The Annual Wellness Visit Health Risk Assessment: Potential of Patient Portal-Based Completion and Patient-Oriented Education and Support

Background and Objectives

Patient portals are secure online platforms that allow patients to perform electronic health management tasks and engage in bidirectional information exchange with their care team. Some health systems administer Medicare Annual Wellness Visit (AWV) health risk assessments through the patient portal. Scalable opportunities from portal-based administration of risk assessments are not well understood. Our objective is 2-fold-to understand who receives vs misses an AWV and health risk assessment and explore who might be missed with portal-based administration.

Research Design and Methods

This is an observational study of electronic medical record and patient portal data (10/03/2021-10/02/2022) for 12 756 primary care patients 66+ years from a large academic health system.

Results

Two-thirds (n = 8420) of older primary care patients incurred an AWV; 81.0% of whom were active portal users. Older adults who were active portal users were more likely to incur AWV than those who were not, though portal use was high in both groups (81.0% with AWV vs 76.8% without; p < .001). Frequently affirmative health risk assessment categories included falls/balance concerns (44.2%), lack of a documented advanced directive (42.3%), sedentary behaviors (39.9%), and incontinence (35.1%). Mean number of portal messages over the 12-month observation period varied from 7.2 among older adults affirmative responses to concerns about safety at home to 13.8 for older adults who reported difficulty completing activities of daily living. Portal messaging varied more than 2-fold across affirmative health risk categories and were marginally higher with greater number affirmative (mean = 13.8 messages/year no risks; 19.6 messages/year 10+ risks).

Discussion and Implications

Most older adults were active portal users-a group more likely to have incurred a billed AWV. Efforts to integrate AWV risk assessments in the patient portal may streamline administration and scalability for dissemination of tailored electronically mediated preventive care but must attend to equity issues.

Tau seeding without tauopathy

Neurodegenerative tauopathies such as Alzheimer's disease (AD) are caused by brain accumulation of tau assemblies. Evidence suggests tau functions as a prion, and cells and animals can efficiently propagate unique, transmissible tau pathologies. This suggests a dedicated cellular replication machinery, potentially reflecting a normal physiologic function for tau seeds. Consequently, we hypothesized that healthy control brains would contain seeding activity. We have recently developed a novel monoclonal antibody (MD3.1) specific for tau seeds. We used this antibody to immunopurify tau from the parietal and cerebellar cortices of 19 healthy subjects without any neuropathology, ranging 19 to 65 years. We detected seeding in lysates from the parietal cortex, but not in the cerebellum. We also detected no seeding in brain homogenates from wildtype or human tau knockin mice, suggesting that cellular/genetic context dictates development of seed-competent tau. Seeding did not correlate with subject age or brain tau levels. We confirmed our essential findings using an orthogonal assay, real-time quaking-induced conversion, which amplifies tau seeds in vitro. Dot blot analyses revealed no AT8 immunoreactivity above background levels in parietal and cerebellar extracts and ∼1/100 of that present in AD. Based on binding to a panel of antibodies, the conformational characteristics of control seeds differed from AD, suggesting a unique underlying assembly, or structural ensemble. Tau's ability to adopt self-replicating conformations under nonpathogenic conditions may reflect a normal function that goes awry in disease states.

Circulating neutrophils from patients with early breast cancer have distinct subtype-dependent phenotypes

PURPOSE

An elevated number of circulating neutrophils is a poor prognostic factor for breast cancer, where evidence of bone marrow cancer-dependent priming is found. However, how early this priming is detectable remains unclear.

PATIENTS AND METHODS

Here, we investigate changes in circulating neutrophils from newly diagnosed breast cancer patients before any therapeutic interventions. To do this, we assessed their lifespan and their broader intracellular kinase network activation states by using the Pamgene Kinome assay which measures the activity of neutrophil kinases.

RESULTS

We found sub-type specific L-selectin (CD62L) changes in circulating neutrophils as well as perturbations in their overall global kinase activity. Strikingly, breast cancer patients of different subtypes (HR+, HER2+, triple negative) exhibited distinct neutrophil kinase activity patterns indicating that quantifiable perturbations can be detected in circulating neutrophils from early breast cancer patients, that are sensitive to both hormonal and HER-2 status. We also detected an increase in neutrophils lifespan in cancer patients, independently of tumour subtype.

CONCLUSIONS

Our results suggest that the tumour-specific kinase activation patterns in circulating neutrophils may be used in conjunction with other markers to identify patients with cancer from those harbouring only benign lesions of the breast. Given the important role neutrophil in breast cancer progression, the significance of this sub-type of specific priming warrants further investigation.

Histone H3 serotonylation dynamics in dorsal raphe nucleus contribute to stress- and antidepressant-mediated gene expression and behavior

Background

Major depressive disorder (MDD), along with related mood disorders, is a debilitating illness that affects millions of individuals worldwide. While chronic stress increases incidence levels of mood disorders, stress-mediated disruptions in brain function that precipitate these illnesses remain elusive. Serotonin-associated antidepressants (ADs) remain the first line of therapy for many with depressive symptoms, yet low remission rates and delays between treatment and symptomatic alleviation have prompted skepticism regarding precise roles for serotonin in the precipitation of mood disorders. Our group recently demonstrated that serotonin epigenetically modifies histone proteins (H3K4me3Q5ser) to regulate transcriptional permissiveness in brain. However, this phenomenon has not yet been explored following stress and/or AD exposures.

Methods

We employed a combination of genome-wide and biochemical analyses in dorsal raphe nucleus (DRN) of male and female mice exposed to chronic social defeat stress to examine the impact of stress exposures on H3K4me3Q5ser dynamics, as well as associations between the mark and stress-induced gene expression. We additionally assessed stress-induced regulation of H3K4me3Q5ser following AD exposures, and employed viral-mediated gene therapy to reduce H3K4me3Q5ser levels in DRN and examine the impact on stress-associated gene expression and behavior.

Results

We found that H3K4me3Q5ser plays important roles in stress-mediated transcriptional plasticity. Chronically stressed mice displayed dysregulated H3K4me3Q5ser dynamics in DRN, with both AD- and viral-mediated disruption of these dynamics proving sufficient to rescue stress-mediated gene expression and behavior.

Conclusions

These findings establish a neurotransmission-independent role for serotonin in stress-/AD-associated transcriptional and behavioral plasticity in DRN.

Participatory evaluation of the process of co-producing resources for the public on data science and artificial intelligence

BACKGROUND

The growth of data science and artificial intelligence offers novel healthcare applications and research possibilities. Patients should be able to make informed choices about using healthcare. Therefore, they must be provided with lay information about new technology. A team consisting of academic researchers, health professionals, and public contributors collaboratively co-designed and co-developed the new resource offering that information. In this paper, we evaluate this novel approach to co-production.

