Next-Generation Models for Predicting Winning Times in Elite Swimming Events: Updated Predictions for the Paris 2024 Olympic Games

PURPOSE

To evaluate statistical models developed for predicting medal-winning performances for international swimming events and generate updated performance predictions for the Paris 2024 Olympic Games.

METHODS

The performance of 2 statistical models developed for predicting international swimming performances was evaluated. The first model employed linear regression and forecasting to examine performance trends among medal winners, finalists, and semifinalists over an 8-year period. A machine-learning algorithm was used to generate time predictions for each individual event for the Paris 2024 Olympic Games. The second model was a Bayesian framework and comprised an autoregressive term (the previous winning time), moving average (past 3 events), and covariates for stroke, gender, distance, and type of event (World Championships vs Olympic Games). To examine the accuracy of the predictions from both models, the mean absolute error was determined between the predicted times for the Budapest 2022 World Championships and the actual results from said championships.

RESULTS

The mean absolute error for prediction of swimming performances was 0.80% for the linear-regression machine-learning model and 0.85% for the Bayesian model. The predicted times and actual times from the Budapest 2022 World Championships were highly correlated (r = .99 for both approaches).

CONCLUSIONS

These models, and associated predictions for swimming events at the Paris 2024 Olympic Games, provide an evidence-based performance framework for coaches, sport-science support staff, and athletes to develop and evaluate training plans, strategies, and tactics, as well as informing resource allocation to athletes, based on their potential for the Paris 2024 Olympic Games.

Protocol of trans-Tasman feasibility randomised controlled trial of the Younger Women's Wellness After Breast Cancer (YWWACP) lifestyle intervention

BACKGROUND

Younger women (defined as those < 50 years who are likely pre-menopausal at time of diagnosis) with breast cancer often experience persistent treatment-related side effects that adversely affect their physical and psychological wellbeing. The Women's Wellness After Cancer Program (WWACP) was adapted and piloted in Australia to address these outcomes in younger women. The aims of this feasibility study are to determine (1) the potential to translate the Younger WWACP (YWWACP) intervention to a broader population base in Aotearoa/New Zealand and Australia, and (2) the potential for success of a larger, international, phase ΙΙΙ, randomised controlled trial.

METHODS

This bi-national, randomised, single-blinded controlled trial involves two main study sites in Aotearoa/New Zealand (Kōwhai study) and Australia (EMERALD study). Young women aged 18 to 50 years who completed intensive treatment (surgery, chemotherapy, and/or radiotherapy) for breast cancer in the previous 24 months are eligible. The potential to translate the YWWACP to women in these two populations will be assessed according to several feasibility outcomes. These include examining intervention accessibility, acceptability and uptake; intervention sustainability and adherence; the prevalence components of the intervention in the control group; intervention efficacy; participants' perception of measurement burden; the effectiveness of planned recruitment strategies; and trial methods and procedures. The studies collectively aim to enrol 60 participants in the intervention group and 60 participants in the control group (total = 120 participants).

DISCUSSION

Ethical approval has been received from the Southern Health and Disability Ethics Committee (Kōwhai ref: 19/STH/215), and UnitingCare Human Research Ethics Committee (EMERALD ref: 202103). This study will provide important data on the feasibility of the refined YWWACP in the trans-Tasman context. This study will account for and harmonise cross-country differences to ensure the success of a proposed international grant application for a phase ΙΙΙ randomised controlled trial of this program to improve outcomes in younger women living with breast cancer.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry (ANZCTR): Kōwhai ACTRN12620000260921 , registered on 27 February 2020. EMERALD ACTRN12621000447853 , registered on 19 April 2021.

Determining patient knowledge of direct oral anticoagulants: a questionnaire study

Introduction

There has been a significant increase in the number of patients prescribed Direct Oral Anticoagulants (DOACs) (1). One of the advantages of DOACs is reduced need for monitoring compared to warfarin, however less frequent contact with healthcare professionals (HCPs) may contribute to poor patient knowledge leading to negative health consequences.

Aim

To determine patients’ knowledge on DOACs in the hospital and community pharmacy setting.

Methods

Participants were recruited from a university hospital and from a convenience sample of community pharmacies. Potential participants were identified by the pharmacist in that setting using the following criteria: age ≥18 years, adequate cognition, DOAC use ≥3 months. Following consent, the participant completed a questionnaire which consisted of participant demographics and questions from the KODOA (The Knowledge of Direct Oral Anticoagulants) questionnaire. Depending on participant preference, they either self-completed the questionnaire or provided oral answers which the researcher documented. Based on previous research (2), a target sample of 40 participants was set. Descriptive statistics were performed.

Results

40 participants were recruited; the mean (SD) age was 70.2 years (10.1), with 70% of participants reporting male gender. 62.5% of participants had an indication of atrial fibrillation. Mean (SD) duration of DOAC use was 5.6 years (3.6). Most patients rated their knowledge of their DOAC as moderate (50%) or good (27.5%). The results of the KODOA are presented in the table. The average score achieved by participant was 11.55/15 (± 1.88 SD). Participants scored high in areas such as DOAC indication, frequency of dosing, side-effects, drug interactions and when to seek further help. Areas of knowledge deficits included what to do when patients have forgotten a dose or have taken too much DOAC.

Conclusion

One limitation of the questionnaire is that the questions are presented in a multiple-choice format and it is possible that participants may have selected the correct answer due to chance. However, overall, participants demonstrated good levels of knowledge of their DOAC therapy. This study has identified areas of knowledge deficits which could be included in patient education when HCPs are counselling patients, when starting their DOAC and continually throughout treatment.

References

(1) Barry, Michael. Medicines Management Programme: Oral anticoagulants for stroke prevention in non-valvular atrial fibrillation [Internet]. 2019 [cited 2021 Jul 24]. Available from: https://www.hse.ie/eng/about/who/cspd/ncps/medicines-management/oral-anticoagulants/oral-anticoagulants-for-stroke-prevention-in-non-valvular-atrial-fibrillation-march-2019.pdf

(2) Metaxas C, Albert V, Stahl M, Hersberger KE, Arnet I. Development and validation of a questionnaire to self-assess patient knowledge of direct oral anticoagulants (KODOA-test). Drug Healthc Patient Saf. 2018 Jul 20;10:69–77.

The Effect of Exercise Training Intensity on VO2max in Healthy Adults: An Overview of Systematic Reviews and Meta-Analyses

This study aimed to evaluate systematic reviews and meta-analyses that have examined the effect of exercise training on VO2max in healthy individuals at different intensities. Five databases were searched: EBSCOhost, MEDLINE/PubMed, SPORTDiscus, Web of Science, and Google Scholar. Eligibility criteria for selecting reviews included systematic reviews and meta-analyses of healthy adults that examined the effect of lower intensity training (LIT) and/or high intensity training (HIT) on VO2max. Eleven reviews met the eligibility criteria. All reviews were of moderate-to-very strong methodological quality. The included reviews reported data from 179 primary studies with an average of 23 ± 10 studies per review. All reviews included in this overview showed that exercise training robustly increased VO2max at all intensities. Three meta-analyses that compared LIT versus HIT protocols on VO2max reported small/moderate beneficial effects for HIT over LIT; however, the beneficial effects of HIT on VO2max appear to be moderated by training variables other than intensity (e.g., training impulse, interval length, training volume, and duration) and participants' baseline characteristics (e.g., age and fitness levels). Overall, evidence from this overview suggests that the apparent differences between LIT and HIT protocols on VO2max were either small, trivial, or inconclusive, with several methodological considerations required to standardise research designs and draw definitive conclusions.

