Leveraging the Expertise of the CTSA Program to Increase the Impact and Efficiency of Clinical Trials

Importance

Multicenter clinical trials play a critical role in the translational processes that enable new treatments to reach all people and improve public health. However, conducting multicenter randomized clinical trials (mRCT) presents challenges. The Trial Innovation Network (TIN), established in 2016 to partner with the Clinical and Translational Science Award (CTSA) Consortium of academic medical institutions in the implementation of mRCTs, consists of 3 Trial Innovation Centers (TICs) and 1 Recruitment Innovation Center (RIC). This unique partnership has aimed to address critical roadblocks that impede the design and conduct of mRCTs, in expectation of accelerating the translation of novel interventions to clinical practice. The TIN's challenges and achievements are described in this article, along with examples of innovative resources and processes that may serve as useful models for other clinical trial networks providing operational and recruitment support.

Observations

The TIN has successfully integrated more than 60 CTSA institution program hubs into a functional network for mRCT implementation and optimization. A unique support system for investigators has been created that includes the development and deployment of novel tools, operational and recruitment services, consultation models, and rapid communication pathways designed to reduce delays in trial start-up, enhance recruitment, improve engagement of diverse research participants and communities, and streamline processes that improve the quality, efficiency, and conduct of mRCTs. These resources and processes span the clinical trial spectrum and enable the TICs and RIC to serve as coordinating centers, data centers, and recruitment specialists to assist trials across the National Institutes of Health and other agencies. The TIN's impact has been demonstrated through its response to both historical operational challenges and emerging public health emergencies, including the national opioid public health crisis and the COVID-19 pandemic.

Conclusions and Relevance

The TIN has worked to reduce barriers to implementing mRCTs and to improve mRCT processes and operations by providing needed clinical trial infrastructure and resources to CTSA investigators. These resources have been instrumental in more quickly and efficiently translating research discoveries into beneficial patient treatments.

The RIC Recruitment & Retention Materials Toolkit - a resource for developing community-informed study materials

Clinical trials face many challenges with meeting projected enrollment and retention goals. A study's recruitment materials and messaging convey necessary key information and therefore serve as a critical first impression with potential participants. Yet study teams often lack the resources and skills needed to develop engaging, culturally tailored, and professional-looking recruitment materials. To address this gap, the Recruitment Innovation Center recently developed a Recruitment & Retention Materials Content and Design Toolkit, which offers research teams guidance, actionable tips, resources, and customizable templates for creating trial-specific study materials. This paper seeks to describe the creation and contents of this new toolkit.

Approaches for enhancing the informativeness and quality of clinical trials: Innovations and principles for implementing multicenter trials from the Trial Innovation Network

One challenge for multisite clinical trials is ensuring that the conditions of an informative trial are incorporated into all aspects of trial planning and execution. The multicenter model can provide the potential for a more informative environment, but it can also place a trial at risk of becoming uninformative due to lack of rigor, quality control, or effective recruitment, resulting in premature discontinuation and/or non-publication. Key factors that support informativeness are having the right team and resources during study planning and implementation and adequate funding to support performance activities. This communication draws on the experience of the National Center for Advancing Translational Science (NCATS) Trial Innovation Network (TIN) to develop approaches for enhancing the informativeness of clinical trials. We distilled this information into three principles: (1) assemble a diverse team, (2) leverage existing processes and systems, and (3) carefully consider budgets and contracts. The TIN, comprised of NCATS, three Trial Innovation Centers, a Recruitment Innovation Center, and 60+ CTSA Program hubs, provides resources to investigators who are proposing multicenter collaborations. In addition to sharing principles that support the informativeness of clinical trials, we highlight TIN-developed resources relevant for multicenter trial initiation and conduct.

Mechanisms to expedite pediatric clinical trial site activation: The DOSE trial experience

BACKGROUND

Timely trial start-up is a key determinant of trial success; however, delays during start-up are common and costly. Moreover, data on start-up metrics in pediatric clinical trials are sparse. To expedite trial start-up, the Trial Innovation Network piloted three novel mechanisms in the trial titled Dexmedetomidine Opioid Sparing Effect in Mechanically Ventilated Children (DOSE), a multi-site, randomized, double-blind, placebo-controlled trial in the pediatric intensive care setting.

METHODS

The three novel start-up mechanisms included: 1) competitive activation; 2) use of trial start-up experts, called site navigators; and 3) supplemental funds earned for achieving pre-determined milestones. After sites were activated, they received a web-based survey to report perceptions of the DOSE start-up process. In addition to perceptions, metrics analyzed included milestones met, time to start-up, and subsequent enrollment of subjects.