METHODS

We used participatory evaluation to understand the co-production process. This consisted of creative approaches and reflexivity over three stages. Firstly, everyone had an opportunity to participate in three online training sessions. The first one focused on the aims of evaluation, the second on photovoice (that included practical training on using photos as metaphors), and the third on being reflective (recognising one's biases and perspectives during analysis). During the second stage, using photovoice, everyone took photos that symbolised their experiences of being involved in the project. This included a session with a professional photographer. At the last stage, we met in person and, using data collected from photovoice, built the mandala as a representation of a joint experience of the project. This stage was supported by professional artists who summarised the mandala in the illustration.

RESULTS

The mandala is the artistic presentation of the findings from the evaluation. It is a shared journey between everyone involved. We divided it into six related layers. Starting from inside layers present the following experiences (1) public contributors had space to build confidence in a new topic, (2) relationships between individuals and within the project, (3) working remotely during the COVID-19 pandemic, (4) motivation that influenced people to become involved in this particular piece of work, (5) requirements that co-production needs to be inclusive and accessible to everyone, (6) expectations towards data science and artificial intelligence that researchers should follow to establish public support.

CONCLUSIONS

The participatory evaluation suggests that co-production around data science and artificial intelligence can be a meaningful process that is co-owned by everyone involved.

ZBTB7A regulates MDD-specific chromatin signatures and astrocyte-mediated stress vulnerability in orbitofrontal cortex

Hyperexcitability in the orbitofrontal cortex (OFC) is a key clinical feature of anhedonic domains of Major Depressive Disorder (MDD). However, the cellular and molecular substrates underlying this dysfunction remain unknown. Here, cell-population-specific chromatin accessibility profiling in human OFC unexpectedly mapped genetic risk for MDD exclusively to non-neuronal cells, and transcriptomic analyses revealed significant glial dysregulation in this region. Characterization of MDD-specific cis-regulatory elements identified ZBTB7A - a transcriptional regulator of astrocyte reactivity - as an important mediator of MDD-specific chromatin accessibility and gene expression. Genetic manipulations in mouse OFC demonstrated that astrocytic Zbtb7a is both necessary and sufficient to promote behavioral deficits, cell-type-specific transcriptional and chromatin profiles, and OFC neuronal hyperexcitability induced by chronic stress - a major risk factor for MDD. These data thus highlight a critical role for OFC astrocytes in stress vulnerability and pinpoint ZBTB7A as a key dysregulated factor in MDD that mediates maladaptive astrocytic functions driving OFC hyperexcitability.

'In the picture': perspectives on living and working with cancer

We explored working and living with cancer at a large research-intensive National Health Service hospital breast cancer service and adjoining non-governmental organisation (NGO). The project had three elements that were largely autonomous in practice but conceptually integrated through a focus on personalised cancer medicine. Di Sherlock held conversations with staff and patients from which she produced a collection of poems, Written Portraits At the same time, we conducted interviews and observation in the hospital, and hosted a public series of science cafés in the NGO. The trajectory of this project was not predetermined, but we found that the poetry residency provided a context for viewing participation in experimental cancer care and vice versa. Taking themes from the poetry practice, we show how they revealed categories of relevance to participants and illuminated others that circulated in the hospital and NGO. Reciprocally, turning to findings from long-term ethnographic research with patients, we show that their observations were not only representations but also tools for navigating life in waiting with cancer. The categories that we discovered and assembled about living and working with cancer do not readily combine into an encompassing picture, we argue, but instead provide alternating perspectives. Through analysis of different forms of research participation, we hope to contribute to an understanding of how categories are made, recognised and inhabited through situated comparisons. In personalised medicine, category-making is enabled if not dependent on increasingly intensive computation and so the practices seem far removed from mundane processes of interaction. Yet, we emphasise connections with everyday practices, in which people categorise themselves and others routinely according to what they like and resemble.

Comparison of phenomics and cfDNA in a large breast screening population: the Breast Screening and Monitoring Study (BSMS)

To assess their roles in breast cancer diagnostics, we aimed to compare plasma cell-free DNA (cfDNA) levels with the circulating metabolome in a large breast screening cohort of women recalled for mammography, including healthy women and women with mammographically detected breast diseases, ductal carcinoma in situ and invasive breast cancer: the Breast Screening and Monitoring Study (BSMS). In 999 women, plasma was analyzed by nuclear magnetic resonance (NMR) and Ultra-Performance Liquid Chromatography-Mass Spectrometry (UPLC-MS) and then processed to isolate and quantify total cfDNA. NMR and UPLC-MS results were compared with data for 186 healthy women derived from the AIRWAVE cohort. Results showed no significant differences between groups for all metabolites, whereas invasive cancers had significantly higher plasma cfDNA levels than all other groups. When stratified the supervised OPLS-DA analysis and total cfDNA concentration showed high discrimination accuracy between invasive cancers and the disease/medication-free subjects. Furthermore, comparison of OPLS-DA data for invasive breast cancers with the AIRWAVE cohort showed similar discrimination between breast cancers and healthy controls. This is the first report of agreement between metabolomics and plasma cfDNA levels for discriminating breast cancer from healthy subjects in a true screening population. It also emphasizes the importance of sample standardization. Follow on studies will involve analysis of candidate features in a larger validation series as well as comparing results with serial plasma samples taken at the next routine screening mammography appointment. The findings here help establish the role of plasma analysis in the diagnosis of breast cancer in a large real-world cohort.

Communication of Diagnostic Uncertainty in Primary Care and Its Impact on Patient Experience: an Integrative Systematic Review

BACKGROUND

Diagnostic uncertainty is a pervasive issue in primary care where patients often present with non-specific symptoms early in the disease process. Knowledge about how clinicians communicate diagnostic uncertainty to patients is crucial to prevent associated diagnostic errors. Yet, in-depth research on the interpersonal communication of diagnostic uncertainty has been limited. We conducted an integrative systematic literature review (PROSPERO CRD42020197624, unfunded) to investigate how primary care doctors communicate diagnostic uncertainty in interactions with patients and how patients experience their care in the face of uncertainty.

METHODS

We searched MEDLINE, PsycINFO, and Linguistics and Language Behaviour Abstracts (LLBA) from inception to December 2021 for MeSH and keywords related to 'communication', 'diagnosis', 'uncertainty' and 'primary care' environments and stakeholders (patients and doctors), and conducted additional handsearching. We included empirical primary care studies published in English on spoken communication of diagnostic uncertainty by doctors to patients. We assessed risk of bias with the QATSDD quality assessment tool and conducted thematic and content analysis to synthesise the results.

RESULTS

Inclusion criteria were met for 19 out of 1281 studies. Doctors used two main communication strategies to manage diagnostic uncertainty: (1) patient-centred communication strategies (e.g. use of empathy), and (2) diagnostic reasoning strategies (e.g. excluding serious diagnoses). Linguistically, diagnostic uncertainty was either disclosed explicitly or implicitly through diverse lexical and syntactical constructions, or not communicated (omission). Patients' experiences of care in response to the diverse communicative and linguistic strategies were mixed. Patient-centred approaches were generally regarded positively by patients.