A190 EPIDEMIOLOGY OF MUSCULOSKELETAL MANIFESTATIONS IN PAEDIATRIC INFLAMMATORY BOWEL DISEASE: A SYSTEMATIC REVIEW

Background

Paediatric inflammatory bowel disease (p-IBD) is a chronic and relapsing gastrointestinal disorder of childhood with associated long-term morbidity. Several extraintestinal manifestations (EIMs) are described, the most common being joint pain and/or inflammation. In 1986, Passo et al. were the first to describe the association of arthritis in p-IBD patients. However, since then, data on the epidemiology, patient and disease factors associated with, treatments for, and outcomes of p-IBD associated musculoskeletal (MSK) disease are not well-established.

Aims

Our study aims to summarize the literature on the epidemiology of MSK EIMs in p-IBD in the era of biologics.

Methods

A systematic review of the literature was performed. PubMed, Embase, Cochrane Library, Web of Science Core Collection, and CINAHL databases were searched with relevant keywords. Studies in English published from January 1, 2000 to December 21, 2020 were included. In total, 3893 papers were identified and screening was performed by two independent reviewers (AA, MS). Conflicts were resolved by a third reviewer (EC, RB). Study and population characteristics were recorded. The primary outcomes of interest were MSK symptoms at presentation and their course, method of diagnosis and definitions used for MSK EIMs. Risk of bias assessment was performed using the JBI Critical Appraisal Tools.

Results

Thirteen studies were included for full review, which were primarily single-centre observational studies with retrospective or cross-sectional design. The method of diagnosis for MSK EIMs varied across the studies, with only 4 studies stating the involvement of a rheumatologist in diagnosis. The definitions also varied, with MSK EIMs such as peripheral arthritis, axial arthritis, enthesopathy, and arthralgia included. Only 7 studies focused on MSK EIMs as their primary outcome, while the remainder reported on all p-IBD associated EIMs. There was a wide range in the prevalence of MSK EIMs from 2–35% (Figure 1). Four studies reported on the therapeutic response of MSK EIMs, and only 3 of those reported on biologic use. Risk of bias demonstrated heterogeneity in the quality of included studies.

Conclusions

This is the first systematic review of the literature for MSK EIMs in p-IBD. Analysis was limited due to variability in study design and data-reporting methods. Included studies reported prevalence of MSK EIMs, but the ascertainment of MSK EIMs, both method and definition varied with a clear lack in standardization. Our study demonstrates the need for further research of the MSK associations of p-IBD and to explore optimal management to advance care for this group of children.

Funding Agencies

None

A42 HETEROGENEITY IN EFFICACY AND SAFETY ENDPOINTS FOR PEDIATRIC CLINICAL TRIALS IN INFLAMMATORY BOWEL DISEASE: A NEED FOR HARMONIZATION

NOT PUBLISHED AT AUTHOR’S REQUEST

Funding Agencies: None

P04 An evaluation of antimicrobial stewardship education in the School of Pharmacy of an Irish university—a mixed methods study

Background

Antimicrobial stewardship (AMS) is essential to control the emergence of antimicrobial resistance (AMR) which has become an international health priority. Education of undergraduate students on AMS and AMR is a strategic objective in the WHO Global Action Plan on AMR and Ireland's National Action Plan.^1,2 Research on AMS/AMR education has focused primarily on medical students with less emphasis on those from other healthcare profession including pharmacy students.

Objectives

To investigate AMS and AMR education in the Pharmacy undergraduate programme in the School of Pharmacy of an Irish University.

Methods

A mixed methods study was conducted. Ten semi-structured interviews were conducted in October 2019 with academic staff to capture their views on AMS education. Participants included staff members from different disciplines, those identified as involved in teaching elements of infectious disease, antibiotics, AMS and related topics, and those involved in curriculum design and approval within the School of Pharmacy. Interview transcripts were analysed by thematic analysis. An electronic survey of 17 questions was emailed to all second to fifth year UCC Pharmacy students in October 2019 to gather students’ views and experiences of AMS education. The survey contained four sections which addressed demographics, AMS, resources and education using open-ended, closed-ended or Likert-scale questions. Ethical approval was obtained.

Results

Six key themes were identified from the ten interviews: (i) curriculum priorities and capacity; (ii) housing of the subject, fragmentation and cohesion; (iii) integration; (iv) communication; (v) teaching methods; and (vi) assessment methods. 113 students participated in the survey (32.3% response rate). 96% agree that a strong knowledge of antimicrobials for their future careers is important, and over 89% of students desire more education on AMR and AMS. Only 43% of students found their AMS education provided sufficient preparation for practice. Students felt most prepared to recognize clinical signs of infection and least prepared for IV to oral switching, interpreting biological marker and de-escalation of antimicrobials. Over 50% of students never used or were not familiar with the national primary care antimicrobial guidelines: www.antibioticprescribing.ie.

Conclusions

Pharmacy students and staff agree that AMS and AMR are important and need enhanced educational focus. Students feel there are gaps in their AMS education and expressed a desire for more education in this area. Improved communication and identification of curriculum priorities by staff could help to establish a more cohesive and comprehensive educational approach to this area.

Behavioral and hypothalamic transcriptome analyses reveal sex-specific responses to phenanthrene exposure in the fathead minnow (Pimephales promelas)

Environmental concentrations of the polycyclic aromatic hydrocarbon phenanthrene can become elevated with petroleum processing, industrial activities, and urban run-off into waterbodies. However, mechanisms related to its neurotoxicity in fish are not fully described. Here, we exposed adult fathead minnows (FHM) to an average measured concentration of 202 μg phenanthrene/L over a 47-d period. Behaviors of male and female FHM were assessed using a novel aquarium test. Phenanthrene exposed females displayed equilibrium loss, while phenanthrene exposed males spent less time in the aquarium bottom, suggesting phenanthrene reduced anxiety-related behavior. To elucidate putative mechanisms underlying behaviors, we determined the hypothalamic transcriptome profile, a critical integration centre for the regulation of behaviors. There were 1075 hypothalamic transcripts differentially expressed between males and females (sex-specific) while 15 transcripts were phenanthrene-specific. Thus, sex of the animal was more pervasive at influencing the transcriptome compared to phenanthrene and this may partially explain the divergent behavioral responses between sexes. Transcripts altered by phenanthrene included palmitoylated 3 membrane protein, plectin 1,ATP synthase membrane subunit c, and mitochondrial ribosomal protein S11. Gene set enrichment analysis revealed less than 5% of the gene networks perturbed by phenanthrene were shared between males and females, thus phenanthrene altered the hypothalamic transcriptome in a sex-specific manner. Gene networks shared between both sexes and associated with phenanthrene-induced neurotoxicity included processes related to mitochondrial respiratory chain dysfunction, epinephrine/norepinephrine release, and glutamate biosynthesis pathways. Such energy deficits and neurotransmitter disruptions are hypothesized to lead to behavioral deficits in fish. This study provides mechanistic insights into phenanthrene-induced neurotoxicity and how it may relate to changes in fish behaviors.

