26 Virtual strabismus clinic: an alternative model of care during the COVID-19 pandemic

Addenbrooke's Hospital introduced a virtual strabismus clinic in March 2021 to manage patient care during the COVID-19 pandemic. This study aims to explore the feasibility and utility of this care model by evaluating its effectiveness in delivering patient care.Clinic data from April 2021 to April 2022 were retrospectively analysed, including patient demographics, referral information and outcomes. All patients underwent an initial assessment by a specialist orthoptist, preceding virtual review by a consultant ophthalmologist.The clinic saw 114 patients between the ages of 12 and 95 during this period, with an increasing number of patients seen per month. Within two months of the clinic's inception, wait times reduced by 59%: from 30.2 weeks to 12.5 weeks, remaining constant thereafter. Most referrals came from optometrists, with diplopia and identification of new or recurring strabismus being the most common complaint. Virtual review outcome varied significantly: 30.7% of patients were discharged, 16.7% listed for surgery, 34.2% received a repeat FTF review and a further 18.4% received a review virtually.Following its inception, the virtual clinic was able to effectively accommodate patients despite capacity restraints. This was partly achieved through the effective utilisation of specialised orthoptists. Subsequent virtual review by a consultant ophthalmologist achieved positive patient outcomes.Virtual clinics provide an opportunity to optimise patient care and maximise efficiency of clinical input. If applied appropriately, this model of patient care may reduce the NHS burden, improving wait times to facilitate faster intervention. Increasing consultant availability permits the treatment of a greater number of patients.

The Influence of Contested Racial Identity and Perceived Everyday Discrimination Exposure on Body Mass Index in US Adults

Contested racial identity-the discrepancy between one's self-identified race and socially assigned race-is a social determinant of health and may contribute to overweight and obesity. Obesity is associated with a host of short- and long-term health conditions, including cardiovascular disease, a leading cause of death. Individuals racialized as Black, Hispanic, and Latino are at the greatest risk of obesity. Previous research indicates that experiencing interpersonal discrimination is associated with higher body mass index (BMI) in adults, and individuals with a contested racial identity are disproportionately exposed to interpersonal discrimination. However, the association between BMI and contested racial identity is unknown. This cross-sectional study measured the relationship between contested racial identity and perceived everyday discrimination on BMI in a nationally representative sample of US adults. Contested racial identity was measured with a binary variable indicating agreement between participants' self-identified race and socially assigned race. Weighted unadjusted and adjusted multiple linear regression models quantified the associations between BMI and contested racial identity with and without the mean discrimination score. Covariates included nativity status, income, education, racial identity salience, gender, and age. Among 1689 participants, 18.3% had a contested racial identity. Contested identity was associated with significantly higher BMI (β = 1.01, 95% CI = 0.06, 1.92), but the relationship was attenuated when adjusting for interpersonal discrimination, suggesting that individuals with contested identity may face a greater risk of obesity due to their disproportionately high exposure to interpersonal racial discrimination. Further research is needed to elucidate the impact of racism on BMI and obesity risk.

A193 PERCEIVED BARRIERS TO GLUTEN-FREE FOOD ACCESS ON-CAMPUS EXPERIENCED BY STUDENTS FROM DIFFERENT CANADIAN UNIVERSITIES AND COLLEGES

Background

Students with gluten-related disorders (GRD), a spectrum of conditions including celiac disease (CeD) and non-celiac wheat sensitivity (NCWS), often experience challenges when accessing gluten-free (GF) foods.

Aims

To identify barriers perceived by students with GRD to access GF products on-campus of universities and colleges across Canada.

Methods

We conducted a cross sectional survey using the RedCap platform and distributed it to the Canadian Celiac Association community. We included students who reported adopting a GFD for various reasons including CeD and other GRD. We collected data on adherence to the GFD using a validated questionnaire (CDAT), presence of perceived barriers to follow a GFD while dining on campus, persistent symptoms, and altered quality of life. Continuous data are expressed as median (IQR), and categorical data as proportions of patients. Mann-Whitney U and Chi2 with Fisher correction were used to assess differences between groups.

Results

Seventy nine students responded to the survey (5% male and median age = 25 yrs) and 78 had complete data for analysis. Of the 78 students, 52 (66.6%) reported a diagnosis of CeD, while 26 were adopting a GFD for other reasons (non-CeD). The majority were enrolled in university programs (72/78) and 18% were living on-campus. Almost 90% reported difficulties maintaining a GFD while dining on-campus. Similar proportion of CeD and non-CeD reported eating gluten accidentally (75% vs 80%), while 15% reported eating gluten intentionally on-campus at least a few times per week. This was observed more frequently in non-CeD compared with students with CeD (61% vs 17%; p=0.04). Barriers identified in CeD versus non-CeD groups were related to a reduced GF-food variety (48% vs 69%), lack of availability of GF food (21% vs 46%) and increased cost (46% vs 81%) compared with gluten-containing counterparts. The majority of participants were concerned whether the food available on-campus was truly GF (80% vs 54%) as they reported foods not properly labelled. The majority of participants considered their overall health (79%) and quality of life (65%) was fair to terrible while dining on campus. During the pandemic, 76% of them perceived that it was easier to stick to a GF diet.

Conclusions

Students from various universities and colleges across Canada experience barriers to access GF food on-campus. This has a significant impact on their overall health and quality of life. Proper food labeling, GF certification and improving the variety of GF food on-campus are options for improvement.