RESULTS

Twenty sites were selected for participation, with 19 sites being fully activated. Across activated sites, the median (quartile 1, quartile 3) time from receipt of regulatory documents to site activation was 82 days (68, 113). Sites reported that of the three novel mechanisms, the most motivating factor for expeditious activation was additional funding available for achieving start-up milestones, followed by site navigator assistance and then competitive site activation.

CONCLUSION

Study start-up is a critical time for the success of clinical trials, and innovative methods to minimize delays during start-up are needed. Milestone-based funds and site navigators were preferred mechanisms by sites participating in the DOSE study and may have contributed to the expeditious start-up timeline achieved.

CLINICALTRIALS

gov #: NCT03938857.

A community-informed recruitment plan template to increase recruitment of racial and ethnic groups historically excluded and underrepresented in clinical research

INTRODUCTION

Engaging communities in research planning and implementation can enhance recruitment and retention (R&R) of racial and ethnic groups historically excluded and underrepresented in clinical research; however, most studies do not use community-informed approaches. This paper describes the formative research process used to design a Community-Informed Recruitment Plan Template for racial and ethnic groups historically excluded and underrepresented in clinical research.

METHODS

Using an existing R&R template as a starting point, we iteratively developed and refined the community-informed template through a 3-phase process to achieve cultural-appropriateness. Phase 1 included a literature review, 34 community engagement (CE) studios to review recommendations, community advisory board (CAB) review, and survey data from minority recruitment experts. Phase 2 involved integration of content into existing R&R template. Phase 3 was a final review and revision using input of the CAB and researchers' panel. Survey data collected in Phase 1 were analyzed using descriptives (i.e., frequencies and percentages). Open-ended survey responses were analyzed using inductive, qualitative thematic analysis.

RESULTS

The final 8-section template can help develop effective grant or proposal language where study R&R plans are requested. They include: 1) Recruitment Strategy; 2) A Stakeholder Communication Plan; 3) Evidence of Recruitment Feasibility; 4) Recruitment and Retention Team; 5) Recruitment and Retention Methods; 6) Recruitment and Retention Timeline; 7) Evaluation; and 8) Budget.

CONCLUSIONS

Incorporating multiple perspectives into this formative research process enhances the cultural appropriateness of this community-informed R&R template to help research teams achieve R&R goals for individuals historically excluded and underrepresented in clinical research.

Recruitment and retention for chronic pain clinical trials: a narrative review

Opioid misuse is at a crisis level. In response to this epidemic, the National Institutes of Health has funded $945 million in research through the Helping to End Addiction Long-term (HEAL) Pain Management Initiative, including funding to the Vanderbilt Recruitment Innovation Center (RIC) to strategize methods to catalyze participant recruitment. The RIC, recognizing the challenges presented to clinical researchers in recruiting individuals experiencing pain, conducted a review of evidence in the literature on successful participant recruitment methods for chronic pain trials, in preparation for supporting the HEAL Pain trials. Study design as it affects recruitment was reviewed, with issues such as sufficient sample size, impact of placebo, pain symptom instability, and cohort characterization being identified as problems. Potential solutions found in the literature include targeted electronic health record phenotyping, use of alternative study designs, and greater clinician education and involvement. For retention, the literature reports successful strategies that include maintaining a supportive staff, allowing virtual study visits, and providing treatment flexibility within the trial. Community input on study design to identify potential obstacles to recruitment and retention was found to help investigators avoid pitfalls and enhance trust, especially when recruiting underrepresented minority populations. Our report concludes with a description of generalizable resources the RIC has developed or adapted to enhance recruitment and retention in the HEAL Pain studies. These resources include, among others, a Recruitment and Retention Plan Template, a Competing Trials Tool, and MyCap, a mobile research application that interfaces with Research Electronic Data Capture (REDCap).

A survey of patients with laryngotracheal stenosis on future clinical trial design

BACKGROUND/AIMS

Laryngotracheal stenosis is a rare but devastating proximal airway fibrosis that restricts a patient's ability to breathe. Treatment is primarily surgical and to date, there has never been a multi-institutional, randomized, prospective, and interventional clinical trial for a medical therapy to treat laryngotracheal stenosis. Therefore, we aimed to obtain patient feedback to guide successful trial design, recruitment, retention, and for identifying potential barriers to study participation.

METHODS

Over 1000 members of an international laryngotracheal stenosis online support community (the Living with Idiopathic Subglottic Stenosis Facebook group) were sent two questionnaires for a proposed interventional double-blinded, randomized, placebo-controlled clinical trial.

RESULTS

A total of 317 and 558 participants responded to the first and second surveys, respectively. The majority of participants (77%) were willing to consider enrollment, regardless of having a 50% chance of receiving placebo versus treatment (78%). The majority (84%) of participants were willing to travel 200 miles to participate for up to six in-person visits over 50 days. Specific side effects, including anemia/thrombocytopenia (72%) or risk of infection (69.3%) had the greatest impact on clinical trial participation with other side effects (peripheral edema (53%), oral ulcers (51%), and gastrointestinal side effects (41%)) having less impact.

