Comparison of peer-assisted learning with expert-led learning in medical school ultrasound education: a systematic review and meta-analysis

INTRODUCTION

Teaching point-of-care ultrasonography (PoCUS) to medical students is resource intensive. Peer-assisted learning, where the teacher can be a medical student, may be a feasible alternative to expert-led learning. The objective of this systematic review and meta-analysis was to compare the PoCUS performance assessments of medical students receiving peer-assisted vs expert-led learning.

METHODS

This study was submitted to PROSPERO (CRD42023383915) and reported with PRISMA guidelines. MEDLINE, Embase, ERIC, Education Source, Scopus, and Web of Science were searched from inception to November 2022. Inclusion criteria were studies comparing peer-assisted vs expert-led PoCUS teaching for undergraduate medical students. The primary outcome was performance assessment of PoCUS skills. Two reviewers independently screened citations and extracted data. The Cochrane risk-of-bias tool for randomized trials was used to assess study quality. Studies were included in the meta-analysis if mean performance assessment scores with standard deviations and sample sizes were available. A random-effects meta-analysis was conducted to estimate the accuracy score of practical knowledge test for each group. A meta-regression evaluated difference in mean scores.

RESULTS

The search yielded 2890 citations; 1417 unique citations remained after removing duplicates. Nine randomized-controlled studies conducted in Germany, USA, and Israel, with 593 participants, were included in the meta-analysis. The included studies assessed teaching of abdominal, cardiac, thoracic, musculoskeletal, and ocular PoCUS skills. Most studies had some risk-of-bias concerns. The estimate accuracy score after weighting is 0.56 (95% CI [0.47, 0.65]) for peer-assisted learning and 0.59 (95% CI [0.49, 0.69]) for expert-led learning. The regression coefficient estimate is 0.0281 (95% CI [- 0.1121, 0.1683]); P value is 0.69.

CONCLUSION

This meta-analysis found that peer-assisted learning was a reasonable alternative to expert-led learning for teaching PoCUS skills to medical students.

Prevalence of patient partner authorship and acknowledgment in child health research publications: an umbrella review

OBJECTIVES

Children and families are increasingly involved as equal partners in child health research, however, considerations around authorship have received little attention and there is limited guidance on the topic. Our objective was to determine the frequency and nature of patient partner authorship and/or acknowledgment among articles focused on patient engagement in child health research.

STUDY DESIGN AND SETTING

In this umbrella review, we searched MEDLINE, Embase, APA PsycINFO, Cochrane Database of Systematic Reviews, CINAHL, and Web of Science for systematic/scoping reviews on patient engagement in child health research. Individual articles included in eligible reviews comprised the sample of articles for analysis and were examined to identify patient partner authorship. Descriptive statistics were used to quantify patient partner authorship and/or acknowledgment and to summarize article characteristics.

RESULTS

Twelve systematic/scoping reviews met eligibility criteria, from which 230 individual articles were examined. In 16/230 (7%) articles, there was at least one patient partner author, and in 6/230 (3%) articles, patient partners were included as group authors. Within article Acknowledgments sections, patient partners were acknowledged by name in 41/230 (18%) articles, and anonymously or as a group in 98/230 (43%) articles. Patient partner authorship and/or acknowledgment was more frequent among articles published more recently (after 2015) and among articles where patient engagement was explicitly reported in the article.

CONCLUSION

Patient partners were more likely to be acknowledged than listed as an author on articles on patient engagement in child health research. Understanding patient partner preferences about authorship and acknowledgment, examination of the unique aspects of child and youth authorship and developing supports to empower patient partner authorship are needed.

Combinatorial Effect of Biomaterials and Extracellular Vesicle Therapy for Heart Failure with Reduced Ejection Fraction: A Systematic Review of Preclinical Studies

Heart failure, a pervasive global health burden, necessitates innovative therapeutic strategies. Extracellular vesicles (EVs) have emerged as promising contenders for cardiac repair, owing to their profound influence on fibrosis and inflammation. Merging EVs with biomaterials holds the potential for a synergistic leap in therapeutic efficacy. In this review, the impact of combining EVs with biomaterials in preclinical heart failure models is scrutinized. Fifteen studies, predominantly employing mesenchymal stromal cell-derived EVs along with hyaluronic acid or peptides in coronary ligation models, meet these stringent criteria. The amalgamation of EVs and biomaterials consistently enhances cardiac ejection fraction (1.39; 95% CI: 0.68, 2.11; p = 0.0001) and fractional shortening (1.46, 95% CI: 0.70, 2.22; p = 0.0002) compared to EV monotherapy. Secondary outcomes similarly showcased improvement in the combined treatment group. Although the number of studies analyzed is modest, no indications of publication bias surface. In summary, combination therapy with EVs and biomaterials enhances therapeutic benefit in preclinical heart failure models. The consistent improvement observed across diverse EV sources, biomaterials, and animal models underscores the exciting potential of this synergistic approach.