Funding Agencies

None

Assessing equity in health, wealth, and civic engagement: a nationally representative survey, United States, 2020

BACKGROUND

The principle of equity is fundamental to many current debates about social issues and plays an important role in community and individual health. Traditional research has focused on singular dimensions of equity (e.g., wealth), and often lacks a comprehensive perspective. The goal of this study was to assess relationships among three domains of equity, health, wealth, and civic engagement, in a nationally representative sample of U.S. residents.

METHODS

We developed a conceptual framework to guide our inquiry of equity across health, wealth, and civic engagement constructs to generate a broad but nuanced understanding of equity. Through Ipsos' KnowledgePanel service, we conducted a cross-sectional, online survey between May 29-June 20, 2020 designed to be representative of the adult U.S.

POPULATION

Based on our conceptual framework, we assessed the population-weighted prevalence of health outcomes and behaviors, as well as measures of wealth and civic engagement. We linked individual-level data with population-level environmental and social context variables. Using structural equation modeling, we developed latent constructs for wealth and civic engagement, to assess associations with a measured health variable.

RESULTS

We found that the distribution of sociodemographic, health, and wealth measures in our sample (n = 1267) were comparable to those from other national surveys. Our quantitative illustration of the relationships among the domains of health, wealth, and civic engagement provided support for the interrelationships of constructs within our conceptual model. Latent constructs for wealth and civic engagement were significantly correlated (p = 0.013), and both constructs were used to predict self-reported health. Beta coefficients for all indicators of health, wealth, and civic engagement had the expected direction (positive or negative associations).

CONCLUSION

Through development and assessment of our comprehensive equity framework, we found significant associations among key equity domains. Our conceptual framework and results can serve as a guide for future equity research, encouraging a more thorough assessment of equity.

978 Improving Satisfaction in Patients with Learning Disabilities

Aim

Patients with learning disabilities (LD) are less satisfied because they do not fully understand their surgical management. Poor communication between doctors & LD patients leaves them unhappy & reluctant to seek further help. We aimed to improve satisfaction in 90% of patients.

Method

In one year in a midlands DGH 201 patients with an LD were admitted. Interviews were conducted which highlighted key problems. Multiple ideas were reviewed, and the simple but effective intervention was a brightly coloured prompt sheet with 4 questions placed in the patient notes: Have you explained:

A simple scale tracked the patient & carer satisfaction over 8 weeks as the prompt sheets were introduced to patient notes by the learning disability nurses.

Results

A 90% increase in patient satisfaction was not achieved but considerable positive feedback was. Moreover, the LD nurses witnessed an increased use of hospital passports among doctors as well as improved patient-doctor communication. A small target population restricts the rapid collection of large amounts of data. The patient satisfaction measure was qualitative, and a 10-point scale would have detailed smaller changes. Lack of carer continuity also made it difficult to collect consistent data.

Conclusions

The role of learning disability nurses is key to improving patient understanding and satisfaction, but they can be assisted by channelling and maintaining initiatives to raise awareness of the needs of these patients.

Using a 3D handheld scanner to capture trochlear groove shape: proof of concept study

INTRODUCTION

Trochleoplasty is a surgical procedure used to treat patellar instability by modifying the trochlear groove. Analysis of the groove with a handheld scanner would enable accurate real-time planning and facilitate tailormade correction. We aimed to measure trochlear depth, sulcus angle, trochlear facet ratio, trochlear angle and lateral trochlear inclination angle and to establish inter- and intra-rater reliability for knee models to determine reliability and repeatability.

METHODS

The trochlear grooves of three knee models were scanned by two investigators. Three-dimensional reference models were created and surface-matched. Custom software was used to determine the desired parameters. The intraclass correlation coefficient (ICC) was used to determine test-retest reliability and the parameter results for each model that showed best reproducibility.

RESULTS

There was good interobserver reliability (trochlear depth, 1.0mm; sulcus angle, 2.7°; trochlear angle, 4.0°; lateral trochlear inclination angle, 4.0°), except in the trochlear facet ratio (32.0%) of one knee model. With outliers removed, the ICC was moderate to excellent in 73.34% of measurements, with trochlear depth showing the best reproducibility.

DISCUSSION

This feasibility study showed a handheld scanner in conjunction with supporting software can measure trochlear parameters with good to excellent inter- and intra-observer reliability.

Navigating marginalization and invisibility as Asian Americans in the U.S

In this paper, we articulate a conceptual model for the process of ethnic identity development and integration among Asian American children and youth that offers potential explanations for their marginalization as they negotiate multiple facets of their identities and locate themselves in local and national contexts. The conceptual model is based on an integration of theory and empirical research on the intertwined processes of ethnic identity development and socialization of children and youth in Asian American families and is anchored in the developmental domain of identity formation and integration. We present the conceptual model as three overlapping circles to represent salient features of physical and social contexts, prevalent metanarratives that have been empirically established as salient meaning-making frames pertinent to the lived experience of Asian Americans in the United States, and the dynamic individual-context interplay and mutual adjustment that is part of developmental process. We then build on the work of scholars who have advanced the theoretical and empirical literature on the Asian American experience in the United States, to illustrate how the three components (features of context, master narratives, and developmental processes) intersect in the overlapping spaces of the model to foreground the dialectic processes whereby identity is constructed as contextualized in place. The primary contribution of the model is to facilitate generating research questions that can unravel the complexities of how specific ethnic backgrounds (e.g., immigration and settlement histories), developmental status, individual position on societal racial/ethnic hierarchy, and prevalent societal metanarratives contextualize the development of an Asian American ethnic-racial identity. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

199 Use of A 3D Hand-Held Scanner to Capture Trochlear Groove Shape, A Proof-of-Concept Study

Introduction

Trochleoplasty is a surgical procedure used to treat patellar instability through modifying the trochlear groove. Analysis of the groove with a hand-held scanner would enable accurate real time planning and facilitate tailor made correction. We aimed to measure trochlear depth, sulcus angle, trochlear facet ratio, trochlear angle and lateral trochlear inclination angle and establish inter- and intra-rater reliability for each knee model.