CONCLUSION

Patients with laryngotracheal stenosis possess nuanced insight into their disease and treatment options. As a group, they are extremely motivated for better therapies. Future laryngotracheal stenosis clinical trials should focus on providing excellent side effect -related education and utilizing feedback from online advocacy groups to optimize recruitment and retention.

Beliefs about inevitable decline among home-living older adults at risk of malnutrition: a qualitative study

BACKGROUND

Approximately 14% of free-living adults aged ≥65 years are at risk of malnutrition. Malnutrition screen and treat interventions in primary care are few, show mixed results, and the advice given is not always accepted and followed. We need to better understand the experiences and contexts of older adults when aiming to develop interventions that are engaging, optimally persuasive and relevant.

METHODS

Using the Person-based Approach, we carried out 23 semi-structured interviews with purposively selected adults ≥65 years with chronic health or social conditions associated with malnutrition risk. Thematic analysis informed the development of key principles to guide planned intervention development.

RESULTS

We found that individuals' beliefs about an inevitable decline in appetite and eating in older age compound the many and varied physical and physiological barriers that they experience. Also, we found that expectations of decline in appetite and physical ability may encourage resignation, reduce self-efficacy to overcome barriers, and reduce motivation to address weight loss and/or recognise it as an issue that needs to be addressed. Fear of loss of independence may also reduce the likelihood of asking general practitioners for advice.

CONCLUSIONS

The key findings identified include a sense of resignation, multiple different barriers to eating and a need for independence, each underpinned by the expectation of a decline in older adulthood. Interventions need to address misperceptions about the inevitability of decline, highlight how and why diet recommendations are somewhat different from recommendations for the general population, and suggest easy ways to increase food intake that address common barriers.

Harmonizing Clinical Sequencing and Interpretation for the eMERGE III Network

The advancement of precision medicine requires new methods to coordinate and deliver genetic data from heterogeneous sources to physicians and patients. The eMERGE III Network enrolled >25,000 participants from biobank and prospective cohorts of predominantly healthy individuals for clinical genetic testing to determine clinically actionable findings. The network developed protocols linking together the 11 participant collection sites and 2 clinical genetic testing laboratories. DNA capture panels targeting 109 genes were used for testing of DNA and sample collection, data generation, interpretation, reporting, delivery, and storage were each harmonized. A compliant and secure network enabled ongoing review and reconciliation of clinical interpretations, while maintaining communication and data sharing between clinicians and investigators. A total of 202 individuals had positive diagnostic findings relevant to the indication for testing and 1,294 had additional/secondary findings of medical significance deemed to be returnable, establishing data return rates for other testing endeavors. This study accomplished integration of structured genomic results into multiple electronic health record (EHR) systems, setting the stage for clinical decision support to enable genomic medicine. Further, the established processes enable different sequencing sites to harmonize technical and interpretive aspects of sequencing tests, a critical achievement toward global standardization of genomic testing. The eMERGE protocols and tools are available for widespread dissemination.

Ethical Considerations Related to Return of Results from Genomic Medicine Projects: The eMERGE Network (Phase III) Experience

We examined the Institutional Review Board (IRB) process at 9 academic institutions in the electronic Medical Records and Genomics (eMERGE) Network, for proposed electronic health record-based genomic medicine studies, to identify common questions and concerns. Sequencing of 109 disease related genes and genotyping of 14 actionable variants is being performed in ~28,100 participants from the 9 sites. Pathogenic/likely pathogenic variants in actionable genes are being returned to study participants. We examined each site’s research protocols, informed-consent materials, and interactions with IRB staff. Research staff at each site completed questionnaires regarding their IRB interactions. The time to prepare protocols for IRB submission, number of revisions and time to approval ranged from 10–261 days, 0–11, and 11–90 days, respectively. IRB recommendations related to the readability of informed consent materials, specifying the full range of potential risks, providing options for receiving limited results or withdrawal, sharing of information with family members, and establishing the mechanisms to answer participant questions. IRBs reviewing studies that involve the return of results from genomic sequencing have a diverse array of concerns, and anticipating these concerns can help investigators to more effectively engage IRBs.

Abstract 294: Post-Discharge Phone Calls: Efficient Opportunity to Assess and Improve Patient Adherence to Care Plan

Background: Transitioning from hospital to home is a common failure point in care delivery and patient adherence to a plan of care. Our post-discharge phone calls helped identify gaps (especially related to medications) and assign accountability for addressing issues.