Socio-ecological correlates of physical activity in a nationally representative sample of adolescents across Ireland and Northern Ireland

•

Adolescent physical activity (PA) can be categorized into different levels.

•

Categories include inactive, somewhat active, active, or daily active.

•

Demographic, intrapersonal and interpersonal factors varied by PA category.

•

Depending on PA category, school- and community-related factors also varied.

•

As Every Move Counts, future correlate analyses may benefit from PA categorization.

Physical activity (PA) is associated with a range of health benefits for adolescents. Few adolescents meet one hour daily of moderate-to-vigorous physical activity (MVPA). The World Health Organisation (WHO) now recommends an ‘on average’ accumulation. In light of these updates, comparing correlates associated with meeting versus not meeting the PA guidelines provides limited understanding of adolescent behavioural choices. The aim of this study was to fractionate PA behaviour and investigate influential socio-ecological correlates across a diverse range of PA categories. A nationally representative sample (N = 6,563; age = 13.5 ± 1.9 years; male = 46.2%) completed a researcher supervised self-report survey. Empirically established instruments assessing the socio-ecological correlates of PA were included. Levels of MPVA were categorised into daily active (60mins.MVPA.daily), active (60mins.MVPA.5–6 days), somewhat active (60mins.MVPA.3–4 days) or inactive (60mins.MVPA.0–2 days). Descriptive statistics, chi-square analyses and multivariate blockwise binary logistic regression models were run separately for each PA category. Few were daily active (12.7%), 33.6% active, 36.5% somewhat active and 17.2% were inactive. Results showed that correlates differed in terms of direction and strength, depending on individual activity status. Increasing age was positively associated with being somewhat active, but not with being active or daily active. Attending an ‘all-girls school’ was negatively associated with daily active. High interpersonal support from family, friends or teachers was negatively associated with inactive or somewhat active, reducing the likelihood of adolescents remaining in these unhealthy PA categories. This novel information is useful for exploring previously established inconsistent relationships with PA. More sensitive categorisation and intervention tailoring to diverse PA categories is required.

Evaluation of VIDAS® Listeria species Xpress (LSX) Immunoassay Method for the Detection of Listeria species in Foods: Collaborative Study

In a multilaboratory study, the effectiveness of an alternative method for rapid screening of Listeria species compared to traditional reference methods was demonstrated in a variety of food products. A collaborative study was conducted to compare the VIDAS® Listeria species Xpress (LSX) method and the standard cultural methods for the detection of Listeria species in foods. Six food types were tested: vanilla ice cream, cheddar cheese, raw ground beef, frozen green beans, deli turkey, and cooked shrimp. Each food, inoculated with a different Listeria strain at two levels and uninoculated test portions, was analyzed by each method. A total of 15 laboratories representing government and industry participated. In this study 1134 tests were analyzed in the statistical analysis. There were 490 positives by the VIDAS LSX method using the sample boiling step, 483 positives by the VIDAS LSX method using the Heat and Go system, and 439 positives by the standard culture methods. Overall, the Chi-square result for the VIDAS LSX method with boiling for all foods was 7.25, indicating a significant statistical difference between the VIDAS method and the standard methods at the 5% confidence. For the VIDAS LSX method with the Heat and Go system, the Chi-square result for all foods was 5.37, indicating a significant statistical difference between the VIDAS LSX assay with the Heat and Go system and the standard methods at the 5% level of significance. In both cases, the VIDAS method was more sensitive than the standard methods. The LSX method detects Listeria species in foods with negative or presumptive positive results in a minimum of 30 h compared to at least 5 days for the cultural methods. Based on the results of this collaborative study, it is recommended that the VIDAS LSX method be adopted as an AOAC Official MethodSM for the detection of Listeria species in dairy products, vegetables, seafood, raw meats and poultry, and processed meats and poultry.

The Impact of Resistance Training on Swimming Performance: A Systematic Review

BACKGROUND

The majority of propulsive forces in swimming are produced from the upper body, with strong correlations between upper body strength and sprint performance. There are significant gaps in the literature relating to the impact of resistance training on swimming performance, specifically the transfer to swimming performance.

OBJECTIVE

The aims of this systematic literature review are to (1) explore the transfer of resistance-training modalities to swimming performance, and (2) examine the effects of resistance training on technical aspects of swimming.

METHODS

Four online databases were searched with the following inclusion criteria: (1) journal articles with outcome measures related to swimming performance, and (2) competitive swimmers participating in a structured resistance-training programme. Exclusion criteria were (1) participants with a mean age <16 years; (2) untrained, novice, masters and paraplegic swimmers; (3) triathletes and waterpolo players; (4) swimmers with injuries or illness; and (5) studies of starts and turns specifically. Data were extracted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and the Physiotherapy Evidence Database (PEDro) scale was applied.

RESULTS

For optimal transfer, specific, low-volume, high-velocity/force resistance-training programmes are optimal. Stroke length is best achieved through resistance training with low repetitions at a high velocity/force. Resisted swims are the most appropriate training modality for improving stroke rate.

CONCLUSION

Future research is needed with respect to the effects of long-term resistance-training interventions on both technical parameters of swimming and overall swimming performance. The results of such work will be highly informative for the scientific community, coaches and athletes.

Dry-Land Resistance Training Practices of Elite Swimming Strength and Conditioning Coaches

Crowley, E, Harrison, AJ, and Lyons, M. Dry-land resistance training practices of elite swimming strength and conditioning coaches. J Strength Cond Res 32(9): 2592-2600, 2018-No research to date has investigated dry-land resistance (RT) training practices of elite swimming strength and conditioning coaches. This is the first comprehensive study exploring dry-land RT training practices in swimming. The aims of this study were to examine (a) the dry-land RT training practices and exercises used by elite swimming strength and conditioning coaches and (b) the rationale provided by coaches about their practices and prescription of specific dry-land RT training exercises. Twenty-three (n = 21 males, n = 2 females) elite swimming strength and conditioning coaches, from Ireland (n = 7), Great Britain (n = 5), Australia (n = 6), and the United States of America (n = 5) were recruited through their specific national governing bodies. Coaches completed an online questionnaire consisting of 7 sections; subject information, informed consent, coach's biography, coach education, current training commitments, dry-land RT training practices and exercises, and additional information. The results showed that coaches had varying levels of experience, education and worked with different level swimmers. A total of 95 dry-land RT training exercises were used by the coaches across 4 different dry-land RT training practices (warm-up, circuit training, traditional RT training and plyometrics). Traditional RT training (87%) was the most commonly practiced. The pull-up and squat were the most popular dry-land RT training exercises used by elite swimming strength and conditioning coaches. Future research needs to focus on exploring the specificity and the transfer of RT training exercises to swimming performance.