DISCUSSION

Despite a small number of included studies, this is the first review to systematically catalogue the diverse communication and linguistic strategies to express diagnostic uncertainty in primary care. Health professionals should be aware of the diverse strategies used to express diagnostic uncertainty in practice and the value of combining patient-centred approaches with diagnostic reasoning strategies.

Shallow WGS of individual CTCs identifies actionable targets for informing treatment decisions in metastatic breast cancer

BACKGROUND

We report copy-number profiling by low-pass WGS (LP-WGS) in individual circulating tumour cells (CTCs) for guiding treatment in patients with metastatic breast cancer (MBC), comparing CTC results with mutations detected in circulating tumour DNA (ctDNA) in the same blood samples.

METHODS

Across 10 patients with MBC who were progressing at the time of blood sampling and that had >20 CTCs detected by CellSearch®, 63 single cells (50 CTCs and 13 WBCs) and 16 cell pools (8 CTC pools and 8 WBC pools) were recovered from peripheral blood by CellSearch®/DEPArray™ and sequenced with Ampli1 LowPass technology (Menarini Silicon Biosystems). Copy-number aberrations were identified using the MSBiosuite software platform, and results were compared with mutations detected in matched plasma cfDNA analysed by targeted next-generation sequencing using the Oncomine™ Breast cfDNA Assay (Thermo Fisher).

RESULTS

LP-WGS data demonstrated copy-number gains/losses in individual CTCs in regions including FGFR1, JAK2 and CDK6 in five patients, ERBB2 amplification in two HER2-negative patients and BRCA loss in two patients. Seven of eight matched plasmas also had mutations in ctDNA in PIK3CA, TP53, ESR1 and KRAS genes with mutant allele frequencies (MAF) ranging from 0.05 to 33.11%. Combining results from paired CTCs and ctDNA, clinically actionable targets were identified in all ten patients.

CONCLUSION

This combined analysis of CTCs and ctDNA may offer a new approach for monitoring of disease progression and to direct therapy in patients with advanced MBC, at a time when they are coming towards the end of other treatment options.

Chromatin profiling in human neurons reveals aberrant roles for histone acetylation and BET family proteins in schizophrenia

Schizophrenia (SZ) is a psychiatric disorder with complex genetic risk dictated by interactions between hundreds of risk variants. Epigenetic factors, such as histone posttranslational modifications (PTMs), have been shown to play critical roles in many neurodevelopmental processes, and when perturbed may also contribute to the precipitation of disease. Here, we apply an unbiased proteomics approach to evaluate combinatorial histone PTMs in human induced pluripotent stem cell (hiPSC)-derived forebrain neurons from individuals with SZ. We observe hyperacetylation of H2A.Z and H4 in neurons derived from SZ cases, results that were confirmed in postmortem human brain. We demonstrate that the bromodomain and extraterminal (BET) protein, BRD4, is a bona fide 'reader' of H2A.Z acetylation, and further provide evidence that BET family protein inhibition ameliorates transcriptional abnormalities in patient-derived neurons. Thus, treatments aimed at alleviating BET protein interactions with hyperacetylated histones may aid in the prevention or treatment of SZ.

Personalising clinical pathways in a London breast cancer service

Using interview and observational data from a busy and research-intensive breast cancer service in the United Kingdom, we discuss recent developments in personalised medicine. Specifically, we show how clinical and research practices meet in clinical pathways that are reconfigured in response to changing approaches of diagnosing, monitoring, treating and understanding cancers. Clinical pathways are increasingly sensitive to changes in evidence deduced through new technologies and therapies as well as decisions based on intensive, iterative analysis of data collected across a range of platforms. We contribute to existing research by showing how the organisation of clinical pathways both maintains established clinical practices and responds to new research evidence, managing a threshold between evidence-based and experimental medicine. Finally, we invite comparisons with other forms of personalisation to understand how they depend on the 'real time' collection, analysis and application of data.

How patients describe their diagnosis compared to clinical documentation

OBJECTIVES

To explore how patients describe their diagnoses following Emergency Department (ED) discharge, and how this compares to electronic medical record (EMR) documentation.

METHODS

We conducted a cohort study of patients discharged from three EDs. Patients completed questionnaires regarding their understanding of their diagnosis. Inclusion criteria: adult ED patients aged 18 and older seen within the last seven days. We independently compared patient-reported new diagnoses following discharge to EMR-documented diagnoses regarding diagnostic content (identical, insignificantly different, different, not enough detail) and the level of technical language in diagnostic description (technical, semi-technical, lay).

RESULTS

The majority of participants (n=95 out of 137) reported receiving a diagnosis and stated the given diagnosis. Of those who reported their diagnosis, 66%, were females (n=62), the average age was 43 (SD 16), and a fourth (n=24) were Black and 66% (n=63) were white. The majority (84%) described either the same or an insignificantly different diagnosis. For 11% the patient-reported diagnosis differed from the one documented. More than half reported their diagnosis using semi-technical (34%) or technical language (26%), and over a third (40%) described their diagnosis in lay language.

CONCLUSIONS

Patient-reported diagnoses following ED discharge had moderate agreement with EMR-documented diagnoses. Findings suggest that patients might reproduce verbatim semi-technical or technical diagnoses they received from clinicians, but not fully understood what the diagnosis means for them.

Centralized registry for COVID-19 research recruitment: Design, development, implementation, and preliminary results

BACKGROUND

The Coronavirus Disease 2019 (COVID-19) pandemic has had substantial global morbidity and mortality. Clinical research related to prevention, diagnosis, and treatment of COVID-19 is a top priority. Effective and efficient recruitment is challenging even without added constraints of a global pandemic. Recruitment registries offer a potential solution to slow or difficult recruitment.

OBJECTIVES

The purpose of this paper is to describe the design and implementation of a digital research recruitment registry to optimize awareness and participant enrollment for COVID-19-related research in Baltimore and to report preliminary results.

METHODS

Planning began in March 2020, and the registry launched in July 2020. The primary recruitment mechanisms include electronic medical record data, postcards distributed at testing sites, and digital advertising campaigns. Following consent in a Research Electronic Data Capture survey, participants answer questions related to COVID-19 exposure, testing, and willingness to participate in research. Branching logic presents participants with studies they might be eligible for.

RESULTS

As of March 24, 2021, 9010 participants have enrolled, and 64.2% are female, 80.6% are White, 9.4% are Black or African American, and 6% are Hispanic or Latino. Phone outreach has had the highest response rate (13.1%), followed by email (11.9%), text (11.4%), and patient portal message (9.4%). Eleven study teams have utilized the registry, and 4596 matches have been made between study teams and interested volunteers.