Method: We reached more than 200 patients with Acute Coronary Syndrome and Congestive Heart Failure by phone 24-48 hours after discharge between 8/2011 - 1/2012. We tested two operating models: hospital nurse with knowledge of admission (n=200) vs. clinic nurse with ongoing responsibility for managing patient (n=10 and ongoing). Callers used a standardized script and documentation form with “teach-back” methodology.

Outcomes (Figure): Medications issues (65%, 107 of 165) included errors in discharge meds lists that contributed to patient misunderstandings and lack of adherence. Most (63%, 89 of 142) patients left the hospital without a scheduled follow-up appointment (revealing systematic improvement need). Callers provided teaching and reinforcement and triaged issues, avoiding at least 3 - 4 probable readmissions. Comparing two delivery models (hospital vs. clinic nurse) yielded notable differences. For both groups, calls took ∼15+ minutes (min=6, max=48). However, prep time, documentation and follow-up were significantly longer for hospital nurses (35 mins) than clinic nurses (15 mins). The hospital nurse spent more time “mining” records to understand each patient story; clinic nurses could prioritize calls and personalize content based on prior relationships with patients. Issues were quickly handled by clinic nurses in face-to-face provider interactions, whereas the hospital nurse frequently became mired in lengthy back-and-forth clinical communication.

Conclusion: Analysis of post-discharge phone calls shows that some patients (new diagnoses, complicated medications regimen) may particularly benefit; however, the call represented a valuable reinforcement opportunity for all patients we reached. Optimally efficient, effective calls require: 1) Reliable patient contact information; 2) Clear record of plan of care, including accurate medications list; 3) Follow-up appointments scheduled; 4) Caller expertise with diagnoses; and 5) Caller prior relationship with the patient. Going forward, our team will continue to test clinic-based post-discharge phone calls, evaluating several key metrics including ability of patients to successfully articulate their medications and follow-up plans, % of patients who attend their follow-up appointments, readmission rates, et al.

Impact of oedema on recovery after major abdominal surgery and potential value of multifrequency bioimpedance measurements

Background

The consequences of generalized oedema following major abdominal surgery are under-recognized, and its causes are poorly understood.

Methods

Thirty-eight patients (21 men and 17 women) were observed for the occurrence of oedema after major abdominal surgery. Oedema formation was related to fluid balance, changes in whole-body bioimpedance (Z) measured at four frequencies (5, 50, 100 and 200 kHz), and clinical outcome.

Results

The 20 patients who developed oedema were older than those who did not (mean(s.d.) 73(9) versus 63(14) years; P = 0·007). Fluid intake over the first 5 days after surgery was similar in both groups, but those with oedema excreted less total fluid (16·9(2·4) versus 19·7(3·5) litres; P = 0·022). Oedema was associated with a delay in tolerating solid food (P = 0·001) and opening bowels (P = 0·020), a prolonged hospital stay (median 17 (range 8–59) versus 9 (range 4–27) days; P = 0·001) and more postoperative complications (13 of 20 versus four of 18 patients; P = 0·011). The preoperative ratio of whole-body impedance at 200 kHz to that at 5 kHz was higher in those who subsequently developed oedema (0·81(0·03) versus 0·78(0·02); P = 0·015).

Conclusion

The development of oedema after major abdominal surgery is associated with increased morbidity. Age and reduced ability to excrete administered fluid load are significant aetiological factors and bioimpedance analysis can potentially identify patients at risk.

Early hormonal therapy stabilizes hemodynamics during donor procurement

BACKGROUND

Hemodynamic instability has been implicated in the loss of otherwise transplantable organs. We examined the hypothesis that administration of hormonal therapy early during donor management would stabilize hemodynamics and increase the number of organs procured.

METHODS

We retrospectively analyzed 133 consecutive donor records from a single organ procurement organization. Controls (C) received no early hormonal therapy. A steroid group (S) received methylprednisolone only and a combination hormonal therapy group (CH) received thyroxine, methylprednisolone, dextrose, and insulin at the start of donor management (t(0h)). Adrenergic support was adjusted to maintain mean arterial blood pressure (MAP) at > or =60 mm Hg. Doses of adrenergic agents were assessed at t(0h), 4 hours (t(4h)), and just prior to procurement (t(proc)).

RESULTS

Baseline characteristics were similar in all groups. Dosages of adrenergic agents decreased over time in all groups. A significant decrease in adrenergic requirements was seen in the CH group compared with the C group at t(4h) and t(proc). A trend toward decreased adrenergic requirements was noted in S compared with C at t(4h) and t(proc). Slightly more total organs were procured from S and CH compared with C.

CONCLUSIONS

Significantly less adrenergic support was required with early use of CH. A similar (although nonsignificant) reduction was seen with S. The benefit(s) of CH vs corticosteroids alone remains uncertain and requires further study.