New hazards in paediatric poisoning presentations

Accidental ingestion is an important preventable cause of childhood morbidity. All accidental ingestion presentations (n = 478) to a tertiary paediatric ED from January 2010 to December 2011 were analysed. These results were compared with a similar study in the same institution ten years previously in 2001 and showed that while accidental ingestions constituted a higher proportion of presentations (0.5% in this study v 0.45% in 2001), fewer had investigations performed (21% v 35%) and fewer were admitted (7% v 20%). Accidental ingestions account for 0.5% of presentations and are an important focus of home safety information for parents and guardians. Paracetamol (n = 67, 14%) and liquid detergent capsules (n = 44, 9.2%) were the two most common substances implicated in these presentations, and have the potential to cause severe morbidity and mortality.

The addition of ondansetron to a oral rehydration protocol for children with acute gastroenteritis

This study describes the introduction of Ondansetron to an established waiting room Oral Rehydration Therapy (ORT) for Emergency Department (ED) children with acute gastroenteritis, and evaluates its impact on intravenous fluid administration and admissions. Children who failed initial ORT while waiting further medical assessment received Ondansetron and ORT reattempted. Data collected over a six week period in 2009 was compared to a similar period in 2008 when children received ORT without an anti-emetic. Outcome measures included intravenous fluid administration, admission. Rates of IVF administration reduced by 19% [88/215 (40.9%) in 2008, 51/234 (21.7%) in 2009, p < 0.0001] with a 1.6% reduction in admission rates [31/215 (14.41%) vs 30/234(12.82%) p=0.62]. Thirty four patients received Ondansetron, 79% were successfully rehydrated orally. The addition of Ondansetron to our established ORT programme has successfully reduced rates of IVF administration and admissions in children with gastroenteritis.

A phase I study of the safety and pharmacokinetics of the histone deacetylase inhibitor belinostat administered in combination with carboplatin and/or paclitaxel in patients with solid tumours

Background:

This phase I study assessed the maximum tolerated dose, dose-limiting toxicity (DLT) and pharmacokinetics of belinostat with carboplatin and paclitaxel and the anti-tumour activity of the combination in solid tumours.

Methods:

Cohorts of three to six patients were treated with escalating doses of belinostat administered intravenously once daily, days 1–5 q21 days; on day 3, carboplatin (area under the curve (AUC) 5) and/or paclitaxel (175 mg m⁻²) were administered 2–3 h after the end of the belinostat infusion.

Results:

In all 23 patients received 600–1000 mg m⁻² per day of belinostat with carboplatin and/or paclitaxel. No DLT was observed. The maximal administered dose of belinostat was 1000 mg m⁻² per day for days 1–5, with paclitaxel (175 mg m⁻²) and carboplatin AUC 5 administered on day 3. Grade III/IV adverse events were (n; %): leucopenia (5; 22%), neutropenia (7; 30%), thrombocytopenia (3; 13%) anaemia (1; 4%), peripheral sensory neuropathy (2; 9%), fatigue (1; 4%), vomiting (1; 4%) and myalgia (1; 4%). The pharmacokinetics of belinostat, paclitaxel and carboplatin were unaltered by the concurrent administration. There were two partial responses (one rectal cancer and one pancreatic cancer). A third patient (mixed mullerian tumour of ovarian origin) showed a complete CA-125 response. In addition, six patients showed a stable disease lasting ⩾6 months.

Conclusion:

The combination was well tolerated, with no evidence of pharmacokinetic interaction. Further evaluation of anti-tumour activity is warranted.

Pharmacokinetics (PK) of CR011-vcMMAE, an antibody-drug conjugate (ADC), in a phase (Ph) I study of patients (pts) with advanced melanoma

9063

Background: CR011-vcMMAE, an ADC of fully-human monoclonal anti-GPNMB antibody (Ab) with monomethylauristatin E (MMAE), is in Ph I/II trials in pts with melanoma and breast cancer. We report PK and toxicity data from a Ph I study in melanoma pts treated every (q) 3 weeks (w), qw, or 2 of 3w. Methods: Enzyme-linked immunosorbent assays were used to measure ADC, total Ab (TA), soluble GPNMB (sGPNMB), and anti-ADC Ab in pt samples. Free MMAE was measured by liquid chromatography/mass spectrometry. Results: Initially, 32 pts were treated in 9 cohorts of 0.03 to 2.63 mg/kg iv q3w using standard 3+3 dose escalation. Noncompartmental PK analysis showed dose-proportional TA, ADC and free MMAE levels. As previously reported, maximum tolerated dose (MTD) was 1.88 mg/kg iv q3w; dose limiting toxicity (DLT) was rash. At MTD (n=15), terminal phase half life (T½) of TA was 41 ± 25h and T½ of ADC was 29 ± 13h. Mean maximum plasma concentrations of free MMAE was 1.3–2.9% of TA concentration across all doses. Mean sGPNMB at baseline was 12 ng/ml (range 1.3–32 ng/ml), corresponding to 0.024 % of TA concentration at MTD. Anti-ADC Ab were detectible in 8/240 (3.3%) samples (n=54). Based on the T½, two additional dose schedules (qw and 2 out of 3w) were initiated (n=14). Pts received 0.75 mg/kg (n=3) and 1.0 mg/kg (n=5) in the qw schedule and 1.25 mg/kg (n=3) and 1.5 mg/kg (n=3) in 2 of 3w. The most common adverse events (AEs) were rash (n=6), pruritus (n=5) and fatigue (n=4). 1 DLT (Gr 3 rash) was observed at 1.0 mg/kg qw. Enrollment is ongoing in both schedules. Conclusions: The relatively short T½ of CR011-vcMMAE (∼40h) does not appear to be due to immunogenicity or sGPNMB-mediated clearance. Preliminary data suggest that weekly dosing is tolerated at higher per-cycle cumulative doses than the q3w schedule.

