Emma Fernandez-Repollet

Involving Minority and Underrepresented Women in Clinical Trials: The National Centers of Excellence in Women's Health

Recent attention to reducing health disparities among population groups has focused on the need to include in clinical studies, especially clinical trials, participants who represent the diversity of the populations to which study results will be applied. While scientists generally applaud the goal of broadening the characteristics of participants in clinical trials, they are faced with multiple challenges as they seek to include historically underrepresented populations in their research. This article examines the historical and sociocultural context of participation by underrepresented groups, especially women and minorities, in clinical trials, identifies major barriers and challenges facing researchers, and suggests strategies for meeting these challenges. The article draws upon the experiences of the investigators affiliated with the National Centers of Excellence of Womens Health (CoEs).

Development of Clinical Standards for Flow Cytometry

Flow cytometers are instruments that can determine multiparameter data simultaneously and have a great potential in providing unique information about cells. To transfer this potential to the clinical laboratory, the development and the proper use of standards and calibrators are required to ensure comparability and reproducibility of data from different flow cytometers. Although there are a number of types of standards for flow cytometry, each has its specifically designed purpose to ensure that data from this complex instrument are accurate, precise, and reproducible among instruments over time.

Quantification of EGFP expression on Molt-4 T cells using calibration standards.

Enhanced green fluorescent protein (EGFP) is used extensively to assess gene expression on cells; however, quantification of this expression by flow cytometry has been limited by the unavailability of calibration standards. Thus, we characterized the response of an experimental set of EGFP calibration standards to environmental changes and then quantitate the expression of EGFP, in molecules of equivalent soluble fluorochrome (MESF) units, of a transfected Molt‐4 T cell line by flow cytometry.

Role of water balance in the enhanced potassium excretion and hypokalaemia of rats with diabetes insipidus.

1. The role of water balance in the hypokalaemia of rats with diabetes insipidus (DI rats) was studied. 2. After a 3‐day balance study DI rats had a lower muscle potassium content, and plasma [K+], and the urinary excretion of potassium in response to oral KCl loading was reduced when compared to normal rats. The hypokalaemia was found to be associated with elevated concentrations of potassium in renal medulla and papilla when compared to values in normal Long‐Evans rats. 3. During a 9‐day balance study urinary potassium excretion was higher than that of normal rats on days 1‐3, but not different on days 4‐9; this transient elevation was observed in DI rats on normal, high and low potassium diets. On a low potassium diet the urinary potassium excretion of DI rats fell to minimal levels, making unlikely the existence of a renal defect in potassium handling. 4. Muscle potassium content and plasma [K+] were normal after 9 days in metabolism cages. This spontaneous reversal of the hypokalaemia of DI rats was associated with increased water content of renal medulla and papilla, and decreased potassium concentration in these zones. 5. The effect of acute mild dehydration on potassium handling of DI rats was evaluated. Water deprivation for 1‐8 hr was sufficient to raise the urinary potassium excretion of DI rats above that of DI rats drinking ad lib. Renal tissue [K+] was significantly increased after 8 hr of dehydration. Water deprivation also enhanced the response of DI rats to an oral KCl load. Two days of chronic dehydration in the form of water rationing also significantly enhanced the urinary potassium excretion of DI rats. 6. These data suggest that chronic mild dehydration may be responsible for the modest potassium deficiency observed in DI rats via alterations in renal tissue [K+] and consequently in urinary potassium excretion. Correction of dehydration during prolonged periods in metabolism cages may account for the spontaneous reversal of the hypokelaemic condition.

Chapter 35 Standardization for Flow Cytometry

Publisher Summary This chapter focuses on the comprehensive perspective of standardization, specifically identifying cell population patterns, quantitating fluorescence intensities, and determining the antibody binding capacity. Attempts at standardizing these parameters have involved descriptions of weak or strong light scatter to describe size and degree of granularity, as well as references to dim or strong fluorescence intensities. The need for developing effective standardization procedures is magnified by the dramatic increase in commercial and custom-built flow cytometers, which collect four, five, or more parameters. The sensitivity and accuracy in comparing cell population patterns over these parameters require that proper standards are available to normalize the performance of the instruments. In turn, the standards need to have characteristics that closely resemble the samples being analyzed, including apparent size, granularity, fluorescence spectra, and intensity. The chapter reviews the status of flow cytometry standardization and suggests several new standardization procedures.

Effects of Endogenous Antidiuretic Hormone (ADH) on Macrophage Phagocytosis

Although several studies have indicated that antidiuretic hormone (ADH) enhances the phagocytic function of the reticuloendothelial system (RES) in shock syndromes, it remains unknown what influence ADH exerts upon the individual phagocytic components of this system. The present investigation was designed to evaluate the effects of endogenous ADH on the phagocytic activity of peritoneal macrophage cells. As a phagocytic stimuli, fluorescent methacrylate microbeads were injected intraperitoneally into Brattleboro (ADH deficient) and normal Long Evans rats in the presence and absence of exogenous ADH. Peritoneal cells were harvested 19-22 hr after the administration of the microbeads and the percent phagocytosis was determined in macrophage cells using a fluorescence-activated cell sorter (FACS II). Our results indicate that the percentage of peritoneal macrophages ingesting the fluorescent methacrylate microbeads was significantly reduced in the absence of ADH (Brattleboro rats: 5.4 +/- 0.6% versus Long Evans rats: 16.8 +/- 2.3%; p less than 0.001). In addition, our data demonstrate that exogenous administration of ADH significantly enhanced macrophage phagocytosis in Brattleboro (14.7 +/- 2.2%) and normal Long Evans (49.6 +/- 4.5%) rats. These data suggest, for the first time, that endogenous ADH might play a modulatory role in the phagocytic activity of a specific component of the RES, namely, the macrophage cell.