Role of Activated Protein C in the Pathophysiology of Severe Sepsis

Sepsis is a complex syndrome that can lead to multiple organ failure and death. Severe sepsis has been associated with mortality rates ranging from 28% to 50% and is the most common cause of death in the noncardiac intensive care unit. Despite advances in both antibiotic therapy and supportive care, the mortality rate due to severe sepsis has remained fundamentally unchanged in the past several decades. With increased understanding of the pathophysiology of sepsis, particularly the intricate interplay between activation of coagulation and inflammation, novel therapeutic agents that may improve clinical outcomes are being researched and developed. The epidemiology, pathophysiology, and treatment of severe sepsis are reviewed. Also discussed are the recently published results from a multicenter, randomized, placebo-controlled phase 3 clinical trial of drotrecogin alfa (activated), a recombinant form of human activated protein C, in patients with severe sepsis. The nursing implications of this new approved therapy are discussed.

Role of activated protein C in the pathophysiology of severe sepsis

Sepsis is a complex syndrome that can lead to multiple organ failure and death. Severe sepsis has been associated with mortality rates ranging from 28% to 50% and is the most common cause of death in the noncardiac intensive care unit. Despite advances in both antibiotic therapy and supportive care, the mortality rate due to severe sepsis has remained fundamentally unchanged in the past several decades. With increased understanding of the pathophysiology of sepsis, particularly the intricate interplay between activation of coagulation and inflammation, novel therapeutic agents that may improve clinical outcomes are being researched and developed. The epidemiology, pathophysiology, and treatment of severe sepsis are reviewed. Also discussed are the recently published results from a multicenter, randomized, placebo-controlled phase 3 clinical trial of drotrecogin alfa (activated), a recombinant form of human activated protein C, in patients with severe sepsis. The nursing implications of this new approved therapy are discussed.

Methods for the stable isotopic analysis of chlorine in chlorate and perchlorate compounds

Chlorate and perchlorate compounds, used as herbicides, solid fuel propellants, and explosives, are increasingly recognized as pollutants in groundwater. Stable isotope characterization would permit both environmental monitoring of extent of remediation and forensic characterization. Stoichiometric reduction to chloride (greater than 98% yield), by Fe(II) for chlorate and alkaline fusion-decomposition for perchlorate, allows analysis by standard methods to give highly reproducible and accurate delta37Cl results (0.05/1000, 2 x standard error). Analysis of various compounds from different suppliers yielded delta37Cl values for chlorate samples near to +0.2/1000 (SMOC), but one has within-sample heterogeneity of 0.5/1000, possibly due to crystallization processes during manufacture. Results for perchlorate samples also are generally near +0.2/1000, but one is +2.3/1000 (SMOC). The initial results suggest that both forensic and environmental applications might be feasible.

Comparison of calcaneal ultrasound and DXA to assess the risk of corticosteroid-induced osteoporosis: a cross-sectional study

Patients on long-term oral corticosteroids have an increased risk of low bone mass and fragility fractures. Fracture risk rises soon after commencement of corticosteroid therapy and it is possible that these agents adversely influence bone architecture disproportionately to their effect on bone mass. The best means of assessing bone status in patients using corticosteroids remains uncertain, but quantitative ultrasound of the calcaneus may provide evidence of microarchitectural changes not detected by dual-energy X-ray absorptiometry (DXA). Patients with Crohn's disease have an increased risk of low bone mineral density (BMD), the etiology of which is multifactorial but includes corticosteroid use. We studied 118 consecutive patients with Crohn's disease, 21 of whom used continuous oral corticosteroids, 70 of whom were intermittent users, and 27 who had never used the drug. All patients received DXA of the lumbar spine, hip and calcaneus and quantitative ultrasound (QUS) of the calcaneus. The different techniques were compared using a femoral neck T-score < or = -1.5 as the threshold of corticosteroid-induced osteoporosis. When compared with the femoral neck T-score, there were no significant differences between the predictive values of lumbar spine DXA, calcaneal DXA or calcaneal QUS to identify low femoral neck BMD. However, the absolute T-score required to give similar discriminatory capacity to femoral neck T-score varied substantially (T= -0.81 to -1.5) between the different measurement techniques and sites.

Cloning and expression of the histo-blood group Pk UDP-galactose: Ga1beta-4G1cbeta1-cer alpha1, 4-galactosyltransferase. Molecular genetic basis of the p phenotype

The molecular genetic basis of the P histo-blood group system has eluded characterization despite extensive studies of the biosynthesis of the P(1), P, and P(k) glycolipids. The main controversy has been whether a single or two distinct UDP-Gal:Galbeta1-R 4-alpha-galactosyltransferases catalyze the syntheses of the structurally related P(1) and P(k) antigens. The P(1) polymorphism is linked to 22q11.3-ter. Data base searches with the coding region of an alpha4GlcNAc-transferase identified a novel homologous gene at 22q13.2 designated alpha4Gal-T1. Expression of full coding constructs of alpha4Gal-T1 in insect cells revealed it encoded P(k) but not P(1) synthase activity. Northern analysis showed expression of the transcript correlating with P(k) synthase activity and antigen expression in human B cell lines. Transfection of P(k)-negative Namalwa cells with alpha4Gal-T1 resulted in strong P(k) expression. A single homozygous missense mutation, M183K, was found in six Swedish individuals of the rare p phenotype, confirming that alpha4Gal-T1 represented the P(k) gene. Sequence analysis of the coding region of alpha4Gal-T1 in P(1)+/- individuals did not reveal polymorphisms correlating with P(1)P(2) typing.