Method

The trochlear groove of the knee models was scanned by two investigators and 3D reference models created. These were surface matched and custom software along with Excel was utilised to determine the desired parameters. Intraclass correlation coefficient (ICC) was used for test-retest reliability and to determine which parameter results, for each model, showed the best reproducibility.

Results

There was good inter-observer reliability - trochlear depth (1.0 mm), sulcus angle (2.7°), trochlear angle (4.0°) and lateral trochlear inclination angle (4.0°), except in the trochlear facet ratio (32.0%) of one knee model. With outliers removed ICC was good-excellent in (46.7%) of measurements, with trochlear depth showing the best reproducibility.

Conclusions

This feasibility study showed that the hand-held scanner in conjunction with supporting software can measure trochlear parameters in a controlled environment and justifies extending research into its use in trochleoplasty.

Taking Stock and Moving Forward: Research on Asian American Child Development

With this Special Section, the Asian Caucus of the Society for Research in Child Development seeks to promote a more inclusive, expanded, and holistic developmental science that can account for the diversity of developmental trajectories among Asian Americans. The articles elucidate, in turn, historical, conceptual, and methodological issues in studying Asian American child development. Although the articles foreground Asian Americans, the ideas should help advance theoretical and empirical work for other racial and ethnic groups, thereby contributing to a more valid understanding of child development.

An Integrated Conceptual Framework for the Development of Asian American Children and Youth

The diversity of circumstances and developmental outcomes among Asian American children and youth poses a challenge for scholars interested in Asian American child development. This article addresses the challenge by offering an integrated conceptual framework based on three broad questions: (a) What are theory-predicated specifications of contexts that are pertinent for the development of Asian American children? (b) What are the domains of development and socialization that are particularly relevant? (c) How can culture as meaning-making processes be integrated in conceptualizations of development? The heuristic value of the conceptual model is illustrated by research on Asian American children and youth that examines the interconnected nature of specific features of context, pertinent aspects of development, and interpretive processes.

When ‘el intérprete’ is also the ‘learner’: An Innovative Youth Empowerment Project for Immigrant Youth

In this paper, we present a Community Based Participatory Research (CBPR) project that documented an innovative youth empowerment program at a community based organization. The program at the core of this paper is aimed at strengthening cultural brokering, empowerment, civic engagement, and leadership skills by engaging youth as bilingual interpreters at community events to facilitate the participation of adults with limited English proficiency. Through the research-practice integration reflected in our study, we highlight how immigrant youth, engaged in activities that facilitate reflective thinking about their roles as cultural brokers, can be powerfully supported in navigating across their multiple cultural worlds.

Rapid Repeat Birth: Intersections Between Meaning-Making and Situational Support Among Multiparous Adolescent Mothers

This study examined interpretations of motherhood among adolescents who have experienced rapid repeat births (second births within 24 months of the primiparous birth). Analyses of participants’ descriptions of their transitions to motherhood indicate four modal narratives that vary along two axes: the adoption of a motherhood identity, and the nature (or stability) of relational support available. By using subjective perceptions of motivation, stability, and feelings of competence, this study linked intrapersonal meaning-making with situational sources of support to describe various pathways through repeat adolescent childbearing in a way that both confirms and enriches extant literature. The implications of this study instruct home visiting programs and other interventions designed to forestall repeat pregnancies by elucidating pathways of reinforcement or increased risk inherent in some maternal trajectories. Following this logic, interventions directed at improving outcomes for young mothers and their children would do well to consider the interplay between internal meaning-making, relational support, and the transformative power of adopting the mother identity.

Young Children's Responses to Unfamiliar Infants: The Effects of Adult Involvement

Pairs of unacquainted preschool children and 6 to 8 month old infants were observed individually for 10 minutes in a laboratory playroom as the infants' mother attempted to engage the child in interaction with her baby. There were approximately equal numbers of male and female children in two age groupings-2 to 3 years and 4 to 5 years old. Children stayed closer to the infant} engaged in more toy play with the infant, asked the mother more questions about the infant, and were less resistant to interact with the infant than were children in a previous study in which the mothers did not attempt to facilitate interaction. A larger number of children interacted with infants when mothers were involved rather than uninvolved. ANOVAs for age, sex, and sex composition of the child-infant pair revealed few significant effects suggesting that most preschool children can be encouraged to respond positively to babies after only a brief exposure.

Response to Commentaries on Taking Stock and Moving Forward: Research on Asian American Child Development

We briefly respond here to the commentaries to the Special Section focused on Asian American child development by Cheah, Lee, Beaupre, and Zhou, and McLoyd. We consider three questions raised in their comments. What does it mean to focus on Asian Americans? How should we examine development across the life course? How can we generate more policy- and practice-relevant research?.