CONCLUSION

Effective and efficient recruitment strategies are more important now than ever due to the time-limited nature of COVID-19 research. Pilot efforts have been successful in connecting interested participants with recruiting study teams.

The critical need for nursing education to address the diagnostic process

Diagnostic errors are among the most common medical errors and the deadliest. The National Academy of Medicine recently concluded that diagnostic errors represent an urgent national concern. Their first recommendation to address this issue called for promoting the key role of the nurse in the diagnostic process. Registered nurses across clinical settings significantly contribute to the medical diagnostic process, though their role in diagnosis has historically gone unacknowledged. In this paper, we review the history and current state of diagnostic education in pre-licensure registered nurse preparation, introduce interprofessional individual- and team-based competencies to improve diagnostic safety, and discuss the next steps for nursing education. Nurses educated and empowered to fully participate in the diagnostic process are essential for achieving better, safer patient outcomes.

Machine learning reveals bilateral distribution of somatic L1 insertions in human neurons and glia

Retrotransposons can cause somatic genome variation in the human nervous system, which is hypothesized to have relevance to brain development and neuropsychiatric disease. However, the detection of individual somatic mobile element insertions presents a difficult signal-to-noise problem. Using a machine-learning method (RetroSom) and deep whole-genome sequencing, we analyzed L1 and Alu retrotransposition in sorted neurons and glia from human brains. We characterized two brain-specific L1 insertions in neurons and glia from a donor with schizophrenia. There was anatomical distribution of the L1 insertions in neurons and glia across both hemispheres, indicating retrotransposition occurred during early embryogenesis. Both insertions were within the introns of genes (CNNM2 and FRMD4A) inside genomic loci associated with neuropsychiatric disorders. Proof-of-principle experiments revealed these L1 insertions significantly reduced gene expression. These results demonstrate that RetroSom has broad applications for studies of brain development and may provide insight into the possible pathological effects of somatic retrotransposition.

Use of electronic recruitment methods in a clinical trial of adults with gout

BACKGROUND/AIMS

Electronic-based recruitment methods are increasingly utilized in clinical trials to recruit and enroll research participants. The cost-effectiveness of electronic-based methods and impact on sample generalizability is unknown. We compared recruitment yields, cost-effectiveness, and demographic characteristics across several electronic and traditional recruitment methods.

METHODS

We analyzed data from the diet gout trial recruitment campaign. The diet gout trial was a randomized, controlled, cross-over trial that examined the effects of a dietary approaches to stop hypertension (DASH)-like diet on uric acid levels in adults with gout. We used four electronic medical record and four non-electronic medical record-based recruitment methods to identify and recruit potentially eligible participants. We calculated the response rate, screening visit completion rate, and randomization rate for each method. We also determined cost per response, the screening, and randomization for each method. Finally, we compared the demographic characteristics among individuals who completed the screening visit by recruitment method.

RESULTS

Of the 294 adults who responded to the recruitment campaign, 51% were identified from electronic medical record-based methods. Patient portal messaging, an electronic medical record-based method, resulted in the highest response rate (4%), screening visit completion rate (37%), and randomization rate (21%) among these eight methods. Electronic medical record-based methods ($60) were more cost-effective per response than non-electronic medical record-based methods ($107). Electronic-based methods, including patient portal messaging and Facebook, had the highest proportion of White individuals screened (52% and 60%). Direct mail to non-active patient portal increased enrollment of traditionally under-represented groups, including both women and African Americans.

CONCLUSION

An electronic medical record-based recruitment strategy that utilized the electronic medical record for participant identification and postal mailing for participant outreach was cost-effective and increased participation of under-represented groups. This hybrid strategy represents a promising approach to improve the timely execution and broad generalizability of future clinical trials.

Disentangling Race, Poverty, and Place to Understand the Racial Disparity in Waist Circumference among Women

In the U.S., 54.8% of non-Hispanic Black women are obese, a rate that is 1.4 times greater than in White women. The drivers of this racial disparity are not yet clearly understood. We sought to disentangle race, household poverty, neighborhood racial composition, and neighborhood poverty to better understand the racial disparity in obesity among women. We used data from the 1999-2004 National Health and Nutrition Examination Survey and the 2000 U.S. Census to examine the role of individual race, individual poverty, neighborhood racial composition, and neighborhood poverty on women's risk of obesity. We found that individual race was the primary risk factor for obesity among women. Neighborhood effects did not account for the racial disparity. Understanding that race is a social, not a biologic construct, more work is needed to uncover what it is about race that produces racial disparities in obesity among women.

Plasma cell-free DNA (cfDNA) as a predictive and prognostic marker in patients with metastatic breast cancer

BACKGROUND

Breast cancer (BC) is the most common cancer in women, and despite the introduction of new screening programmes, therapies and monitoring technologies, there is still a need to develop more useful tests for monitoring treatment response and to inform clinical decision making. The purpose of this study was to compare circulating cell-free DNA (cfDNA) and circulating tumour cells (CTCs) with conventional breast cancer blood biomarkers (CA15-3 and alkaline phosphatase (AP)) as predictors of response to treatment and prognosis in patients with metastatic breast cancer (MBC).

METHODS

One hundred ninety-four female patients with radiologically confirmed MBC were recruited to the study. Total cfDNA levels were determined by qPCR and compared with CELLSEARCH® CTC counts and CA15-3 and alkaline phosphatase (AP) values. Blood biomarker data were compared with conventional tumour markers, treatment(s) and response as assessed by RECIST and survival. Non-parametric statistical hypothesis tests were used to examine differences, correlation analysis and linear regression to determine correlation and to describe its effects, logistic regression and receiver operating characteristic curve (ROC curve) to estimate the strength of the relationship between biomarkers and clinical outcomes and value normalization against standard deviation to make biomarker values comparable. Kaplan-Meier estimator and Cox regression models were used to assess survival. Univariate and multivariate models were performed where appropriate.

RESULTS

Multivariate analysis showed that both the amount of total cfDNA (p value = 0.024, HR = 1.199, CI = 1.024-1.405) and the number of CTCs (p value = 0.001, HR = 1.243, CI = 1.088-1.421) are predictors of overall survival (OS), whereas total cfDNA levels is the sole predictor for progression-free survival (PFS) (p value = 0.042, HR = 1.193, CI = 1.007-1.415) and disease response when comparing response to non-response to treatment (HR = 15.917, HR = 12.481 for univariate and multivariate analysis, respectively). Lastly, combined analysis of CTCs and cfDNA is more informative than the combination of two conventional biomarkers (CA15-3 and AP) for prediction of OS.

CONCLUSION

Measurement of total cfDNA levels, which is a simpler and less expensive biomarker than CTC counts, is associated with PFS, OS and response in MBC, suggesting potential clinical application of a cheap and simple blood-based test.