Long-term maintenance of weight loss following supplemented fasting

One hundred two obese subjects were evaluated 2-3 years following treatment in a combined behavior therapy and very low calorie diet (VLCD) program. Average weight loss after VLCD was 27.2 kg; average weight loss at follow-up was 11.3 kg. Subjects who reported high levels of exercise were more successful in maintaining weight loss (17.5 kg at follow-up) than were those who exercised only moderately (9.3 kg), or not at all (5.6 kg). Enrolling in a weight loss maintenance program also minimized weight regain. Subjects who participated in maintenance for more than 8 months sustained more average weight loss at follow-up (19.1 kg) than did subjects who participated for 8 months or less (10.6 kg), or subjects who did not participate in maintenance (6.6 kg).

Dual analyte immunoassay in neural tube defect and Down's syndrome screening: results of a multicentre clinical trial

We report a multicentre clinical field trial of a novel dual analyte enzyme immunoassay method for the simultaneous measurement of alpha-fetoprotein (AFP) and free beta-human choriogonadotropin (hCG) in the same microtitre well. The assay was shown to have good technical performance in the hands of all trial centres, with between assay coefficients of variation better than 10% for both analyte across the whole of the assay ranges. The method compared well with single analyte measuring procedures and produced acceptable performance as judged by external quality assurance criteria. Recovery of added analyte and analyte dilution curves also showed acceptable performance. In clinical evaluation of a large set of neural tube defect cases, good clinical discrimination from unaffected cases was observed using AFP. With over 150 Down's syndrome cases, the combination of AFP and free beta hCG confirmed the high detection rates achievable using this marker combination, with detection rates in excess of 70% in early gestation. We conclude that the combination of clinically superior markers coupled with technologically innovative assay design will lead to more efficient Down's screening programmes.

A specific type of ganglioside as a modulator of insulin-dependent cell growth and insulin receptor tyrosine kinase activity. Possible association of ganglioside-induced inhibition of insulin receptor function and monocytic differentiation induction in HL-60 cells

Insulin-dependent cell growth has been correlated with insulin receptor function, particularly receptor-associated kinase activity, in in vitro studies. The insulin-dependent phosphorylation of the 95-kDa receptor subunit was clearly inhibited, in a concentration-dependent manner, by the presence of unbranched neolacto series gangliosides having a NeuAc2----3Gal terminus, particularly 2----3-sialosylparagloboside (2----3SPG; IV3NeuAc-nLc4), but not by other gangliosides with a NeuAc2----6Gal terminus or by branched neolacto series gangliosides (e.g. G10). Such inhibition of phosphorylation was minimal with ganglio series gangliosides and negligible with sphingosine, neutral glycolipids, or sulfatide. 2----3SPG did not affect insulin binding to the insulin receptor. Insulin-dependent cell growth and its inhibition by 2----3SPG were observed in three human cell lines so far tested: lymphoid cell line IM9, promyelocytic leukemia cell line HL-60, and erythroleukemia cell line K562. Since IM9 cells contain a much higher quantity of insulin receptor than do HL-60 or K562 cells, insulin-dependent receptor phosphorylation and its inhibition by 2----3SPG in intact cells were clearly observed with IM9 cells. Receptor phosphorylation in intact cells was inhibited when cells were preincubated in the presence of 2----3SPG. Insulin-dependent growth of HL-60 and K562 cells was also inhibited by prolonged culture (96-144 h) with exogenous 2----3SPG. Subsequent to the inhibition of insulin-dependent HL-60 cell growth, a remarkable phenotypic transformation was observed, i.e. changes in morphology, enzymes, and cell-surface markers to those characteristic of monocytes. The level of 2----3SPG in HL-60 cells increased when cells were cultured with 1 alpha,25-dihydroxyvitamin D3 to the same degree seen in cells cultured with 5 microM 2----3SPG. Both these treatments led to inhibition of insulin-dependent cell growth, followed by induction of monocytic differentiation. Thus, the cellular level of 2----3SPG may modulate insulin-dependent cell growth and define the lineage specificity of differentiation through modulation of receptor-associated kinase activity.