Cultural variations in the play of toddlers

The present study examines differences in the social play of toddlers from four communities. Fourteen children, between the ages of 12 and 24 months, from four cultural communities (San Pedro, Guatemala; Kecioren, Turkey; Dhol-Ki-Patti, India; Salt Lake City, United States) participated in the study. This paper is based on an analysis of data from a larger study, which was designed to examine guided participation between caregivers and toddlers during daily routine activities (Rogoff, Mistry, Göncü, & Mosier, 1993). This study specifically examines episodes of social play which occurred during various activities. We addressed community differences in the occurrence, frequency, partners, and dynamics of social play. We also examined whether or not the kinds (i.e. pretend, object, physical, language, and games) and themes of children’s play varied as a function of the activity (i.e. exploring novel objects, dressing, free activity, and adult conversation) in which the play activities were embedded. The results indicated that social play occurred in each of the four communities, although the frequency and partners of social play presented cultural variations. Also, there were cultural variations in the numbers of children who engaged in the various kinds of play examined. Based on our results we conclude that developmental play theory should be extended to take into account cultural variation.

Improving Adolescent Parenting: Results From a Randomized Controlled Trial of a Home Visiting Program for Young Families

OBJECTIVES

Our aim was to estimate the effects of Healthy Families Massachusetts, a statewide home visiting program serving first-time adolescent parents, on parenting, child development, educational attainment, family planning, and maternal health and well-being.

METHODS

We used a randomized controlled trial design to randomly assign the 704 participants to a group receiving home visiting services or a control group. Between 2008 and 2012, telephone and in-person interviews were conducted and administrative data obtained at 12 and 24 months after enrollment. Intention-to-treat analyses compared group differences across 5 outcome domains: parenting, child health and development, educational and economic achievement, family planning, and parental health and well-being.

RESULTS

The home visiting program had a positive influence on parenting stress, college attendance, condom use, intimate partner violence, and engagement in risky behaviors. No negative findings were observed.

CONCLUSIONS

A paraprofessional home visiting program specifically targeting young mothers appears effective in domains of particular salience to young parents and their infants and toddlers. Expanding participation in the program appears a worthy goal for program administrators and policymakers.

Integration of culture and biology in human development

The challenge of integrating biology and culture is addressed in this chapter by emphasizing human development as involving mutually constitutive, embodied, and epigenetic processes. Heuristically rich constructs extrapolated from cultural psychology and developmental science, such as embodiment, action, and activity, are presented as promising approaches to the integration of cultural and biology in human development. These theoretical notions are applied to frame the nascent field of cultural neuroscience as representing this integration of culture and biology. Current empirical research in cultural neuroscience is then synthesized to illustrate emerging trends in this body of literature that examine the integration of biology and culture.

Early Childbearing and Educational Attainment Among Mainland Puerto Rican Teens

We report the results of a study about how early childbearing affected the educational trajectories of nine Puerto Rican teenage mothers living in New England. Raised largely on the mainland, participants chose to carry pregnancies to term and to participate in a parenting program for young mothers. Upon examination of shared meaning-making around childbearing, we found that, consistently, childbearing activated a family building script as the main task of motherhood. The pursuit of education as a developmental script was less consistent. We identified three approaches to reconciling the competing tasks of family building and educational attainment. “Successful jugglers” managed to do both, and even work at the same time. “Prioritizers” chose motherhood over education, either before or after childbearing. The two participants who did not follow a clear trajectory also happened to be the youngest in the study. Key factors contributing to each trajectory are presented.

The genome of the simian and human malaria parasite Plasmodium knowlesi

Plasmodium knowlesi is an intracellular malaria parasite whose natural vertebrate host is Macaca fascicularis (the 'kra' monkey); however, it is now increasingly recognized as a significant cause of human malaria, particularly in southeast Asia. Plasmodium knowlesi was the first malaria parasite species in which antigenic variation was demonstrated, and it has a close phylogenetic relationship to Plasmodium vivax, the second most important species of human malaria parasite (reviewed in ref. 4). Despite their relatedness, there are important phenotypic differences between them, such as host blood cell preference, absence of a dormant liver stage or 'hypnozoite' in P. knowlesi, and length of the asexual cycle (reviewed in ref. 4). Here we present an analysis of the P. knowlesi (H strain, Pk1(A+) clone) nuclear genome sequence. This is the first monkey malaria parasite genome to be described, and it provides an opportunity for comparison with the recently completed P. vivax genome and other sequenced Plasmodium genomes. In contrast to other Plasmodium genomes, putative variant antigen families are dispersed throughout the genome and are associated with intrachromosomal telomere repeats. One of these families, the KIRs, contains sequences that collectively match over one-half of the host CD99 extracellular domain, which may represent an unusual form of molecular mimicry.