A scoping review protocol on diagnostic strategies to detect occult malignancies in individuals with ischemic stroke

BACKGROUND

Emerging data show an increased risk of ischemic stroke in patients with a new diagnosis of cancer. As the risk of stroke begins to increase 150 days before cancer is diagnosed, stroke may be the first clinical manifestation of undiagnosed cancer. About 6% of patients with cryptogenic ischemic stroke (unknown etiology after diagnostic evaluations) are diagnosed with cancer within one year. However, the optimal cancer screening strategy in this population is not known. We aim to conduct a scoping review of screening strategies for occult cancer in individuals with ischemic stroke.

METHODS

Electronic databases including MEDLINE (Ovid), EMBASE (Ovid), CINAHL (EBSCOhost) and Scopus will be systematically searched to identify articles that report on screening strategies for occult cancer in individuals with ischemic stroke. At least two investigators will independently perform two-stage study selection consisting of title/abstract screening and full-text review, followed by data extraction. Thereafter, a thematic analysis will be conducted to provide an overview of what diagnostic tests/strategies have been used, and their clinical utility in terms of positive and negative predictive value (when available).

CONCLUSION

We anticipate that the findings of this scoping review will identify strategies used to detect occult cancer in individuals with ischemic stroke and summarize their clinical utility (if reported). Addressing this knowledge gap will help guide the development of future clinical trials on occult cancer screening patients with ischemic stroke.

Impact of coaching on physician wellness: A systematic review

Physician wellness is critical for patient safety and quality of care. Coaching has been successfully and widely applied across many industries to enhance well-being but has only recently been considered for physicians. This review aimed to summarize the existing evidence on the effect of coaching by trained coaches on physician well-being, distress and burnout. MEDLINE, Embase, ERIC, PsycINFO and Web of Science were searched without language restrictions to December 21, 2022. Studies of any design were included if they involved physicians of any specialty undergoing coaching by trained coaches and assessed at least one measure along the wellness continuum. Pairs of independent reviewers determined reference eligibility. Risk of bias was assessed using the Cochrane Risk of Bias Tools for Randomized Controlled Trials (RCTs) and for Non-randomized Studies of Interventions (ROBINS-I). Meta-analysis was not possible due to heterogeneity in study design and outcome measures as well as inconsistent reporting. The search retrieved 2531 references, of which 14 were included (5 RCTs, 2 non-randomized controlled studies, 4 before-and-after studies, 2 mixed-methods studies, 1 qualitative study). There were 1099 participants across all included studies. Risk of bias was moderate or serious for non-RCTs, while the 5 RCTs were of lower risk. All quantitative studies reported effectiveness of coaching for at least one outcome assessed. The included qualitative study reported a perceived positive impact of coaching by participants. Evidence from available RCTs suggests coaching for physicians can improve well-being and reduce distress/burnout. Non-randomized interventional studies have similar findings but face many limitations. Consistent reporting and standardized outcome measures are needed.

The Impact of Patient and Family Engagement in Child Health Research: A Scoping Review

OBJECTIVE

To identify impacts of patient and family engagement in child health research on the research process, research teams, and patient and family partners.

STUDY DESIGN

A scoping review was conducted using the MEDLINE, Embase, Cumulative Index to Nursing and Allied Health Literature, PsycINFO, and Web of Science databases. English-language studies were included if they described ≥1 impact of patient and family engagement on child health research (age <18 years), researchers, or patient and family partners. Data were retrieved by 2 independent extractors.

RESULTS

Of the 7688 studies identified, 25 were included in our analysis. Impacts of patient and family engagement were mostly on the research process (n = 24 studies; 96%), 11 (44%) determined impacts on the research team, and 17 (68%) reported impacts on patient and family partners. Less than one-half (n = 11; 44%) had a primary purpose of determining the impact of patient engagement, and no study used a specific evaluation tool.