[Table: see text]

A phase I/II study of CR011-vcMMAE, an antibody-drug conjugate (ADC) targeting glycoprotein NMB (GPNMB) in patients (pts) with advanced melanoma

9032

Background: GPNMB is expressed on melanoma cells and represents a potential target for ADCs. CR011-vcMMAE is a fully-human monoclonal antibody to GPNMB conjugated to the tubulin inhibitor monomethylauristatin E (MMAE). Dose limiting toxicity in Phase I (n=32) was rash; tumor shrinkage including one partial response (PR) was observed. We now report Phase II data at the maximum tolerated dose of 1.88 mg/kg iv q3w. Methods: Eligible pts had unresectable stage III or stage IV melanoma and had received no more than 1 prior cytotoxic regimen but any number of other therapies. Pts received CR011-vcMMAE until disease progression (PD) or intolerable toxicity. The primary endpoint was overall response (ORR) by RECIST using a minimax two-stage design (p0=0.5; p1=0.2, α=β=0.1) with 18 patients in the first stage and a total of 32 pts. Secondary endpoints included progression free survival (PFS) and duration of response. Results: 36 pts (median age 67 years [range 37–79]; 94% stage IV; 68% M1c) were treated for a median of 2.4 months (m)(range 0.5–7.5m). 18 pts discontinued (14 PD, 2 consent, 1 adverse event [AE], 1 stable disease [SD]) and 18 pts were ongoing. The study met the criteria for advancement to the second stage; 4 PRs (1 unconfirmed) and 19 SD (range 1.7–7.5 mo) have been observed; final ORR is pending. The unconfirmed PR was in a pt with 96% tumor reduction and PD 6 weeks later. Median PFS was 4m. The most common AEs were rash (81%), fatigue (72%), alopecia (63%) and pruritus (56%). The most common grade 3/4 AEs were neutropenia (22%) and rash (19%). Grade 2 or higher rash was associated with longer PFS. Conclusions: CR011-vcMMAE is active and well-tolerated in heavily pretreated pts with advanced melanoma. Rash may be a useful biomarker for activity. More frequent dosing is being explored.

[Table: see text]

A phase I/II study of CR011-vcMMAE, an antibody-drug conjugate, in patients (pts) with locally advanced or metastatic breast cancer (MBC)

1067

Background: Glycoprotein NMB (GPNMB), also known as osteoactivin, has been shown to regulate metastasis of breast cancer in vivo. CR011-vcMMAE, a fully-human monoclonal anti-GPNMB antibody conjugated to the tubulin inhibitor monomethylauristatin E, is safe and active in pts with advanced melanoma. This is the first study of CR011-vcMMAE in breast cancer. Methods: Eligible pts with MBC had ≥ 2 prior chemotherapy regimens, including a taxane, an anthracycline, and capecitabine; and ECOG PS ≤ 2. Doses were escalated to 1.88 mg/kg IV q3w (the maximum tolerated dose [MTD] in melanoma) using a standard 3+3 design. Immunohistochemistry (IHC) with goat polyclonal antibody to GPNMB was performed on pt biopsy specimens and on tissue microarrays containing normal breast, DCIS, breast tumor and lymph node metastases. Results: 10 pts with MBC (median age 57, range 36 - 69) had a median of 7 prior regimens and were treated with CR011-vcMMAE for a median of 2 cycles (range 1–4). In the first 2 pts at 1.34 mg/kg, dose limiting toxicity of worsening peripheral sensory neuropathy was observed. Pts with baseline neuropathy worse than grade 1 were subsequently excluded. Pts were treated at 1.0 mg/kg (n = 3), 1.34 mg/kg (n = 5), and 1.88 mg/kg (n = 2); enrollment at 1.88 mg/kg is continuing. Other adverse events (AEs) were grade 1/2 anorexia and pain in 4 pts; diarrhea, rash, fatigue, and neuropathy in 3 pts; and grade 3 rash in 1 pt. Evidence of antitumor activity has been observed. A response of 37% tumor shrinkage was seen in a pt after only 2 cycles and is ongoing. A second pt had a 51% reduction after 2 cycles, but had PD after 12 weeks. Breast tumor samples were more likely to stain positive for GPNMB than normal breast tissues. Conclusions: CR011-vcMMAE 1.34 mg/kg IV q3w is well-tolerated in heavily pretreated pts with MBC. The 1.88 mg/kg q3w dose is being assessed and phase II expansion is planned at the MTD. IHC of pt tumor specimens is being evaluated.

[Table: see text]

A phase I study of oral belinostat (PXD101) in patients with advanced solid tumors

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Background: Belinostat (PXD101) is a hydroxamate HDAC inhibitor which demonstrates broad anti-neoplastic activity in vitro and in vivo. In Phase I studies in patients (pts) with advanced cancer, IV belinostat is well-tolerated up to 1000 mg/m2 daily x5. Preliminary results of an oral formulation of belinostat showed that the oral bioavailability was 20 - 50%. This Phase I trial of oral belinostat will determine the maximal tolerated dose (MTD) of once and twice daily dosing, tolerability and pharmacokinetics (PK) in pts with advanced solid tumors. Methods: Sequential cohorts of 3–6 pts with advanced solid tumors refractory to standard therapy or for which no standard therapy exists were administered belinostat 250–500mg once or twice daily in 4 week cycles. Fasting (day 1) and non-fasting (day 7) pharmacokinetic studies were performed on all patients along with serial ECGs to evaluate any potential effects on QTc prolongation. Patients were evaluated with routine blood work weekly and tumor imaging at the end of cycle 1 then every other cycle. Results: Sixteen pts have been treated in 3 dose levels at 250mg QD (6 pts), 500mg QD (6 pts) and 250mg BID (4 pts). The median number of cycles of therapy is 1 (range 1–5), nine pts continue to be treated. The most common reasons for discontinuation were adverse event (3 pts) and PD (3 pts). No DLTs were identified at 250mg QD or 250mg BID. DLTs of grade 3 dehydration and grade 3 fatigue were reported at 500mg QD. In pts from the first 3 dose cohorts, there were no grade 4/5 events reported. Other Grade 3 toxicities were fatigue (2 pts), abdominal pain (1 pt), ataxia (1 pt), prolonged INR (1 pt), prolonged PTT (1 pt) and confusion (1 pt). Symptoms were transient and usually resolved after drug was held. In > 500 ECG’s collected, there were no QTcF > 500 ms, and no QTcF increase > 60 ms above baseline. To date, the best clinical response observed has been SD in 7 patients. Conclusions: Oral belinostat at doses of 250mg QD and 250mg BID given on a continuous schedule appears to be well tolerated. Alternative dosing schedules are being explored to further dose escalate the belinostat. Updated safety, activity and pharmacokinetic data will be presented on these and alternate dose schedules.

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Dental caries and enamel fluorosis among the fluoridated population in the Republic of Ireland and non fluoridated population in Northern Ireland in 2002

BACKGROUND

An all Ireland/North South survey of Oral Health was carried out in 2001/2002.

AIMS

To compare levels of dental caries and enamel fluorosis among children and adolescents in the fluoridated Republic of Ireland (RoI) with those in the non fluoridated North of Ireland (NI).

METHODOLOGY

Cross sectional oral health survey of a representative, random, stratified sample of 5-, 8-, 12- and 15-year-olds in Rol and in NI (N = 19,950). WHO examination criteria with the addition of visible, non cavitated dentine caries were used for recording caries. Fluorosis was measured using Dean's Index.

RESULTS

In the RoI, the mean d(3c)mft / D(3c)MFT for 5-, 8-, 12-, and 15-year-olds with full domestic water fluoridation (n = 9,975), was 1.0, 0.3, 1.1 and 2.1 respectively. The corresponding means in non fluoridated NI (n = 1,475) were 1.8, 0.3, 1.5 and 3.6 respectively. (p < 0.0001, NS, p < 0.0005 and p < 0.0001). The prevalence of enamel fluorosis has increased in RoI since 1984, 23% and 36% of 8- and 15-year olds respectively in fluoridated areas had Dean's Index scores at the questionable or greater level in 2002 compared with 6% and 5% respectively in 1984.