Clinical and laboratory evaluation of a new specific ELISA for intact proinsulin

Intact proinsulin is a marker for pancreatic beta-islet cell secretion status, and elevated levels indicate insulin resistance of type 2 diabetic patients with a high diagnostic specificity. Determination of intact proinsulin in fasting morning plasma samples can be used to establish and/or identify the optimal anti-diabetic treatment as well as to monitor a potential protective treatment effect on beta-islet cell dysfunction. For widespread use as a routine marker, simple and reliable assays must become available for measurement in clinical laboratories. This study was performed to evaluate a new ELISA method specific for intact proinsulin determination compared with a commercial chemiluminescence test. Intra-assay imprecision was determined to be 2.4 - 5.5% (inter-assay: 3.2 - 4.3%). A sample cohort derived from non-diabetic healthy subjects (66 female, 29 male, age (median, range): 37 (19-77) years) was used to calculate a reference range for non-diabetic individuals of 1.8 - 11.0 pmol/l. The comparison of samples obtained from 7 diabetic patients (2 female, 5 male, age: 66 (44-72) years) from oral glucose tolerance tests resulted in an excellent correlation between the ELISA and the chemiluminescence assay (r = 0.989; p<0.001). A sample stability investigation with different sample specimens revealed that intact proinsulin is stable for two days at room temperature in EDTA whole blood and heparin whole blood tubes without centrifugation, while serum samples should be centrifuged immediately and frozen to retain intact proinsulin concentrations. As EDTA whole blood is the routine sample specimen for determination of HbA1c, a marker frequently measured in diabetic patients, this finding underlines the practicability of analyzing intact proinsulin from the same blood specimen. In conclusion our study revealed that the new ELISA shows excellent agreement with the commonly used chemiluminescence immunoassay. The ELISA can easily be introduced into routine laboratories and does not require any further specific instrumentation. Our additional finding that intact proinsulin is stable in EDTA whole blood samples, which can be obtained from the routine.sample for HbA1c measurement, is increasing the probability of the acceptance of this marker for routine assessment of beta-cell dysfunction and insulin resistance in type 2 diabetes.

A new enzyme-linked immunosorbant assay for the measurement of human vitamin D receptor

The hormonal actions of 1alpha,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] are mediated by its cognate receptor protein, the vitamin D receptor (VDR). Despite the growing importance of the VDR system as a modulator of cell growth and differentiation, convenient assays for quantitative measurement of VDR are not readily available, and [(3)H]1,25(OH)(2)D(3) ligand binding assays remain the standard method. In this paper, we present data to validate and characterize the usefulness of a new VDR enzyme-linked immunosorbant assay (ELISA) kit developed for the measurement of VDR in biological samples. In this assay, samples are added to microtitration wells coated with anti-VDR antibody and incubated with a second anti-VDR antibody that is biotinylated. The antibody receptor complex is then detected with streptavidin-labeled horseradish peroxidase followed by incubation with a chromogenic substrate, tetramethylbenzidine. The assay was found to be sensitive and accurate for measurements of VDR and compared favorably with the conventional radioligand binding assay (RBA). The interassay variation ranged from 5% to 25% and the intraassay variation was less than 5%. The ELISA presents several advantages over existing methodology, including the use of nonradioactive detection systems, lower protein and sample volume requirements, as well as convenience and speed. The assay can be completed in as short a time as 3 h, avoiding overnight incubations. Data are also presented to demonstrate the ability of the ELISA to detect both occupied and unoccupied VDR, making it a valuable research tool in settings where 1,25(OH)(2)D(3) is present. However, the ELISA, as currently formulated, is only useful for the detection of human VDR.

Insulin-like growth factor I (IGF-I) and IGF-binding protein-3 in benign prostatic hyperplasia and prostate cancer

In view of evidence indicating significant involvement of the insulin-like growth factor (IGF) system in the pathogenesis of prostate cancer, we measured serum IGF-I and IGF-binding protein-3 (IGFBP-3) in men with benign prostatic hyperplasia (BPH; n = 75) or prostatic carcinoma (CaP; n = 84). The age-matched patient populations were selected to have circulating prostate-specific antigen (PSA), the most reliable predictor of CaP, in the overlapping diagnostic gray zone range of approximately 4--10 microg/L. Of particular interest was investigation of intact, fragment, and total IGFBP-3 levels in relation to PSA, which is also a well established IGFBP-3 protease. Among the key findings were significantly higher IGF-I and intact IGFBP-3 levels in CaP vs. BPH (P < 0.001), whereas changes in fragment and total IGFBP-3 were statistically insignificant. As expected, total PSA levels were similar in the two groups of patients (P = 0.173), whereas free PSA levels were significantly lower in those with CaP (P < 0.001). IGF-I and IGFBP-3 (intact and total) correlated significantly (P = 0.024 to <0.001) and inversely (r = -0.26 to -0.35) with free PSA in BPH, but not in CaP, and no correlations were found in comparisons involving total PSA. Statistical analysis of the various markers and their combinations indicated enhanced performance of IGF-I/free PSA [receiver operating characteristics area under the curve (AUC) = 0.728] and intact IGFBP-3/free PSA (AUC = 0.737) ratios in discriminating between BPH and CaP compared with the currently used free/total PSA ratio (AUC = 0.689). Multivariate logistic regression models confirmed the observed relationships and identified IGF-I/free PSA and intact IGFBP-3/free PSA as independent factors in predicting the presence of CaP. We conclude that increases in IGF-I and intact IGFBP-3 levels are positively associated with the presence of CaP in this group of patients with low to moderately elevated PSA, and that their measurements in relation to PSA may help improve diagnostic discrimination between BPH and prostate cancer.

