peripheral insulin availability leads to increased FFA concentrations and lipid oxidation rates (and probably also increased concentrations of gluconeogenic precursors) that together stimulate gluconeogenesis, hepatic glucose production, and progressive hyperglycemia.

Correlation between muscle glycogen synthase activity and in vivo insulin action in man

We have studied the relationship between in vivo insulin-mediated glucose disposal rates, muscle glycogen content, and muscle glycogen synthase activity in 25 southwest American Indians with normal glucose tolerance and with varying degrees of glucose intolerance. Insulin-mediated glucose disposal (M) was measured by using the hyperinsulinemic euglycemic clamp technique at plasma insulin concentrations of 134 +/- 7 and 1709 +/- 72 microU/ml, with simultaneous indirect calorimetry to assess glucose oxidation and storage rates. Muscle glycogen content and glycogen synthase activity were measured in percutaneous muscle biopsy samples obtained from the vastus lateralis muscle before and after the euglycemic clamp procedure. The results showed that muscle glycogen synthase activity at the end of the euglycemic clamp was well correlated with insulin-mediated glucose storage rates at both low (r = 0.50, P less than 0.02) and high (r = 0.78, P less than 0.0001) insulin concentrations; and also correlated with M (r = 0.66, P less than 0.001 and r = 0.76, P less than 0.0001). Similar correlations were observed between the change in muscle glycogen synthase activity and glucose storage rates and M. The change in muscle glycogen synthase activity correlated with the change in muscle glycogen content (r = 0.46, P less than 0.03) measured before and after the insulin infusions. The change in muscle glycogen content did not correlate with glucose storage rates or M. The data suggest the possible importance of glycogen synthesis in muscle in determining in vivo insulin-mediated glucose disposal rates in man.

Relationship between obesity and maximal insulin-stimulated glucose uptake in vivo and in vitro in Pima Indians

Previous studies have left unanswered whether human obesity, independent of glucose intolerance, is associated with a "postreceptor" defect in insulin action. We have studied the relationship between the degree of obesity (as estimated by underwater weighing) and the maximal insulin-stimulated glucose disposal rate (M) in vivo in 52 glucose-tolerant Pima Indian males. The relationship was examined independently of differences in age and maximal oxygen uptake (an estimate of "physical fitness"). The maximal insulin-stimulated glucose transport rate (MTR) was also measured in isolated abdominal adipocytes from the same subjects to determine whether differences in M could be explained by differences in glucose transport. The results showed that there was a large variance in M and MTR among these glucose-tolerant subjects. M was better correlated with glucose storage rates than with oxidation rates, as estimated by indirect calorimetry. The most obese subjects had only a 20% lower mean M and 30% lower MTR than the most lean subjects. The lower M in the obese subjects was due to both lower glucose oxidation and storage rates. There was no significant, independent correlation between age or degree of obesity and M or MTR. The maximal oxygen uptake (VO2 max) appeared to independently account for 20% of the variance observed in M. MTR was only weakly correlated with M (r = 0.36, P less than 0.02). We concluded that differences in M in these glucose-tolerant subjects must be explained by factor(s) other than maximal oxygen uptake, age, maximal insulin-stimulated glucose transport in vitro, or degree of adiposity per se.

Impedance plethysmography: evaluation of a simplified system of electrodes for the measurement of blood flow in the lower limb

Venous occlusion plethysmography was used to measure the flow of blood into the lower limbs of 30 normal volunteers. An impedance plethysmograph, using disposable point electrodes, was compared with a mercury in Silastic strain gauge plethysmograph in 20 subjects. The effect of changes in the configuration of the point electrodes was studied in 10 subjects. Impedance plethysmography was shown to be reproducible, and one particular configuration of point electrodes was shown to be superior to the others.

Comparison of impedance and strain gauge plethysmography in the measurement of blood flow in the lower limb

Simultaneous measurement of the flow of blood in the calf in 24 normal volunteers by impedance and mercury strain gauge plethysmography has revealed a systematic difference in the results from the two methods. Possible reasons for this discrepancy are discussed.