CONCLUSIONS

Patient and family engagement can strengthen the relevance and feasibility of research and empower researchers and patient partners. Measuring and reporting the impact of engagement is rare. Systematic and standardized evaluation of engagement is needed to understand how, when, and why to engage patients and families.

Changes in the Library Landscape Regarding Visible Minority Librarians in Canada

Objective – As a follow-up to the first 2013 survey, the Visible Minority Librarians of Canada (ViMLoC) network conducted its second comprehensive survey in 2021. The 2021 survey gathered detailed information about the demography, education, and employment of visible minority librarians (VMLs) working in Canadian institutions. Data from the 2021 survey and the analysis presented in this paper help us better understand the current library landscape, presented alongside findings from the 2013 survey. The research results will be helpful for professional associations and library administrators to develop initiatives to support VMLs. Methods – Researchers created online survey questionnaires using Qualtrics XM in English and translated them into French. We distributed the survey invitation through relevant library association electronic mail lists and posted on ViMLoC’s website, social networking platforms, and through their electronic mail list. The survey asked if the participant was a visible minority librarian. If the response was “No,” the survey closed. Respondents indicating "Yes" were asked 36 personal and professional questions of three types: multiple-choice, yes/no, and open-ended questions. Results – One hundred and sixty-two VMLs completed the 2021 survey. Chinese remained the largest ethnic identity, but their proportion in the survey decreased from 36% in 2013 to 24% in 2021. 65% were aged between 26 and 45 years old. More than half received their library degree during the 2010s. 89% completed their library degree in Canada, a 5% increase from 2013. The majority of librarians had graduated from University of Toronto (25%), followed closely by University of British Columbia (23%), and Western University (22%). Only 3% received their library degree from a library school outside North America. 34% of librarians earned a second master’s degree and 5% had a PhD. 60% of librarians had less than 11 years of experience. Nearly half worked in academic libraries. Most were located in Ontario and British Columbia. 69% of librarians were in non-management positions with 5% being senior administrators. 25% reported a salary above $100,000. In terms of job categories, the largest group worked in Reference/Information Services (45%), followed by Instruction Services (32%), and as Liaison Librarians (31%). Those working in Acquisitions/Collection Development saw the biggest jump from 1% in 2013 to 28% in 2021. 58% of librarians sought mentoring support, of whom 54% participated in formal mentorship programs, and 48% had a visible minority mentor. Conclusion – 35% more VMLs responded to the 2021 survey compared to the 2013 survey. Changes occurred in ethnic identity, generation, where VMLs earned a Master of Library and Information Science (MLIS) or equivalent degree, library type, geographic location, and job responsibilities. The 2021 survey also explored other aspects of the VMLs not covered in the 2013 survey, such as librarian experience, salary, management positions, and mentorship experience. The findings suggested that the professional associations and library administrators would need collaborative efforts to support VMLs.

All-cause mortality after major gastrointestinal bleeding among patients receiving direct oral anticoagulants: a protocol for a systematic review and meta-analysis

BACKGROUND

Gastrointestinal (GI) bleeding represents the single most frequent site of anticoagulant-related bleeding. Adverse outcomes after major GI bleeding including mortality are not well characterized and, as a result, may be underappreciated in clinical practice. We aim to conduct a systematic review and meta-analysis of the risk for 30-day all-cause mortality after major GI bleeding among patients receiving DOACs.

METHODS

Electronic databases including MEDLINE, EMBASE, and Cochrane CENTRAL will be systematically searched to identify randomized controlled trials and prospective and retrospective cohort studies reporting 30-day all-cause mortality in adults with DOAC-related major GI bleeding. At least two investigators will independently perform study selection, risk of bias assessment, and data extraction. The proportion of deaths following a major GI event relative to the number of major GI bleeding events will be calculated for each individual study, and results across studies will be pooled using random-effects meta-analysis. We will assess risk of bias using criteria proposed by the GRADE group for prognostic studies.

DISCUSSION

The findings of this systematic review and meta-analysis will provide clinicians and patients with estimates of mortality after the most common major bleeding event to support shared decision making about anticoagulation management.