CONCLUSIONS

In 2002 apart from 8-year-olds, caries levels were lower amongst children resident in fluoridated communities in RoI than amongst corresponding age groups in non-fluoridated NI. Caries has declined in fluoridated and non fluoridated groups in both jurisdictions since the early 1960s. In RoI fluorosis levels were higher amongst lifetime residents of fluoridated communities and have increased since 1984.

Parents' preference as to whether they would like to accompany their child when receiving dental treatment--results from a national survey

BACKGROUND AND DESIGN

parental accompaniment of children during dental treatment has always been a contentious issue. One of the factors that should be considered is the preference of the parents. The aim of this paper is to report the preference of parents of eight-year-old schoolchildren in Ireland in relation to accompanying their child during dental procedures and is part of the National Survey of Children's Dental Health in Ireland, which was conducted between October 2001 and June 2002. The survey had a cross sectional design and parents of children (average age 8.4 years) selected for dental examination were asked to complete a questionnaire.

RESULTS

3629 completed questionnaires were obtained from parents of eight-year-old children giving a response rate of 68 per cent. Sixty-seven per cent of parents expressed a preference to accompany their child during dental treatment, while nine per cent expressed a preference not to accompany their child. The sex of the child (p = 0.33) or the fact that the parents were holders of a medical card (surrogate for disadvantage) (p = 0.08) did not affect parents' preference. However, parents of a single child had a higher preference (78 per cent) for accompanying their child than did parents with greater than one child in the family unit (66 per cent) (p = 0.0009).

CONCLUSION

If given the choice, the majority of parents would prefer to accompany their child when receiving dental treatment.

Dental caries and enamel fluorosis among the fluoridated and non-fluoridated populations in the Republic of Ireland in 2002

BACKGROUND

A national survey of oral health of children and adolescents was carried out in the Republic of Ireland (RoI) in 2001/2002.

AIMS

To compare the prevalence of caries between child and adolescent residents in fluoridated and non-fluoridated communities in the RoI whilst controlling for disadvantage. To compare caries levels amongst disadvantaged and non-disadvantaged groups with and without water fluoridation. To report the changes in caries levels between the 1960s and 2002 in RoI. To report the changes in dental fluorosis levels between 1984 and 2002.

METHODOLOGY

Cross sectional oral health survey of a representative, random, stratified sample of 17,851 5-, 8-, 12- and 15-year-old children and adolescents in RoI. WHO examination criteria with the addition of visible, non-cavitated dentine caries were used for recording caries. Fluorosis was measured using Dean's Index.

RESULTS

In the RoI the mean dmft/DMFT scores for 5-, 8-, 12-, and 15-year-olds were 1.2, 0.3, 1.1 and 2.3. For those with domestic water fluoridation since birth the scores were 1.0, 0.3, 1.1 and 2.1 respectively. In non-fluoridated areas of RoI the mean dmft/DMFT scores for 5-, 8-, 12-, and 15-year-olds was 1.7, 0.3, 1.3 and 3.2, respectively. For 5-, 12- and 15-year-old age groups dental caries levels were lower amongst children with fluoridated domestic water supplies (all p<0.0001). The prevalence of dental fluorosis has increased in RoI since 1984. 23% and 36% of 8- and 15-year olds respectively in fluoridated areas had Dean's Index scores at the questionable or greater level in 2002, compared with 6% and 5% respectively in 1984.

CONCLUSIONS

Caries levels are lower among children with fluoridated domestic water supplies. Decay levels are much lower in 2002 than they were in 1984 and in the 1960s. The oral health of the less well off is worse than that of the rest of the population. The prevalence of dental fluorosis is higher amongst children and adolescents with fluoridated water supplies. Comparisons with 1984 data show an increase in the prevalence of fluorosis since that time.

Outcomes of patients with chronic renal insufficiency in the bypass angioplasty revascularization investigation

BACKGROUND

Although severe chronic kidney disease (CKD) is an independent predictor of mortality among patients with coronary artery disease, the impact of mild CKD on morbidity and mortality has not been fully defined.

METHODS AND RESULTS

Morbidity and mortality for the 3608 patients with multivessel coronary artery disease enrolled in the Bypass Angioplasty Revascularization Investigation randomized trial and registry were compared on the basis of the presence and absence of CKD, defined as a preprocedure serum creatinine level of >1.5 mg/dL. Seventy-six patients had CKD. Patients with renal insufficiency were older and more likely to have a history of diabetes, hypertension, and other comorbidities. Among patients undergoing PTCA, patients with CKD had a greater frequency of in-hospital death and cardiogenic shock (P<0.05 and 0.01, respectively). There was a trend toward a larger proportion of patients with CKD experiencing angina at 5 years (P=0.079). Patients with CKD had more cardiac admissions (P=0.003 and <0.0001 for patients undergoing PTCA and CABG, respectively) and a shorter time to subsequent CABG after initial revascularization than patients without CKD (P=0.01). CKD was associated with a higher risk of death at 7 years, both of all causes (relative risk 2.2, P<0.001) and of cardiac causes (relative risk 2.8, P<0.001).

CONCLUSIONS

CKD is associated with an increased risk of recurrent hospitalization, subsequent CABG, and mortality. This increased risk of death is independent of and additive to the risk associated with diabetes.

Polymerase eta and p53 jointly regulate cell survival, apoptosis and Mre11 recombination during S phase checkpoint arrest after UV irradiation

Xeroderma pigmentosum variant (XPV) cells lack the damage-specific polymerase eta and undergo a protracted arrest at the S phase checkpoint(s) following UV damage. The S phase checkpoints encompass several qualitatively different processes, and stimulate downstream events that are dependent on the functional state of p53. Primary fibroblasts with wild-type p53 arrest in S, and require a functional polymerase eta (pol eta) to carry out bypass replication, but do not recruit recombination factors for recovery. XPV cells with non-functional p53, as a result of transformation by SV40 or HPV16 (E6/E7), recruit the hMre11/hRad50/Nbs1 complex to arrested replication forks, coincident with PCNA, whereas normal transformed cells preferentially use the pol eta bypass replication pathway. The formation of hMre11 foci implies that arrested replication forks rapidly undergo a collapse involving double strand breakage and rejoining. Apoptosis occurs after UV only in cells transformed by SV40, and not in normal or XPV fibroblasts or HPV16 (E6/E7) transformed cells. Conversely, ultimate cell survival in XPV cells was much less in HPV16 (E6/E7) transformed cells than in SV40 transformed cells, indicating that apoptosis was not a reliable predictor of cell survival. Inhibition of p53 transactivation by pifithrin-alpha or inhibition of protein synthesis by cycloheximide did not induce hMre11 foci or apoptosis in UV damaged fibroblasts. Inhibition of kinase activity with wortmannin did not increase killing by UV, unlike the large increase seen with caffeine. Since HPV16 (E6/E7) transformed XPV cells were highly UV sensitive and not further sensitized by caffeine, it appears likely that caffeine sensitization proceeds through a p53 pathway. The S phase checkpoints are therefore, a complex set of different checkpoints that are coordinated by p53 with the capacity to differentially modulate cell survival, apoptosis, bypass replication and hMre11 recombination.