Immunoassay of insulin-like growth factor-binding protein-3 (IGFBP-3): new means to quantifying IGFBP-3 proteolysis

Posttranslational modifications, particularly proteolysis, may play a significant role in the regulation of insulin-like growth factor (IGF)-binding protein-3 (IGFBP-3) physiology, and thus, measurement of modified variants of IGFBP-3 and/or their combination ratios may have important research and diagnostic relevance. Based on evaluation of a panel of monoclonal and polyclonal IGFBP-3 antibodies, we constructed three new enzyme-linked immunosorbent assays (ELISAs) using a common capture and polyclonal (ELISA-3) or monoclonal (ELISA-1 and -2) detection antibodies and evaluated them in a two-step colorimetric procedure. Evaluation of ELISA-1-3 demonstrated detection limit, dynamic range, overall precision, and recovery of the added IGFBP-3 to be generally less than 0.04 microg/L, 2-100 microg/L, less than 10%, and 91-113%, respectively. IGF-I and -II, and IGFBP-1, -2, -4, -5, and -6 did not interfere. In normal adult sera (n = 26), seminal plasma (n = 14), pregnancy sera (n = 30), and amniotic fluid (n = 30), ELISA-1-3 detected significantly different IGFBP-3 levels (by up to 6-fold, on the average), whereas levels in seminal plasma determined by ELISA-1 were undetectable. Comparison of the values obtained vs. corresponding levels by an established method (Diagnostic Systems Laboratories, Inc., active IGFBP-3 ELISA) were similarly sample dependent and, on the average, varied by up to 19-fold. Only ELISA-3 compared well with the Diagnostic Systems Laboratories, Inc., IGFBP-3 ELISA when samples from normal adults were analyzed. The observed variability could not be totally explained by 50% lower reactivity of ELISA-1-3 for glycosylated IGFBP-3 vs. the nonglycosylated form, and changes in phosphorylation had no effect on immunoreactivity. Evaluation of IGFBP-3 after proteolysis by seminal plasma, plasmin, or thrombin suggested recognition of intact IGFBP-3 by ELISA-1, whereas ELISA-3 appeared to measure intact and proteolyzed IGFBP-3 (total IGFBP-3) with similar potency. In contrast, levels determined by ELISA-2 increased severalfold, indicating preferential recognition of IGFBP-3 fragments. We propose that immunoassay capable of differential determination of IGFBP-3 variants may help better define the physiological importance and potential clinical value of IGFBP-3 measurements.

Preparation of recombinant bovine, porcine, and porcine W4R/R5K leptins and comparison of their activity and immunoreactivity with ovine, chicken, and human leptins

Recombinant ovine Ala-leptin (GenBank Accession No. U84247, of ovine leptin), previously prepared in our laboratory in prokaryotic expression plasmid pMON3401, was mutated using a mutagenesis kit to prepare plasmids encoding for bovine (GenBank Accession No. U50365) and porcine (GenBank Accession No. U59894) leptins and for porcine leptin analogue W4R/R5K. Escherichia coli cells transformed with these plasmids overexpressed large amounts of these proteins upon induction with nalidixic acid. The expressed proteins, found in inclusion bodies, were refolded and purified to homogeneity using subsequently anion- and cation-exchange chromatography. All three purified proteins showed a single band of the expected molecular mass of 16 kDa in SDS-PAGE in the presence of reducing agent and were composed of 90-100% monomers. Proper refolding was evidenced by comparing their CD spectra to those of previously prepared chicken and ovine leptins and to commercially available human leptin. The amino acid content of the purified proteins closely resembled the predicted composition. The biological activity of bovine leptin, porcine leptin, and porcine leptin analogue W4R/R5K was evidenced by their ability to stimulate proliferation of leptin-sensitive BAF/3 cells transfected with a long form of human leptin receptor. All three proteins, as well as ovine and chicken leptins, but not human leptin, exhibited a very high degree of cross-immunoreactivity against antiserum raised against ovine leptin in rabbits. In contrast, none or very low cross-immunoreactivity was observed against antiserum raised against ovine leptin in goats.

Measurement of the acid-labile subunit of the insulin-like growth factor binding protein complex in human serum: a comparison of four immunoassays

The acid-labile subunit (ALS) of the high molecular weight insulin-like growth factor binding protein complex is a liver-derived glycoprotein which is regulated by growth hormone and serves as a serum marker of growth hormone action. We have compared the measurement of ALS by four immunoassay methods (two RIAs, two ELISAs) utilizing various polyclonal and monoclonal antibodies raised against natural or recombinant human ALS, or synthetic ALS peptides. Despite the variety of methodologies and reagents, results obtained by the four methods were highly correlated for 125 sera from various patient groups, and when compared for individual groups of sera from healthy children and adults, growth hormone-deficient children and adults, and subjects with acromegaly. Some weaker correlations among methods were seen when measuring ALS levels in groups of sera from pregnant subjects and subjects with chronic renal failure. An assay using antibodies raised against recombinant ALS yielded lower apparent values than the other methods in patient sera, the discrepancy probably being attributable to a difference in standardization. We conclude that a variety of assay formats and reagents can yield serum ALS values of potential clinical utility.

Selective inhibition of low affinity IgE receptor (CD23) processing: P1' bicyclomethyl substituents

Using a variety of alpha-hydroxy hydroxamic acid derivatives, the size and shape of the S1' pocket for the CD23 processing metalloprotease has been explored. It has been demonstrated that a P1' 2-naphthylmethyl group occupies most of the available space and gives excellent selectivity against fibroblast collagenase (matrix metalloproteinase-1, MMP-1) and other MMPs.