Increased Protein Insolubility in Brains From a Subset of Patients With Schizophrenia

OBJECTIVE

The mechanisms leading to schizophrenia are likely to be diverse. However, there may be common pathophysiological pathways for subtypes of the disease. The authors tested the hypothesis that increased protein insolubility and ubiquitination underlie the pathophysiology for a subtype of schizophrenia.

METHODS

Prefrontal cortex and superior temporal gyrus from postmortem brains of individuals with and without schizophrenia were subjected to cold sarkosyl fractionation, separating proteins into soluble and insoluble fractions. Protein insolubility and ubiquitin levels were quantified for each insoluble fraction, with normalization to total homogenate protein. Mass spectrometry analysis was then performed to identify the protein contents of the insoluble fractions. The potential biological relevance of the detected proteins was assessed using Gene Ontology enrichment analysis and Ingenuity Pathway Analysis.

RESULTS

A subset of the schizophrenia brains showed an increase in protein insolubility and ubiquitination in the insoluble fraction. Mass spectrometry of the insoluble fraction revealed that brains with increased insolubility and ubiquitination exhibited a similar peptide expression by principal component analysis. The proteins that were significantly altered in the insoluble fraction were enriched for pathways relating to axon target recognition as well as nervous system development and function.

CONCLUSIONS

This study suggests a pathological process related to protein insolubility for a subset of patients with schizophrenia. Determining the molecular mechanism of this subtype of schizophrenia could lead to a better understanding of the pathways underlying the clinical phenotype in some patients with major mental illness as well as to improved nosology and identification of novel therapeutic targets.

Novel transcriptional networks regulated by CLOCK in human neurons

Fontenot et al. show that CLOCK regulates the expression of genes involved in neuronal migration. Dysregulation of CLOCK disrupts coexpressed networks of genes implicated in neuropsychiatric disorders, and the expression of these networks is driven by hub genes with human-specific patterns of expression.

The molecular mechanisms underlying human brain evolution are not fully understood; however, previous work suggested that expression of the transcription factor CLOCK in the human cortex might be relevant to human cognition and disease. In this study, we investigated this novel transcriptional role for CLOCK in human neurons by performing chromatin immunoprecipitation sequencing for endogenous CLOCK in adult neocortices and RNA sequencing following CLOCK knockdown in differentiated human neurons in vitro. These data suggested that CLOCK regulates the expression of genes involved in neuronal migration, and a functional assay showed that CLOCK knockdown increased neuronal migratory distance. Furthermore, dysregulation of CLOCK disrupts coexpressed networks of genes implicated in neuropsychiatric disorders, and the expression of these networks is driven by hub genes with human-specific patterns of expression. These data support a role for CLOCK-regulated transcriptional cascades involved in human brain evolution and function.

Diverse Non-genetic, Allele-Specific Expression Effects Shape Genetic Architecture at the Cellular Level in the Mammalian Brain

Interactions between genetic and epigenetic effects shape brain function, behavior, and the risk for mental illness. Random X inactivation and genomic imprinting are epigenetic allelic effects that are well known to influence genetic architecture and disease risk. Less is known about the nature, prevalence, and conservation of other potential epigenetic allelic effects in vivo in the mouse and primate brain. Here we devise genomics, in situ hybridization, and mouse genetics strategies to uncover diverse allelic effects in the brain that are not caused by imprinting or genetic variation. We found allelic effects that are developmental stage and cell type specific, that are prevalent in the neonatal brain, and that cause mosaics of monoallelic brain cells that differentially express wild-type and mutant alleles for heterozygous mutations. Finally, we show that diverse non-genetic allelic effects that impact mental illness risk genes exist in the macaque and human brain. Our findings have potential implications for mammalian brain genetics. VIDEO ABSTRACT.

COMT val158met polymorphism and molecular alterations in the human dorsolateral prefrontal cortex: Differences in controls and in schizophrenia

The single nucleotide val158met polymorphism in catechol o-methyltransferase (COMT) influences prefrontal cortex function. Working memory, dependent on the dorsolateral prefrontal cortex (DLPFC), has been repeatedly shown to be influenced by this COMT polymorphism. The high activity COMT val isoform is associated with lower synaptic dopamine levels. Altered synaptic dopamine levels are expected to lead to molecular adaptations within the synapse and within DLPFC neural circuitry. In this human post mortem study using high quality DLPFC tissue, we first examined the influence of the COMT val158met polymorphism on markers of dopamine neurotransmission, N-methyl-d-aspartate (NMDA) receptor subunits and glutamatic acid decarboxylase 67 (GAD67), all known to be critical to DLPFC circuitry and function. Next, we compared target gene expression profiles in a cohort of control and schizophrenia cases, each characterized by COMT genotype. We find that the COMT val allele in control subjects is associated with significant upregulation of GluN2A and GAD67 mRNA levels compared to met carriers. Comparisons between control and schizophrenia groups reveal that GluN2A, GAD67 and DRD2 are differentially regulated between diagnostic groups in a genotype specific manner. Chronic antipsychotic treatment in rodents did not explain these differences. These data demonstrate an association between COMTval158met genotype and gene expression profile in the DLPFC of controls, possibly adaptations to maintain DLPFC function. In schizophrenia val homozygotes, these adaptations are not seen and could reflect pathophysiologic mechanisms related to the known poorer performance of these subjects on DLPFC-dependent tasks.

Synaptic proteins in the hippocampus indicative of increased neuronal activity in CA3 in schizophrenia

OBJECTIVE

In schizophrenia, hippocampal perfusion is increased and declarative memory function is degraded. Based on an a priori model of hippocampal dysfunction in schizophrenic psychosis, the authors postulated molecular and cellular changes in CA3 consistent with increased NMDA receptor signaling.

METHOD

Postmortem hippocampal subfield tissue (CA3, CA1) from subjects with schizophrenia and nonpsychiatric comparison subjects was analyzed using Western blotting and Golgi histochemistry to examine the hypothesized outcomes.

RESULTS

The GluN2B-containing NMDA receptors (GluN2B/GluN1) and their associated postsynaptic membrane protein PSD95 were both increased in schizophrenia in CA3 tissue, but not in CA1 tissue. Quantitative analyses of Golgi-stained hippocampal neurons showed an increase in spine density on CA3 pyramidal cell apical dendrites (stratum radiatum) and an increase in the number of thorny excrescences.

CONCLUSIONS

The hippocampal data are consistent with increased excitatory signaling in CA3 and/or with an elevation in silent synapses in CA3, a state that may contribute to an increase in long-term potentiation in CA3 with subsequent stimulation and "unsilencing." These changes are plausibly associated with increased associational activity in CA3, with degraded declarative memory function, and with formation of false memories with psychotic content. The influence of these hyperactive hippocampal projections on targets in the limbic neocortex could contribute to components of schizophrenia manifestations in other cerebral regions.