DNA polymerase eta undergoes alternative splicing, protects against UV sensitivity and apoptosis, and suppresses Mre11-dependent recombination

Polymerase eta (pol eta) is a low-fidelity DNA polymerase that is the product of the gene, POLH, associated with the human XP variant disorder in which there is an extremely high level of solar-induced skin carcinogenesis. The complete human genomic sequence spans about 40 kb containing 10 coding exons and a cDNA of 2.14 kb; exon I is untranslated and is 6 kb upstream from the first coding exon. Using bacterial artificial chromosomes (BACs), the gene was mapped to human chromosome band 6p21 and mouse band 17D. The gene is expressed in most tissues, except for very low or undetectable levels in peripheral lymphocytes, fetal spleen, and adult muscle; exon II, however, is frequently spliced out in normal cells and in almost half the transcripts in the testis and fetal liver. Expression of POLH in a multicopy episomal vector proved nonviable, suggesting that overexpression is toxic. Expression from chromosomally integrated linear copies using either an EF1-alpha or CMV promoter was functional, resulting in cell lines with low or high levels of pol eta protein, respectively. Point mutations in the center of the gene and in a C-terminal cysteine and deletion of exon II resulted in inactivation, but addition of a terminal 3 amino acid C-terminal tag, or an N- or C-terminal green fluorescent protein, had no effect on function. A low level of expression of pol eta eliminated hMre11 recombination and partially restored UV survival, but did not prevent UV-induced apoptosis, which required higher levels of expression. Polymerase eta is therefore involved in S-phase checkpoint and signal transduction pathways that lead to arrest in S, apoptosis, and recombination. In normal cells, the predominant mechanism of replication of UV damage involves pol eta-dependent bypass, and Mre11-dependent recombination that acts is a secondary, backup mechanism when cells are severely depleted of pol eta.

Celecoxib-induced Sweet's syndrome

Sweet's syndrome and related neutrophilic dermatoses have been associated with a variety of medications. Celecoxib is a new cyclo-oxygenase-2 inhibitor recently approved for arthritis. We describe a 57-year-old man who experienced tender pustulopapular lesions on the dorsal aspects of the hands, neck, and legs 1 week after starting celecoxib. Histopathologic examination of the lesion showed a diffuse dermal neutrophilic infiltrate, edema of the papillary dermis, spongiform pustules, and no leukocytoclastic vasculitis. These findings were consistent with Sweet's syndrome. Without realizing a possible association, the patient rechallenged himself with a second course of the medication, which resulted in a rapid exacerbation of his lesions. After discontinuing the medication for the second time, the patient has had complete clearing of his lesions. To our knowledge, this is the first report of Sweet's syndrome associated with this new class of nonsteroidal anti-inflammatory drugs.

Neonatal lupus erythematosus: an unusual congenital presentation with cutaneous atrophy, erosions, alopecia, and pancytopenia

Neonatal lupus erythematosus (NLE) is a rare disorder believed to be caused by the transplacental passage of specific autoantibodies from the mother to the fetus. Affected infants typically present with either characteristic skin lesions developing in the first month or later in life or congenital heart block. We report a very unusual case of NLE that was characterized by congenital skin atrophy, erosions, alopecia, and profound pancytopenia. Ro, La, and RNP antibodies were absent, and the diagnosis was made because of light microscopic and immunofluorescent findings. This case emphasizes that NLE can have widespread congenital skin involvement and suggests that at least some cases are mediated by antibodies other than Ro, La, and RNP.

Tyrosine phosphorylation and cytoskeletal tension regulate the release of fibroblast adhesions

We have investigated the mechanisms by which fibroblasts release their adhesions to the extracellular matrix substrata using a permeabilized cell system in which the adhesions remain relatively stable. A large number of different molecules were assayed for their effect on focal adhesion stability using immunofluorescence with antibodies against different focal adhesion constituents. ATP uniquely stimulates a rapid breakdown of focal adhesions, and at high ATP concentrations (> 5 mM), many cells are released from the dish. The remaining cells appear contracted with talin, alpha-actinin, and vinculin localized diffusely throughout the cell. Integrin containing tracks of variable intensity outline the regions where cells had resided before they detached from the substratum. At lower ATP concentrations (0.5-5 mM) the cells remain spread; however the focal adhesion components, including integrin, show an array of phenotypes ranging from diffusely localized throughout the cell to a localization in small, thin focal adhesions. Okadaic acid, a serine, threonine phosphatase inhibitor, enhances the contracted phenotype, even at low concentrations (0.5 mM) of ATP. The localization of focal adhesion components is different in okadaic acid-treated cells. In highly contracted cells, integrin is present in tracks where the cells resided before the contraction; however focal adhesions are no longer apparent. Talin, vinculin, and alpha-actinin localize in trabecular networks toward the periphery of the cell. Interestingly, phosphotyrosine staining as well as nascent, intracellular integrin precedes the recruitment of focal adhesion constituents into the trabecular network. The ATP-stimulated focal adhesion breakdown appears to operate through two mechanisms. First, ATP stimulates the tyrosine phosphorylation of several cytoskeletally associated proteins. These tyrosine phosphorylations correlated well with focal adhesion breakdown. Furthermore, addition of a recombinant, constitutively active tyrosine phosphatase inhibits both the tyrosine phosphorylations and the breakdown of the focal adhesions. None of the major tyrosine phosphoproteins are FAK, integrin, tensin, paxillin, or other phosphoproteins implicated in focal adhesion assembly. The second mechanism is cell contraction. High ATP concentrations, or lower ATP concentrations in the presence of okadaic acid induce cell contraction. Inhibiting the contraction by addition of a heptapeptide IRICRKG, which blocks the actin-myosin interaction, also inhibits focal adhesion breakdown. Neither the peptide nor the phosphatase inhibits focal adhesion breakdown under all conditions suggesting that both tension and tyrosine phosphorylations mediate the release of adhesions.

Medial collateral ligament knee sprains in college football. Effectiveness of preventive braces

This is the second of 2 articles on a 3-year investigation of medial collateral ligament sprains of the knee to assess the effectiveness of prophylactic knee braces in NCAA Division I college football players. Position, string, type of session, and daily brace wear were recorded. The injury rates for braced and unbraced knees were used to create an incidence density ratio. The data were stratified and simultaneously controlled for position, string, and session and evaluated for their statistical significance. The 987 Big Ten players generated 155,772 knee exposures over the study period (50% braced). Noticeable differences existed in the rates of injury for the braced and unbraced knees in almost every position during practices, depending on player or nonplayer status. When the influential factors of position, string, and session are considered, there is a consistent but not statistically significant tendency for the players wearing preventive knee braces to experience a lower injury rate than for their unbraced counterparts. For starters and substitutes in the line positions, as well as the linebackers and tight ends, there was a consistent trend toward a lower injury rate in both practices and games. The braced players in the skill positions (backs/kickers), at least during games, exhibited a higher injury rate.