Cellular and humoral mediators of sepsis syndrome

The story of mediators in sepsis syndrome is developing extremely rapidly and continues to unfold. This discussion has focused on those areas most studied and those that have the greatest clinical implications in the context of current knowledge. There are a number of mediators under active investigation that have not been reviewed here because their discussion is beyond the scope of this article. Just how all the pieces of the intricate cascade of events ultimately fit together is yet to be seen. However, the availability of important probes, such as cyclooxygenase inhibitors, TNF, anti-TNF, IL1, anti-IL1, anti-proteases, antioxidants, and antiendotoxin, is allowing major progress to be made in a short period of time. Transferring this knowledge to the bedside and everyday clinical practice is a slower process, but the prospects are bright for innovative new therapies for sepsis syndrome, septic shock, and the multiple organ failure associated with these clinical entities.

Surgical management of Wolff-Parkinson-White syndrome in infants and small children

Surgical ablation of accessory conduction pathways has rarely been reported in infants and small children with Wolff-Parkinson-White syndrome. In the interval January 1985 to September 1988, 19 infants and children aged 5 or younger have undergone surgical ablation of accessory conduction pathways because of recurrent supraventricular tachycardia. There were 12 (63%) boys and seven (37%) girls. Age ranged from 4 to 66 months (mean 33.8 months). Nine infants were less than 24 months old. Weight ranged from 5.5 to 2.16 kg (mean 13.2 kg). All 19 patients had symptoms, with duration of symptoms ranging from 3 to 63 months (mean 21 months). Accessory conduction pathways were classified preoperatively as left free wall in four (21%), right free wall in nine (47%), and posterior septal in six (32%). No multiple pathways were recognized preoperatively. Left ventricular function was abnormal in four (21%) preoperatively. Free wall pathways (n = 13) were surgically dissected and septal pathways (n = 6) were cryoablated at -70 degrees C. Mean cardiopulmonary bypass time was 60 +/- 4 minutes. Mean crossclamp time was 42 +/- 2 minutes in those undergoing surgical dissection. Mean postoperative stay was 6.4 +/- 0.2 days. There were no deaths, no significant postoperative complications, and no instance of complete heart block. All patients were considered cured at the time of discharge. At a mean follow-up of 12.7 months, 18 (94.7%) remain cured. One patient with Ebstein's anomaly and a right free wall pathway had a recurrent supraventricular tachycardia 3 months postoperatively, and repeat electrophysiologic study has shown a previously unsuspected anterior septal pathway. Ventricular function returned to normal in all four patients who had abnormal function preoperatively. Surgical ablation of accessory conduction pathways can be safely done in infants and small children with results equal to those obtained in adults.

Isolation to homogeneity and partial characterization of a histo-blood group A defined Fuc alpha 1----2Gal alpha 1----3-N-acetylgalactosaminyltransferase from human lung tissue

The soluble histo-blood group A glycosyltransferase (Fuc alpha 1----Gal alpha 1----3-N-acetylgalactosaminyltransferase) was purified approximately 600,000-fold to homogeneity from human lung tissue. The enzyme was solubilized in 1% Triton X-100, partially purified by affinity chromatography on Sepharose 4B, and eluted with UDP. Final purification was obtained by twice repeated fast protein liquid chromatography ion exchange (Mono STM) with NaCl gradient elution and reverse-phase chromatography (proRPC) with acetonitrile gradient elution. Identity of the purified protein was established by (i) demonstration of the putative A transferase protein only in affinity-purified extracts of A but not O individuals, and (ii) specific immunoprecipitation of enzyme activity and putative protein with monoclonal antibodies. Sodium dodecyl sulfate electrophoresis revealed a single protein band with apparent Mr of approximately 40,000 under both reducing and nonreducing conditions. Digestion with N-glycanase yielded a reduction in Mr of approximately 6,000 (estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis), suggesting that the A transferase is a glycoprotein with N-linked carbohydrate chains. Amino acid composition and N-terminal amino acid sequence of the intact transferase, as well as of peptides released by endolysyl peptidase digest or cyanogen bromide cleavage, are presented.