TRIAL REGISTRATION

PROSPERO CRD42022295815.

Legal concerns in health-related artificial intelligence: a scoping review protocol

BACKGROUND

Medical innovations offer tremendous hope. Yet, similar innovations in governance (law, policy, ethics) are likely necessary if society is to realize medical innovations' fruits and avoid their pitfalls. As innovations in artificial intelligence (AI) advance at a rapid pace, scholars across multiple disciplines are articulating concerns in health-related AI that likely require legal responses to ensure the requisite balance. These scholarly perspectives may provide critical insights into the most pressing challenges that will help shape and advance future regulatory reforms. Yet, to the best of our knowledge, there is no comprehensive summary of the literature examining legal concerns in relation to health-related AI. We thus aim to summarize and map the literature examining legal concerns in health-related AI using a scoping review approach.

METHODS

The scoping review framework developed by (J Soc Res Methodol 8:19-32, 2005) and extended by (Implement Sci 5:69, 2010) and the Preferred Reporting Items for Systematic Reviews and Meta-Analysis extension for scoping reviews (PRISMA-ScR) guided our protocol development. In close consultation with trained librarians, we will develop a highly sensitive search for MEDLINE® (OVID) and adapt it for multiple databases designed to comprehensively capture texts in law, medicine, nursing, pharmacy, other healthcare professions (e.g., dentistry, nutrition), public health, computer science, and engineering. English- and French-language records will be included if they examine health-related AI, describe or prioritize a legal concern in health-related AI or propose a solution thereto, and were published in 2012 or later. Eligibility assessment will be conducted independently and in duplicate at all review stages. Coded data will be analyzed along themes and stratified across discipline-specific literatures.

DISCUSSION

This first-of-its-kind scoping review will summarize available literature examining, documenting, or prioritizing legal concerns in health-related AI to advance law and policy reform(s). The review may also reveal discipline-specific concerns, priorities, and proposed solutions to the concerns. It will thereby identify priority areas that should be the focus of future reforms and regulatory options available to stakeholders in reform processes.

TRIAL REGISTRATION

This protocol was submitted to the Open Science Foundation registration database. See https://osf.io/zav7w .

A homozygous canonical splice acceptor site mutation in PRUNE1 is responsible for a rare childhood neurodegenerative disease in Manitoba Cree families

Autosomal recessive PRUNE1 mutations are reported to cause a severe neurodevelopmental disorder with microcephaly, hypotonia, and brain malformations. We describe clinical and neuropathological features in a cohort of nine individuals of Cree descent who, because of a founder effect, are homozygous for the same PRUNE1 mutation. They follow the course of a combined neuromuscular and neurodegenerative disease, rather than a pure failure of normal development. This cohort presented in infancy with features of lower motor neuron disease, such as hypotonia, contractures, tongue fasciculations, and feeding difficulties in the absence of congenital brain anomalies and microcephaly. A neurodegenerative course followed with onset of seizures, spasticity, and respiratory insufficiency. Muscle biopsies showed denervation/reinnervation features, nonspecific atrophy and end-stage atrophy. Autopsy findings in two patients are also described, suggesting length dependent central motor axon degeneration, peripheral motor axon degeneration, possible spinal motor neuron degeneration, and accumulation of beta amyloid precursor protein inclusions in select brainstem nuclei. Exome sequencing and homozygosity mapping identified a homozygous PRUNE1 mutation in a canonical splice site, which produces two abnormal PRUNE1 mRNA products. Based on our studies and the histopathology and phenotypic data, we provide further evidence that this disorder leads to a neurodegenerative disease affecting both the peripheral and central nervous systems and suggest that the pathogenic c.521-2A>G mutation could lead to an altered effect on tubulin dynamics.