The impact of randomized trial results and altered regulatory policies on ESA use, transfusions, and thrombosis: A longitudinal analysis over a 3-year period of resource utilization data from a large comprehensive oncology program

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Background: Recent randomized trials and meta-analyses demonstrated unexpected findings with ESA use with chemotherapy. Results revealed an overall increase in thrombosis rates with the use of ESAs as well as decrements in survival in some malignancies, particularly with breast and head and neck cancers (Bohlius, JNCI, 2006; Raftopoulos, Proc ASCO, 2008; Bennett, JAMA 2008). Benefits with ESA use have resulted in an average 1–1.5g/dl rise in hemoglobin. The impact on quality of life and fatigue remains controversial. Toxicity issues have led to restricted labeling by the FDA and reimbursement decisions by the Centers for Medicare and Medicaid Services (CMS). Despite these risks associated with the use of ESAs, concerns regarding increased use of transfusions remain prominent. A longitudinal study to assess the impact of these ESA policies was conducted to assess the demand on transfusion services and ESA use over time. Methods: Our center comprises a large comprehensive combined hematology and oncology program and has a non- restrictive transfusion policy, allowing physician discretion and the capacity to accommodate all out-patient transfusions. We analyzed ESA use over the 3 year period, 2006–2008. 2006 functioned as our baseline; 2007 was the year of initial FDA and CMS changes; 2008 allowed us to see if practice changes would persist. Results: We present in the table below, our data on ESA use and transfusion resource utilization. Conclusions: With over 60,000 patient visits during 3 years, longitudinal assessment reveals a continued, marked decrease in ESA use. Despite liberal transfusion policies, there has been little effect on transfusion rates. Increases in transfusions are commensurate with a rise in patient visit volume. We are now evaluating whether this marked decrease in ESA use translates into decreased thrombosis rates over this 3-year period at our cancer center.

[Table: see text]

No significant financial relationships to disclose.

Recombinant erythropoietin (Epo)/darbepoetin (Darb) associated venous thromboembolism (VTE) in the oncology setting: Findings from the Research on Adverse Drug Events And Reports (RADAR) project

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Background: Cancer patients are at increased risk for VTE as compared to the general population, making VTE as a sADR difficult to detect in the oncology setting. In 2004, two phase III trials identified higher mortality rates among epo-treated cancer patients who were receiving chemotherapy in “off-label” settings- with these studies identifying higher VTE rates in the treatment arms. We reviewed data on epo/darb-associated VTE in the oncology setting. Methods: Data sources were meta-analyses and the FDA’s MedWatch database. Results: Since 1996, only 259 VTE reports (darb: n=30, epo: n=229) of VTE in the setting of chemotherapy and epo/darb were reported to MedWatch. Meta-analyses findings are tabulated below: Conclusions: In 2004, package inserts for Epo/Darb were revised, identifying increased risks of VTE with these agents in the oncology setting. Identification of this adverse drug reaction thirteen years after Epo received FDA approval for this indication (and had been prescribed to > 500,000 cancer patients) illustrates difficulties inherent with current pharmacovigilance efforts.

[Table: see text]

No significant financial relationships to disclose.

Clinical trials, case reports, and observational databases as sources of information on serious cancer-related adverse drug reactions (sADRs): Lessons learned from the Research on Adverse Drug Events and Reports (RADAR) project

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Background: Serious adverse drug reactions (sADRs) such as venous thromboembolism resulting from cancer pharmaceutical use are underappreciated and often misattributed to the cancer diagnosis, rather than the therapy. The Research on Adverse Drug events And Reports (RADAR) group evaluated factors associated with identification of serious cancer-related sADRs (i.e. an adverse drug reaction that results in death or severe organ failure). Methods: Information on sources of clinical information, incidence, setting, and time from FDA approval to initial identification was obtained for sADRs that resulted in death or severe organ failure. Most of the ADRs are described as Black Box warnings or in “Dear Doctor” letters. Results: Summarized in table . Conclusion: Clinical trial safety reports from off-label settings facilitate identification of common (>3% rate) cancer associated sADRs. Case reports and observational databases from on-label settings facilitate detection of rare cancer-associated sADRs (<1%) often at lengthy time intervals from initial FDA approval.

No significant financial relationships to disclose.

[Table: see text]

Influence of an algal triacylglycerol containing docosahexaenoic acid (22:6n-3) and docosapentaenoic acid (22:5n-6) on cardiovascular risk factors in healthy men and women

The intake of long-chainn-3 PUFA, including DHA (22:6n-3), is associated with a reduced risk of CVD.Schizochytrium sp.are an important primary source of DHA in the marine food chain but they also provide substantial quantities of then-6 PUFA docosapentaenoic acidn-6; DPA). The effect of this oil on cardiovascular risk factors was evaluated using a double-blind randomised placebo-controlled parallel-design trial in thirty-nine men and forty women. Subjects received 4g oil/d for 4 weeks; the active treatment provided 1·5g DHA and 0·6g DPA. Active treatment increased plasma concentrations of arachidonic acid, adrenic acid, DPA and DHA by 21, 11, 11 and 88mg/l respectively and the proportions of DPA and DHA in erythrocyte phospholipids by 78 and 27% respectively. Serum total, LDL- and HDL-cholesterol increased by 0·33mmol/l (7·3%), 0·26mmol/l (10·4%) and 0·14mmol/l (9·0%) compared with placebo (allp≤0·001). Factor VII (FVII) coagulant activity increased by 12% following active treatment (P=0·006). There were no significant differences between treatments in LDL size, blood pressure, plasma glucose, serum C-reactive protein, plasma FVII antigen, FVII activated, fibrinogen, von Willebrand factor, tocopherol or carotenoid concentrations, plasminogen activator inhibitor-1, creatine kinase or troponin-I activities, haematology or liver function tests or self-reported adverse effects. Overall, the oil was well tolerated and did not adversely affect cardiovascular risk.

Effects of Pulmonary Insufficiency on Biventricular Function in the Developing Heart of Growing Swine

Background— This study was conducted to determine the effects of chronic pulmonary insufficiency (PI) on right (RV) and left (LV) ventricular function in young growing swine.

Methods and Results— Six PI and 5 control animals were studied. PI was induced by transcatheter placement of stents across the pulmonary valve. Indices of systolic function (ejection fraction, cardiac output, and cardiac functional reserve), diastolic function (compliance), and myocardial contractility (the slope of the relationship of end-systolic pressure versus end-systolic volume [E max ] and the slope of the dP/dt max –end-diastolic volume relationship [M dP/dt ]) were assessed within 2 days of intervention and 3 months later. MRI was used to quantify PI and ventricular volumes. Conductance catheter techniques were used to obtain indices of contractility and diastolic compliance from pressure-volume relations at rest and under dobutamine infusion. In the PI group, pulmonary regurgitant fraction was 49.2±5.9% at 3-month follow-up. RV cardiac functional reserve was limited, diastolic function was preserved, and myocardial contractility was altered (E max =2.6±0.3 mm Hg/mL for the PI group versus 3.5±0.4 mm Hg/mL for control; P <0.01). LV cardiac functional reserve was limited, ventricular compliance decreased, and myocardial contractility was preserved.