The high molecular weight insulin-like growth factor-binding protein complex: epitope mapping, immunoassay, and preliminary clinical evaluation

Measurements of insulin-like growth factor I(IGF-I), IGF-binding protein-3 (IGFBP-3), and the acid-labile subunit (ALS) are important in assessing the GH-IGF axis. As nearly all IGF-I, IGFBP-3, and ALS circulate in a GH-dependent ternary protein complex, direct determination of the complex may be of significant analytical and clinical importance. We evaluated a panel of monoclonal antibodies (mAb) to human IGFBP-3 and classified them into four groups (G-1 to G-4). G-1 antibodies recognized epitopes that mapped at or near IGFBP-3 ligand (IGF)-binding site. This region overlapped with the G-2 defined region, which, in turn, overlapped with G-3 epitopes defined by one antibody (mAb 3). Only G-1 and G-3 antibodies paired without interference. mAb 9 recognized a conformational epitope (G-4), and mAb 10 was nonreactive. In pairwise mixed antibody evaluation, mAbs in G-2 and G-3 showed simultaneous binding to serum IGFBP-3 complexes in combination with an anti-IGF-I or an anti-ALS antibody. On this basis, two novel enzyme-linked immunosorbent assays (ELISAs) involving IGFBP-3/IGF-I (ELISA-1) and IGFBP-3/ALS (ELISA-2) recognition partners were developed, both demonstrating acceptable analytical performance characteristics. IGFBP-3 complexes measured by ELISA-1 and -2 in samples from normal individuals and subjects with GH deficiency, acromegaly, and GH receptor deficiency more tightly correlated with IGF-I, IGFBP-3, and ALS than IGF-II. ELISA-1 determinations were comparatively more age dependent and, in comparison to ELISA-2, showed better discriminations among the various sample groups, particularly among GH receptor deficiency, normal, and GH deficiency subjects. The development of IGFBP-3 complex ELISAs may simplify diagnostic applications and facilitate investigations of the physiological relevance of the ternary complex formation.

Plasma levels of insulin-like growth factor-I and lung cancer risk: a case-control analysis

BACKGROUND

Insulin-like growth factors (IGFs), in particular IGF-I and IGF-II, strongly stimulate the proliferation of a variety of cancer cells, including those from lung cancer. To examine the possible causal role of IGFs in lung cancer development, we compared plasma levels of IGF-I, IGF-II, and an IGF-binding protein (IGFBP-3) in patients with newly diagnosed lung cancer and in control subjects.

METHODS

From an ongoing hospital-based, case-control study, we selected 204 consecutive patients with histologically confirmed, primary lung cancer and 218 control subjects who were matched to the case patients by age, sex, race, and smoking status. IGF-I, IGF-II, and IGFBP-3 plasma levels were measured by enzyme-linked immunosorbent assay and then divided into quartiles, based on their distribution in the control subjects. Associations between the IGF variables and lung cancer risk were estimated by use of odds ratios (ORs). Reported P values are two-sided.

RESULTS

IGF and IGFBP-3 levels were positively correlated (all r>.27; all P<.001). High plasma levels of IGF-I were associated with an increased risk of lung cancer (OR = 2.06; 95% confidence interval [CI] = 1.19-3.56; P = .01), and this association was dose dependent in both univariate and multivariate analyses. Plasma IGFBP-3 showed no association with lung cancer risk unless adjusted for IGF-I level; when both of these variables were analyzed together, high plasma levels of IGFBP-3 were associated with reduced risk of lung cancer (OR = 0.48; 95% CI = 0.25-0.92; P = .03). IGF-II was not associated with lung cancer risk.

CONCLUSIONS

Plasma levels of IGF-I are higher and plasma levels of IGFBP-3 are lower in patients with lung cancer than in control subjects. If these findings can be confirmed in prospective studies, measuring levels of IGF-I and IGFBP-3 in blood may prove useful in assessing lung cancer risk.

Insulin-like growth factors (IGF-I, free IGF-I and IGF-II) and insulin-like growth factor binding proteins (IGFBP-2, IGFBP-3, IGFBP-6, and ALS) in blood circulation

Insulin-like growth factors (IGFs) and IGF binding proteins (IGFBPs) play an important role in cell growth and differentiation. Clinical and epidemiological studies have indicated that measuring IGFs and IGFBPs in blood has potential implications in assessing growth-related abnormalities and risks of certain types of cancer. To facilitate the application, we reported a large collection of reference ranges of IGFs and IGFBPs in normal population and evaluations of these molecules in serum and plasma as well as the impact of freeze-thaw cycles on the measurement. IGF-I, IGFBP-3 andALS showed a similar pattern of change associated with age. Levels of these molecules were low at birth and increased with age through puberty. After puberty the levels declined slowly with age. Overall, IGF-I, IGFBP-3 and ALS were slightly higher in females than in males. Free IGF-I accounted for about 1% of the total IGF-I and its variation with age was similar to total IGF-I. IGF-II levels were also increased with age from birth to puberty, but became stable after puberty. There was little difference in IGF-II levels between genders. IGFBP-2 levels declined with age from birth to puberty. Levels of IGFBP-6 in contrast were increased with age. These IGF binding proteins were higher in males than in females. IGFs, IGFBP-3 and ALS were 5-10% higher in serum than in plasma. IGFBP-2 and IGFBP-6 differed substantially between serum and plasma. Freeze-thaw treatment up to five cycles had little impact on plasma levels of IGFs and IGFBP-3. Our observations suggest that levels of IGFs and their binding proteins are varied with age, gender, and types of specimen and that these variations need to be taken into consideration when IGFs and their binding proteins are utilized in clinic and research.