Specific interaction between Lex and Lex determinants. A possible basis for cell recognition in preimplantation embryos and in embryonal carcinoma cells

The Lex determinant (Gal beta 1----4[Fuc alpha 1----3]GlcNAc-beta 1----R) has been implicated as having a role in mediating compaction of the mouse embryo at the morula stage (Fenderson, B., Zehavi, U., and Hakomori, S. (1984) J. Exp. Med. 160, 1591-1596). Here, we present evidence suggesting a role for Lex in F9 embryonal carcinoma cell adhesion and a mechanism for Lex recognition based on carbohydrate-carbohydrate interaction. Homotypic aggregation of F9 cells was inhibited by lacto-N-fucopentaose III, and F9 cells showed a preferential interaction with Lex liposomes. The following observations suggest that the structure capable of recognizing Lex per se on F9 cells is Lex: (i) Cell surface-labeled components solubilized in octylglucoside, affinity-bound on an Lex-octyl-Sepharose column, contained glycoproteins reactive with anti-Lex antibody. (ii) Liposomes containing Lex showed significant interaction with Lex glycolipid, but not other glycolipids, coated on a plastic surface. (iii) Liposomes containing Lex glycolipid were found to self-aggregate, whereas liposomes containing paragloboside (nLc4) or sialylparagloboside (IV3NeuAcnLc4) did not. (iv) The diffusibility of 3H-labeled lacto-N-fucopentaitol III (but not I or II), incubated with Lex liposome, from the lower to the upper Boyden chamber through a semipermeable membrane was inhibited. In all these experiments (i-iv), the interaction of Lex to Lex (or Lex to lacto-N-fucopentaose III) was clearly observed only in the presence of Ca2+ and Mg2+ and was enhanced by the presence of Mn2+. These interactions were inhibited by EDTA. The results suggest the novel hypothesis that carbohydrate-carbohydrate interactions may play an important role in controlling cell recognition during F9 cell aggregation and during embryonic development.

Monoclonal antibodies directed to the blood group A associated structure, galactosyl-A: specificity and relation to the Thomsen-Friedenreich antigen

Two monoclonal antibodies, HH8 and HH9, have been established after immunization of mice with galactosyl-A glycolipid antigen having the terminal structure, Gal beta 1----3GalNAc alpha 1----3[Fuc alpha 1----2]Gal beta 1----R, which is the precursor for type 3 chain A (repetitive A) and type 3 chain H (A-associated H). Both antibodies react strongly and specifically with galactosyl-A, but HH8 (IgM) showed strong hemagglutination of blood group A1, A2, O and B erythrocytes after sialidase treatment, while HH9 (IgG1) did not react with human erythrocytes even after sialidase treatment. HH8 and anti-T antibody, but not HH9, reacted with glycophorin A after sialidase treatment. The reactivity of HH8 with glycophorin A was abolished by beta-galactosidase and was inhibited by liposomes containing galactosyl-A, but not other glycolipids. In addition, anti-T antibody and peanut lectin reacted specifically with galactosyl-A glycolipids. These findings indicate that HH8 recognizes the terminal disaccharide Gal beta 1----3GalNAc alpha 1----R, which is the same sequence as the classically known Thomsen-Friedenreich antigen (T-antigen), whereas HH9 does not cross-react with T-antigen but recognizes the entire galactosyl-A structure. The T-antigen was also demonstrated by immunohistology with HH8 after neuraminidase treatment in a subset of cells in stratified epithelium.

Isolation and characterization of novel glycolipids with blood group A-related structures: galactosyl-A and sialosylgalactosyl-A

Two glycosphingolipids with the following novel structures have been isolated from human blood cells and characterized by NMR, direct probe mass spectrometry, fast atom bombardment-mass spectrometry, and methylation analysis: (Formula: see text). Both structure i and structure ii are characterized by substitution of beta-galactosyl or sialosyl-beta-galactosyl residue at the terminal alpha-GalNAc residue of blood group A determinant and are therefore specific products associated with the blood group A phenotype.

Scott: 75 years on

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Hydroxyethyl starch in priming fluid for cardiopulmonary bypass

The physiochemical characteristics of hydroxyethyl starch make it suitable for use as a colloidal blood plasma substitute. In high doses, this drug may interfere with blood coagulation. Because of its effectiveness and low cost, we have used hydroxyethyl starch rather than albumin in the priming fluid for cardiopulmonary bypass: 500 ml of 6% hydroxyethyl starch and 2,000 ml of lactated Ringer's solution. To determine if excessive bleeding has been associated with the use of hydroxyethyl starch, we reviewed 760 cardiac operations. The patients were 49.9 +/- 0.5 years old (mean +/- SEM) and weighed 73 +/- 1 kg. Blood loss during the first postoperative day was 578 +/- 25 ml, and 4.0 +/- 0.2 units of bank blood were utilized in the perioperative period. We have used an improved method of administering heparin and protamine for the past 3 years. In the 461 patients operated upon since then, blood loss was 437 +/- 21 ml, 2.9 +/- 0.1 units of bank blood were used, and excessive postoperative bleeding necessitated re-exploration in nine patients (2.0%). These results compare favorably with other recently published series in which hydroxyethyl starch was not used in the pump prime. Thus the dose of hydroxyethyl starch in our priming fluid does not appear to be associated with excessive bleeding. In view of its safety and low cost, hydroxyethyl starch is a suitable colloidal blood plasma substitute for use during cardiopulmonary bypass.