Conclusions— In the young developing heart, chronic PI alters biventricular systolic function, RV myocardial contractility, and LV diastolic performance.

Endovascular stents in pulmonary valve and artery in swine: feasibility study of MR imaging-guided deployment and postinterventional assessment

PURPOSE

To assess the feasibility of using magnetic resonance (MR) imaging to guide stent deployment in the pulmonary valve and artery and evaluate, after stent deployment, the position and morphology of and blood flow through the stent.

MATERIALS AND METHODS

Angiography and 1.5-T MR imaging were performed in a dual-imaging suite. Nitinol stents were placed in the pulmonary valve and main pulmonary artery in five pigs by using MR imaging guidance. For interactive MR imaging monitoring of catheter manipulation and stent delivery, balanced fast field-echo and T1-weighted turbo field-echo sequences were used. Visualization of the delivery system was based on T2* (with air as the contrast material) or T1 (with gadodiamide as the contrast material). After stent deployment, the position and morphology of and flow through the stent were verified with multiphase multisection balanced fast field-echo and velocity-encoded cine MR imaging. Findings at angiography and postmortem examination also helped verify stent placement. The paired Student t test was used for data analysis.

RESULTS

The stent was successfully deployed in all animals. The stent was placed distal to the pulmonary valve in four animals and across the pulmonary valve in one animal. The position and morphology of the stent were clearly depicted on balanced fast field-echo images. In the animal with the stent placed across the pulmonary valve, the pulmonary regurgitant fraction was 37%; this was not seen in the animals with stents placed distal to the pulmonary valve. No complication (eg, stent migration, intramural injury, or vascular perforation) was noted during the intervention. Findings at angiography and postmortem examination confirmed the position of the stents.

CONCLUSION

MR imaging has the potential to guide stent placement in the pulmonary valve or artery and to evaluate flow volume within the stent lumen after the intervention.

Influence of blood-pool contrast media on MR imaging and flow measurements in the presence of pulmonary arterial stents in swine

PURPOSE

To compare the effects of various stents on magnetic resonance (MR) imaging flow volume measurements and to determine the value of a blood-pool MR imaging contrast medium in assessment of vascular stents.

MATERIALS AND METHODS

In 11 pigs, six nitinol stents (Memotherm), four platinum stents (NuMed), and one elgiloy stent (Wallstent) were placed in the main pulmonary artery under x-ray fluoroscopic guidance. MR imaging was performed 3 months after stent placement before and after injection of NC100150 contrast medium. Blood flow volumes were assessed with velocity-encoded cine MR imaging through and next to the stent. The signal-to-noise ratio and width of susceptibility artifacts of the stents also were determined. Measurements were analyzed with the paired Student t test and Bland-Altman test, where appropriate.

RESULTS

Blood flow volumes measured through the nitinol and platinum stents disclosed no significant difference between velocity-encoded cine MR imaging measurements through and next to the stent. On cine MR images, small susceptibility artifacts were observed around the nitinol and platinum stents. Signal-to-noise ratio in the stent lumen was reduced in nitinol and platinum stents when compared with that next to the stent. The elgiloy stent produced severe susceptibility artifacts, making measurement of flow volumes impossible. NC100150 injection caused no significant effect on flow volume measurements. It improved the signal-to-noise ratio of the pulmonary arterial lumen outside and, to a lesser extent, inside the stent.

CONCLUSION

Assessment of morphology and flow volumes through nitinol and platinum stents is feasible with MR imaging. Blood-pool contrast media provide persistent signal enhancement in the pulmonary artery and, to a lesser extent, in the lumina of nitinol and platinum stents.

Sequential magnetic resonance monitoring of pulmonary flow with endovascular stents placed across the pulmonary valve in growing Swine

BACKGROUND

Patients with endovascular stent implantation for the treatment of right ventricular outflow tract obstruction are often left with incomplete relief of the obstruction and significant pulmonary regurgitation. A noninvasive and reproducible method for monitoring such patients is desirable. MRI in the presence of a stent, however, has to overcome the problem of potential metallic artifacts.

METHODS AND RESULTS

Under x-ray fluoroscopic guidance, endovascular nitinol stents were placed across the pulmonary valve in 6 young pigs to induce pulmonary regurgitation. Five additional pigs served as controls. Initial MRI was performed after 2 days (13.5+/-1.8 kg) and follow-up after 3 months (32+/-2.9 kg). Pulmonary flow volumes and regurgitant fraction were quantified by velocity-encoded cine (VEC) MRI through (VEC-TS) and distal to (VEC-DS) the stent. VEC-TS was compared with VEC-DS and volumetric measurements of left and right ventricular stroke volumes provided by cine MRI ("gold standard"). Antegrade and retrograde pulmonary flow volumes by VEC-TS were slightly but significantly less than those with VEC-DS and cine MRI. Excellent correlations (r>0.97) for phasic pulmonary flow volumes as measured by VEC-TS and VEC-DS were shown. Pulmonary regurgitant fraction increased from 32.8+/-15% to 49.6+/-17% (P<0.05) over the course of 3 months with VEC-TS.

CONCLUSIONS

MRI demonstrates the progression of pulmonary regurgitation in growing swine. VEC MRI has the ability to quantify pulmonary blood flow inside the lumen of nitinol stents. MRI appears to be ideally suited for monitoring patients with endovascular nitinol stents in the pulmonary artery or pulmonary valve position.

Clinical comparison of St. Jude and porcine mitral valve prostheses

One hundred and six consecutive patients who had mitral valve replacement with either a St. Jude or porcine heterograft prosthesis were prospectively studied. The 2 groups are similar with respect to 67 clinical and operative factors and allow comparison of valve performance as an independent variable. Total follow-up is 3,312 patient-months (mean 36 months, range 2-57 months, 94% complete). There are no statistical differences in symptomatic improvement or mortality by life table analysis. Valve-related complications expressed as percent per patient-year are: reoperation: 1.8 St. Jude and 3.8 porcine; endocarditis: 1.2 and 1.9; regurgitant murmur: 2.3 and 1.9; hemolysis: 1.8 and 0.0; late thromboembolism: 1.8 and 1.0; hemorrhage: 2.9 and 2.9; and valve failure: 0.0 and 1.0. There were no significant differences found. Actuarial survival at 3 years was 78% in St. Jude and 81% in porcine patients. Forty-six percent of patients with St. Jude valves and 55% of patients with porcine valves were alive and free of all complications at latest follow-up. The clinical performance of St. Jude and porcine mitral valves are similar over this period of intermediate follow-up.