In Vivo Effects of Prostaglandin E2 and Arachidonic Acid on Phagocytosis of Fluorescent Methacrylate Microbeads by Rat Peritoneal Macrophages

Several studies have suggested that prostaglandin E2 (PGE2) might influence the phagocytic activity of macrophage cells. The present study was designed to examine the in vivo effects of PGE2, the prostaglandin synthesis inhibitor meclofenamate, the prostaglandin precursor arachidonic acid, and the biologically inactive fatty acid 11,14,17-eicosatrienoic acid on phagocytosis by peritoneal macrophage cells in the rat. Following 3 days of treatment with either agent, fluorescent methacrylate microbeads were injected intraperitoneally into all rats. Peritoneal exudates were harvested after administration of the microbeads and the percent phagocytosis determined in macrophage cells using a fluorescence-activated cell sorter (FACS II). The administration of PGE2 was associated with a significant decrease in the percentage of peritoneal macrophages ingesting the fluorescent methacrylate microbeads. In contrast, treatment with arachidonic acid or 11,14,17-eicosatrienoic acid significantly enhanced the percentage of phagocytic macrophage cells. A significant increase in the number of macrophages undergoing phagocytosis of the methacrylate microbeads was also observed in rats treated with meclofenamate. This later observation, taken together with the inhibitory effect induced by PGE2 on macrophage phagocytosis, points to a potential modulator role of PGE2 on the phagocytic activity of macrophages. These data also suggest that arachidonic acid might influence macrophage phagocytosis by a mechanism independent of PGE2.

SODIUM AND POTASSIUM BALANCE IN THE BRATTLEBORO RAT

Since its discovery in 1961,l it has become apparent that the Brattleboro (DI) rat is a useful model for the study of a variety of physiological problems in addition to the obvious one of the role of antidiuretic hormone (vasopressin, ADH) in urine concentration and water balance. In the study of the control of extracellular fluid volume and electrolyte balance, in particular, the DI rat offers a unique opportunity to observe the spontaneous interaction of homeostatic mechanisms when a single disturbance, namely the absence of ADH, has been introduced. This review will attempt to present a comprehensive description of the state of sodium and potassium balance in the DI rat. Although some data exist on the handling of other electrolytes 51, 54 these have not been studied extensively. Mention will also be made of the multiple factors that may influence electrolyte balance in the Brattleboro rat. New data, obtained by Opava-Stitzer and Fernhdez-Repollet, will be included when relevant.

Setting a Local Research Agenda for Women's Health: The National Centers of Excellence in Women's Health

Although womens health research expanded greatly in the past 10 years, significant gaps in knowledge remain. Prioritization and promotion of research will help assure continuing progress in closing such gaps and improving the health of women. Although a comprehensive agenda for the new millennium has been developed at the national level, the process for establishing a local research agenda is not well defined. The purpose of this study was to describe criteria for and barriers to establishing a local research agenda in womens health. A secondary aim was to describe mechanisms for identifying womens health researchers and for facilitating multidisciplinary research. Directors of Research at National Centers of Excellence in Womens Health (CoEs) (n = 18) were surveyed by mail for this information. The results indicate that the local research agenda should emphasize health issues that are prevalent in women, research that is likely to establish treatment, psychosocial/cultural factors, and quality of life issues. The process of setting a research agenda should include input from the communities served as well as from scientists. Critical evaluation of scientific strengths and weaknesses is an essential preliminary step in prioritizing research opportunities in order to implement and evaluate a research agenda in womens health.

Effects of summer internship and follow-up distance mentoring programs on middle and high school student perceptions and interest in health careers

BackgroundMinorities are underrepresented in health professions and efforts to recruit minority students into health careers are considered a way to reduce health disparities. There is little research about the effectiveness of these programs, other than satisfaction. This study aimed to measure program effects on student understanding of and interest in health careers.MethodsStudents took a career interest inventory, completed a scale measuring their self-reported understanding and interest in health careers, and wrote essays about health careers before and after completing a 1 week on campus internship on health careers and after a 9 month follow up distance mentoring program where they continued to interact with university faculty by videoconference about career options. Changes in inventory, scale, and essay scores were analyzed for changes over time using Wilcoxon and Mann-Whitney tests.ResultsInventory scores were unchanged over time, but scale and essay scores trended upward significantly post internship and mentoring.ConclusionHealth career education and mentoring programs can positively affect student knowledge of health careers and their attitudes about them. The study’s methods extend measures of program impact beyond satisfaction.