Assessment of Multilingual Collections in Public Libraries: A Case Study of the Toronto Public Library

Abstract Objective – The Toronto Public Library has been frequently identified as having an exemplary multilingual collection to serve the information needs of the most diverse population in Canada; however, there is no evidence or collection assessment information available in the literature to validate those claims. This research sought to gain an understanding of the current state of their multilingual collection and compare it to the most recent multicultural population demographics. Methods – This was a case study of the Toronto Public Library multilingual collection using data collected from their online public access catalogue in November 2017. Data was collected about all languages available, with English, French, and the 17 most spoken mother tongues explored in more detail. Language results from the Statistics Canada 2016 Census of Population were also collected. Data was used to calculate and compare the English, French, and language collections to the population of reported mother tongues spoken in Toronto. Results – It was found that the Toronto Public Library has items in 307 languages. While the collection comprises many languages, there is far more focus on official language items than any other language compared to the population in terms of number of items and variety of formats. All 17 non-official languages that were studied had fewer items proportionally available in the catalogue than the proportion of speakers with that mother tongue. Conclusion – The high circulation rates of the Toronto Public Library’s multilingual collection indicate that it has had some success in meeting the needs of its community. However, as the largest library system in Canada with a highly regarded multilingual collection and with many resources for collection development, the Toronto Public Library falls short of having a language collection that is proportional to the languages spoken within the community. While it may not be possible to have a multilingual collection that is entirely representative of the community, this study shows that libraries can use census data to monitor population shifts in order to be responsive to the information needs of their changing communities.

Light and COP1 regulate level of overexpressed DET1 protein

de-etiolated 1 (det1) and constitutive photomorphogenic 1 (cop1) were initially identified as constitutively photomorphogenic Arabidopsis mutants, exhibiting light-grown phenotypes in the dark. Subsequently, both were shown to be components of Damaged DNA Binding protein 1 (DDB1)/CULLIN4-type complexes. Arabidopsis has two DDB1 homologues, DDB1A and DDB1B, and DDB1A mutants enhance det1 phenotypes. Here we examine ddb1a cop1 double mutants and find that ddb1a weakly enhances some cop1 phenotypes but not others, suggesting developmental regulation of COP1-DDB1A interaction. DET1 loss of function strongly enhances cop1 phenotypes. Here we show that MycDET1 overexpression also enhances cop1 phenotypes, thus MycDET1 overexpression in cop1 mutants also generates loss of function effects. Finally, the effect of the cop1 mutant background on the biochemical properties of MycDET1 was examined. MycDET1 levels were found to be lower in the dark than in the light and this difference required COP1. In summary, both DDB1A loss of function and MycDET1 overexpression enhance cop1 phenotypes, while cop1 mutants fail to exhibit light regulation of MycDET1 levels.

Interactions between Arabidopsis DNA repair genes UVH6, DDB1A, and DDB2 during abiotic stress tolerance and floral development

Plants must protect themselves from a spectrum of abiotic stresses. For example, the sun is a source of heat, intense light, and DNA-damaging ultraviolet (UV) rays. Damaged DNA binding protein 1A (DDB1A), DDB2, and UV hypersensitive 6 (UVH6)/XPD are all involved in the repair of UV-damaged DNA - DDB1A and DDB2 in the initial damage recognition stage, while the UVH6/XPD helicase unwinds the damaged strand. We find that, as predicted, Arabidopsis ddb1a and ddb2 mutants do not affect uvh6/xpd UV tolerance. In addition, uvh6 is heat sensitive, and ddb1a and ddb2 weakly enhance this trait. The uvh6 ddb1a and uvh6 ddb2 double mutants also exhibit sensitivity to oxidative stress, suggesting a role for DDB1 complexes in heat and oxidative stress tolerance. Finally, we describe a new uvh6 phenotype, the low penetrance production of flowers with five petals and five sepals. ddb1a and ddb2 suppress this phenotype in uvh6 mutants. Interestingly, heat treatment also induces five-petalled flowers in the ddb1a and ddb2 single mutants. Thus UVH6, DDB1A, and DDB2 all contribute to UV tolerance, heat tolerance and floral patterning.

A novel mutation in KIAA0196: identification of a gene involved in Ritscher-Schinzel/3C syndrome in a First Nations cohort

BACKGROUND

Ritscher-Schinzel syndrome (RSS) is a clinically heterogeneous disorder characterised by distinctive craniofacial features in addition to cerebellar and cardiac anomalies. It has been described in different populations and is presumed to follow autosomal recessive inheritance. In an effort to identify the underlying genetic cause of RSS, affected individuals from a First Nations (FN) community in northern Manitoba, Canada, were enrolled in this study.

METHODS

Homozygosity mapping by SNP array and Sanger sequencing of the candidate genes in a 1Mb interval on chromosome 8q24.13 were performed on genomic DNA from eight FN RSS patients, eight of their parents and five unaffected individuals (control subjects) from this geographic isolate.