Medial collateral ligament knee sprains in college football. Brace wear preferences and injury risk

In this prospective, multiinstitutional analysis of medial collateral ligament sprains in college football players, we categorized 987 previously uninjured study subjects according to frequency of wearing preventive knee braces, studied the patterns by which 47 of 100 injuries occurred to unbraced knees, and identified several extrinsic, sport-specific risk factors shared for both braced and unbraced knees. The attendance, brace wear choice, position, string, and session of each participant were recorded daily; medial collateral ligament sprains were reported whenever tissue damage was confirmed. Both the likelihood of wearing braces and risk of injury without them was highly dependent on session (games/practices), position group (line, linebacker/tight end, skill), and string group (players/nonplayers). Subjects wearing braces often faced a high injury risk to their unbraced knees, a finding compatible with the opinion that braces were a necessary evil, best worn when concern over danger of injury outweighed desire for speed and agility. It is concluded that to avoid misinterpretations due to the confounding influence of brace wear selection bias, accurate investigation of daily brace wear patterns is required. Then, before considing the impact of preventive knee braces, a repartitioning of the data base is essential to assure that only similar groups will be compared.

The alpha 1/beta 1 and alpha 6/beta 1 integrin heterodimers mediate cell attachment to distinct sites on laminin

This study was undertaken to determine the roles of individual alpha/beta 1 integrin heterodimers in promoting cellular interactions with the different attachment-promoting domains of laminin (LN). To do this, antibodies to the integrin beta 1 subunit or to specific integrin alpha subunits were tested for effects on cell attachment to LN, to elastase fragments E1-4 and E1, derived from the short arms and core of LN's cruciform structure, and to fragment E8 derived from the long arm of this structure. The human JAR choriocarcinoma cells used in this study attached to LN and to fragments E1 and E8. Attachment to E1-4 required a much higher substrate coating concentration, suggesting that it is a poor substrate for JAR cell attachment. The ability of cells to attach to different LN domains suggested the presence of more than one LN receptor. These multiple LN receptors were shown to be beta 1 integrin heterodimers because antibodies to the integrin beta 1 subunit inhibited attachment of JAR cells to LN and its three fragments. To identify the individual integrin alpha/beta 1 heterodimers that mediate interactions with these LN domains, mAbs specific for individual beta 1 heterodimers in human cells were used to study JAR cell interactions with LN and its fragments. An anti-alpha 6/beta 1-specific mAb, GoH3, virtually eliminated cell attachment to E8 and partially inhibited attachment to E1 and intact LN. Thus the major alpha 6/beta 1 attachment domain is present in fragment E8. An alpha 1/beta 1-specific mAb (S2G3) strongly inhibited cell attachment to collagen IV and partially inhibited JAR attachment to LN fragment E1. Thus, the alpha 1/beta 1 heterodimer is a dual receptor for collagen IV and LN, interacting with LN at a site in fragment E1. In combination, the anti-alpha 1- and anti-alpha 6-specific antibodies completely inhibited JAR cell attachment to LN and fragment E1. Thus, the alpha 1/beta 1 and alpha 6/beta 1 integrin heterodimers each function as LN receptors and act together to mediate the interactions of human JAR choriocarcinoma cells with LN.

Signal transduction through the fibronectin receptor induces collagenase and stromelysin gene expression

We have investigated the effects of ligation of the fibronectin receptor (FnR) on gene expression in rabbit synovial fibroblasts. Monoclonal antibodies to the FnR that block initial adhesion of fibroblasts to fibronectin induced the expression of genes encoding the secreted extracellular matrix-degrading metalloproteinases collagenase and stromelysin. That induction was a direct consequence of interaction with the FnR was shown by the accumulation of mRNA for stromelysin and collagenase. Monoclonal antibodies to several other membrane glycoprotein receptors had no effect on metalloproteinase gene expression. Less than 2 h of treatment of the fibroblasts with anti-FnR in solution was sufficient to trigger the change in gene expression, and induction was blocked by dexamethasone. Unlike other inducers of metalloproteinase expression, including phorbol diesters and growth factors, addition of the anti-FnR in solution to cells adherent to serum-derived adhesion proteins or collagen produced no detectable change in cell shape or actin microfilament organization. Inductive effects were potentiated by cross-linking of the ligand. Fab fragments of anti-FnR were ineffective unless cross-linked or immobilized on the substrate. Adhesion of fibroblasts to native fibronectin did not induce metallo-proteinases. However, adhesion to covalently immobilized peptides containing the arg-gly-asp sequence that were derived from fibronectin, varying in size from hexapeptides up to 120 kD, induced collagenase and stromelysin gene expression. This suggests that degradation products of fibronectin are the natural inductive ligands for the FnR. These data demonstrate that signals leading to changes in gene expression are transduced by the FnR, a member of the integrin family of extracellular matrix receptors. The signaling of changes in gene expression by the FnR is distinct from signaling involving cell shape and actin cytoarchitecture. At least two distinct signals are generated: the binding of fibronectin-derived fragments and adhesion-blocking antibodies to the FnR triggers events different from those triggered by binding of the native fibronectin ligand. Because the genes regulated by this integrin are for enzymes that degrade the extracellular matrix, these results suggest that information transduced by the binding of various ligands to integrins may orchestrate the expression of genes regulating cell behavior in the extracellular environment.

Melanoma cell adhesion to basement membrane mediated by integrin-related complexes

During invasion and metastasis, tumor cells use a variety of surface adhesion receptors to attach to and invade basement membranes and interstitial stroma. We examined the role of the cell surface integrin-like complex in the attachment of the invasive murine B16-BL6 melanoma cell line to basement membrane. Polyclonal antibodies prepared against integrin-related complexes isolated from hamster BHK cells (anti-ECMR) or mouse erythroleukemia cells (anti-mouse FnR) inhibited the attachment of B16 cells to complex basement membrane matrices and to substrates coated with purified extracellular matrix components (fibronectin, laminin, and type IV collagen). The expression of integrin-like receptors on the surface of B16 cells was confirmed by selective immunoprecipitation of radiolabeled and solubilized membrane proteins with the antibodies. Both antibodies also reacted with an integrin-related fibronectin-binding receptor complex purified by ligand affinity chromatography on fibronectin-Sepharose columns. The anti-integrin antibodies failed to react with the Mr 68,000 laminin-binding protein, suggesting that their inhibition of cell attachment to laminin and complex basement membrane was not due to contaminating antibodies against the Mr 68,000 laminin receptor. The results indicate that the integrin receptor complexes on B16-BL6 cells either interact directly with a diverse set of extracellular-matrix-associated components or somehow modulate the activity and function of other receptors. Thus integrins may have an important role in tumor cell invasion of tissue barriers.