Familial IgA nephropathy. Evidence of an inherited mechanism of disease

The evaluation of familial glomerulonephritis in patients with IgA nephropathy who were from central and eastern Kentucky resulted in the discovery of potentially related pedigrees containing 14 patients. An additional 17 members of the pedigrees had clinical glomerulonephritis, and 6 had "chronic nephritis" noted on their death certificates. Six patients with IgA nephropathy had a common ancestor. In addition, both parents of six patients with the disease came from families with other cases of IgA nephropathy. No single HLA haplotype or antigen was found in all the patients with IgA nephropathy. Our data on these pedigrees strongly support an inherited mechanism in the pathogenesis of IgA nephropathy in some patients.

T-cell helper circuits

T helper cells specific for trinitrophenylated PC-binding myeloma and hybridoma antibodies are induced by priming with PC antigen, idiotype or anti-idiotypic antibody. These T helper cells are specific for a shared idiotope present on T15 and M167. Priming with the isolated heavy chains of T15 or M167, or the light chain of anti-T15 hybridoma antibody is equally effective in generating T helper cells. Evidently, the idiotope that is recognized by T cells is not dependent upon the conformation of the 7s Ig molecule. Collectively, these and other findings indicate the existence of a TH1-TH2-B cellular circuit which is based on the recognition of idiotopic determinants on T cell receptors. The implications of these findings in terms of network theory are explored.

Idiotype-specific T-helper cells

In the present study we investigated the induction and fine specificity of T-helper cells that recognize idiotypes. The data presented show that both low-dose priming with anti-T15 antiserum and priming with PC-Hy are effective in stimulating T15-specific T help. Phosphorylcholine-hemocyanin priming can generate these T cells in either PC-responding or nonresponding strains of mice. Furthermore, the PC-primed T-helper cells can also recognize another anti-PC myeloma, M167, that is idiotypically different from T15. The fine specificity of the anti-PC-idiotype recognizing T-helper cells was examined by studying the effect of in vitro inhibitors on the T-cell help. Both PC and PC-BSA as well as T15 and M167 had an inhibitory effect on the T help. Free T15 and M167 heavy chains also blocked the helper activity for T15; T15 and M167 light chains had no effect, however. Viewed collectively, these results show that PC-Hy priming induces T-helper cells that recognize idiotypic determinants common to both T15 and M167, and that the proteins' H chain is the major structural component of the determinant. Finally, the generation of these idiotype-recognizing T cells was found to occur by way of a T-T interaction loop, based on the finding that T-helper cells are induced by PC-Hy priming in animals that lack PC-responding B cells.

Regulatory idiotypes. T helper cells recognize a shared VH idiotope on phosphorylcholine-specific antibodies

Priming of BALB/c mice with phosphorylcholine-hemocyanin (PC-Hy) induces T helper cells that are detected in splenic fragment cultures responding to immunization with trinitrophenylated PC-binding myeloma proteins, TEPC 15 (TNP-T15) and MOPC 167 (TNP-M167). Trinitrophenylation did not alter the binding site, idiotype, or isotype of the antibodies as demonstrated by binding studies. To assay idiotype-recognizing helper cells, Ly-2.2-depleted T cells from PC-Hy-primed donor mice were transferred to syngeneic athymic mice. Splenic anti-trinitrophenol fragment cultures were prepared from the nude recipients, and the response to TNP-T15 and TNP-M167 was measured by enzyme-linked immunosorbent assay. The number of responding fragments is dependent on the number of transferred primed T cells. The homing efficiency of 51Cr-labeled helper cells into the spleen of nude recipients was determined. The frequencies of T helper cells taken from PC-Hy-primed donors required for a B cell response to TNP-T15 or TNP-M167 were indistinguishable. The fine specificity of the anti-PC idiotype-recognizing T helper cells was studied by adding hapten (PC) or unconjugated myeloma proteins to fragment cultures as inhibitors at the time of immunization. PC and PC-bovine serum albumin, as well as T15 and M167, inhibited the helper function in vitro. Furthermore, free heavy chains of T15 and M167 partially inhibited T help, but free light chains of both idiotypes had no effect. These findings collectively show that T helper cells, induced by priming with antigen, recognize a shared idiotypic determination on T15 and M167 that is part of the PC binding site. The heavy chains of T15 and M167 appears to be the major structural component of this determinant. Evidently, T helper cells can recognize a shared determinant that is present on idiotypically different myeloma proteins. This determinant appears to be conserved throughout evolutionary and somatic mutations. The role of this shared, binding site-related idiotypic determinant as a regulatory idiotype in T-B cell interaction is discussed.

Balb/c T cells have the potential to recognize the TEPC 15 prototype antibody and its somatic variants

Immunization of BALB/c mice with phosphorylcholine-Limulus polyphemus hemocyanin (PC-Hy) induces a population of T cells that recognize the predominant PC-binding antibody, TEPC15 (T15). The splenic fragment culture system was used to examine the specificity of these T cells for a series of PC-binding myeloma and hybridoma antibodies representing the prototype variable region of the heavy chain (VH)T 15 sequence as well as somatic variants of the T15 germ line-encoded sequence. Included in this group of PC-binding proteins were both T15-positive and T15-negative antibodies, as defined by anti-idiotypic antibody. T cell help was identified by the ability to promote TNP-specific B cell responses to trinitrophenylated PC-binding proteins. It was found that T cells generated by immunization with PC-Hy recognize both antibodies with the T15 prototype sequence and the putative somatic variants of this sequence. A population of these T cells appear to recognize common determinants shared by these proteins because immunization with T15 itself also induces the recognition of the somatic variants. This suggests that idiotopes encoded in the T15 germ line gene expressed by the T15 prototype idiotype and the somatic variants can function as targets for T cell recognition and are thus regulatory idiotopes.

Generation of idiotype-specific T cell help through network perturbation

Different manipulations of BALB/c mice were used to generate idiotype-specific help: neonatally induced suppression of the T 15 idiotype and low-dose priming with anti-T15 antibody. The splenic foci culture system was used to study T15-idiotype-recognizing helper T cells under limiting-cell-dose conditions. These treatments induced T15 idiotype-specific help for B cells responding to TNP-T15. Normal or hemocyanin-primed BALB/c mice did not supply T15 idiotype-specific help. The helper cells were sensitive to anti-Thy-1.2 and complement treatment and can distinguish T15 from an idiotype-different, PC-binding myeloma protein, M167, and the TNP binding myeloma protein, M460. These data show that idiotype-specific T helper cells can be induced by at least two different manipulations of the idiotype network. These manipulations presumably do not act directly on the T15-recognizing T cells, but must involve complementary idiotypic circuits that stimulate anti-T15 specific T cells. Furthermore, this study demonstrates that the splenic-fragment culture technique provides a general method to investigate, at the single cell level, idiotypic T-B cell interactions induced by perturbations of the immune network.