RESULTS

All eight patients were homozygous for a novel splice site mutation in KIAA0196. RNA analysis revealed an approximate eightfold reduction in the relative amount of a KIAA0196 transcript lacking exon 27. A 60% reduction in the amount of strumpellin protein was observed on western blot.

CONCLUSIONS

We have identified a mutation in KIAA0196 as the cause of the form of RSS characterised in our cohort. The ubiquitous expression and highly conserved nature of strumpellin, the product of KIAA0196, is consistent with the complex and multisystem nature of this disorder.

Early detection of denervated muscle fibers in hindlimb muscles after sciatic nerve transection in wild type mice and in the G93A mouse model of amyotrophic lateral sclerosis

The cell adhesion molecule N-CAM is localized to the adult neuromuscular junction but is also expressed in the extrajunctional membrane of denervated muscles concurrent with extrajunctional acetylcholine receptors. Here we used N-CAM immunohistochemistry to determine whether we could detect early denervation in hindlimb muscles of the G93A transgenic mouse model of amyotrophic lateral sclerosis (ALS). In denervated wild type mouse muscles, N-CAM immunoreactivity on the sarcolemma of all fiber types and within the sarcoplasm of only type IIA fibers was detected at day 2: approximately 30% of the muscle fibers in cross-section were fully circumscribed by N-CAM immunoreactivity and approximately 25% of fibers were incompletely circumscribed. The proportion of the latter fibers remained constant over the next 8 days as the proportions of the former fibers increased exponentially. Thereafter, fully circumscribed muscle fibers increased to a maximum by 30 days with a concomitant fall in the incompletely circumscribed fibers. Hence, early muscle denervation was detected by the incomplete circumscription of fiber membranes by N-CAM immunoreactivity with full circumscription and intracellular localization indicating more long-term denervation. In the G93A transgenic mouse, rapid denervation of fast-twitch muscles was readily detected by a corresponding proportion of muscle fibers in cross-section with positive N-CAM immunoreactivity. The proportions of incompletely and completely circumscribed muscle fibers corresponded well with the rate of decline in intact motor units and reduced muscle contractile forces. Progressively more fully circumscribed muscle fibers became evident with age. We conclude that the N-CAM immunoreactivity on muscle fiber membranes in muscle cross-sections provides a sensitive means of detecting early muscle fiber denervation.

[Frequency of G6PD deficiency in a group of preschool-aged children in a centrally located area of Cambodia]

The aim of this study was to determine the frequency of G6PD deficiency and assess its impact on morbidity, especially anemia, in preschool-aged children in Cambodia. A total of 151 children including 82 boys and 69 girls from the Kandal province near Phnom Penh were studied. Ages ranged from 8 to 69 months. Blood was collected in EDTA-coated tubes. Blood counts were performed with an ABX Micros 60 system and G6PD in red blood cells was measured with a Roche Cobas Mira Plus system using Gamma reagents. G6PD deficiency was found in 14 cases (13.4% of boys and 4.3% of girls). Deficiency was complete in 7.3% of children and partial in 2%. Anemia defined as hemoglobin concentration less than 110 g/l was detected in 29.1% of children. No case of anemia could be attributed to enzyme deficiency since no sign of hemolysis was observed in any of the three children presenting both conditions. Further study is needed on G6PD deficiency in Cambodia including malaria-endemic areas and on the frequency and severity of jaundice due to enzyme deficiency in newborns.

Antinucleic acid autoantibody responses of normal human origin: antigen specificity and idiotypic characteristics compared to patients with systemic lupus erythematosus and patients with monoclonal IgM

One idiotype family 4.6.3 derived from a human hybridoma IgML monoclonal anti-DNA antibody of normal origin is commonly expressed (approximately 85%) in the serum of patients with systemic lupus erythematosus but not in normal controls, where its level appears to fluctuate with clinical disease activity. In contrast, the IgM released by normal cultured lymphocytes in vitro expresses this idiotype family but does not bind DNA. Both idiotype 4.6.3 and anti-DNA antibodies are frequently detectable in the serum of patients with monoclonal IgM but not IgG. Therefore, it is likely that idiotype 4.6.3 reflects the expression of a common germ line immunoglobulin gene family. Some of the IgM molecules encoded by these germ line immunoglobulin genes also bind DNA.