The acid-labile subunit of human ternary insulin-like growth factor binding protein complex in serum: hepatosplanchnic release, diurnal variation, circulating concentrations in healthy subjects, and diagnostic use in patients with growth hormone deficiency

Circulating insulin-like growth factor-I (IGF-I) is predominantly bound in the trimeric complex comprised of IGF binding protein-3 (IGFBP-3) and acid-labile subunit (ALS). Circulating concentrations of IGF-I, IGFBP-3 and ALS are believed to reflect the GH secretory status, but the clinical use of ALS determination is not known. We therefore, determined the: 1) hepatosplanchnic release of ALS by liver vein catheterization (n=30); 2) 24-h diurnal variation of ALS (n=8); 3) normal age-related ranges of circulating ALS (n=1158); 4) diagnostic value of ALS in 108 patients with childhood-onset GH deficiency (GHD). We found: 1) no significant arteriovenous gradient over the liver ofALS, IGF-I, and IGFBP-3; 2) the diurnal variation of ALS was 12% (mean coefficient of variation percent); 3) ALS levels increased throughout childhood with maximal levels in puberty, with a subsequent decrease with age in adults; and 4) ALS levels were below -2 SD in 57 of 79 GHD patients (sensitivity 72%) and above 2 SD in 22 of 29 patients with normal GH response (specificity 76%), which was similar, compared with the diagnostic utility of IGF-I and IGFBP-3. Finally, our findings indicate that hepatic ALS production is not measurable by this approach or, alternatively, that the liver is not the primary source of circulating ALS, IGF-I, or IGFBP-3 in humans. In conclusion, we have provided extensive normal data for a novel ALS assay and found that circulating ALS levels exhibit minor diurnal variation. We suggest that ALS determination may be used in future classification of adults suspected of GHD.

Filter paper blood spot assay of human insulin-like growth factor I (IGF-I) and IGF-binding protein-3 and preliminary application in the evaluation of growth hormone status

To facilitate broader applications of insulin-like growth factor I (IGF-I) and IGF-binding protein-3 (IGFBP-3) analysis, we developed procedures for their measurements in extracts of whole blood dried on filter paper. A single 8-mm diameter filter paper disc containing about 13 microL blood was used. IGFBP-3 was efficiently extracted in a buffer within 1 h of incubation. IGF-I extraction involved incubation in buffer followed by acidification and neutralization steps. Blood spot assays showed intra- and interassay coefficients of variation (including interspot variations) of 5.4-16.7% for IGF-I and 6.6-11.7% for IGFBP-3; recoveries were 97 +/- 7.1% and 101 +/- 8.7%, respectively. Recoveries of IGF-I and IGFBP-3 in response to 4- to 8-fold variations in extraction buffer volume were 97 +/- 8.2% and 107 +/- 6.1%, respectively. Dried blood spot IGF-I and IGFBP-3 showed greater than 1-month stability at -20 C, 4 C, and room temperature and retained more than 65% of the immunoreactivity after approximately 1 month at 37 C. Both IGF-I and IGFBP-3 were contained within the plasma fraction of whole blood, and variations (mean +/- SD) in IGF-I (204 +/- 29 micrograms/L) and IGFBP-3 (4.4 +/- 0.48 mg/L) measured in extracts of dried blood spot with adjusted hematocrit of 0.2-0.62 were acceptable. IGF-I and IGFBP-3 in paired plasma and dried blood spot extracts of random samples (n = 46) showed excellent correlation (r > 0.94) with slopes of near unity. Compared to conventional methods, the filter paper procedures were equally effective in distinguishing IGF-I and IGFBP-3 levels in untreated GH receptor-deficient (n = 11) and age-matched normal controls (n = 16). We conclude that blood collected on filter paper is ideal for IGF-I and IGFBP-3 analysis and may find applications in pediatric and large scale infant screening programs.

Acid-labile subunit of human insulin-like growth factor-binding protein complex: measurement, molecular, and clinical evaluation

Although the acid-labile subunit (ALS) of the approximately 150-kDa insulin-like growth factor (IGF)-binding protein (IGFBP) complex was described over a decade ago, details of ALS physiology have remained largely uncertain. We evaluated antibodies to synthetic human ALS and constructed a noncompetitive ALS enzyme-linked immunosorbent assay. Whereas uncomplexed ALS is directly measured, determination of total levels required sample pretreatment with SDS, which was found to optimally dissociate complexed ALS and significantly enhance ALS immunoreactivity. ALS in random adult sera was approximately 50% uncomplexed, and samples devoid of complexed ALS by immunoaffinity separation contained about 54% of the total levels. Serum ALS fractionated by gel filtration high performance liquid chromatography eluted in a single peak at approximately 150 kDa with IGF-I and IGFBP-3, but appeared at about 400-500 kDa after sample acidification and fractionation under acidic condition. The unexpected shift in ALS immunoreactivity remained unchanged when acid-neutralized or SDS-treated samples were fractionated under neutral pH and was reproducible when the 150-kDa complex was isolated, treated with acid or SDS, and rechromatographed. ALS in adult sera more tightly correlated with IGFBP-3 than IGF-I or IGF-II. The total levels (mean +/- SD) were 16.7 +/- 3.7 mg/L in 22 normal subjects, 28.3 +/- 8.1 mg/L in 20 acromegalic patients, and 9.5 +/- 3.8 in 32 GH-deficient adults. Little or no ALS was detectable in amniotic fluid, cerebrospinal fluid, seminal plasma, or milk, whereas high levels were present in synovial fluid. The development of ALS enzyme-linked immunosorbent assay should greatly facilitate further investigations of this unique glycoprotein.