Common conditions of use elements. Atomic concepts for consistent and effective information governance

Myriad policy, ethical and legal considerations underpin the sharing of biological resources, implying the need for standardised and yet flexible ways to digitally represent diverse 'use conditions'. We report a core lexicon of terms that are atomic, non-directional 'concepts of use', called Common Conditions of use Elements. This work engaged biobanks and registries relevant to the European Joint Programme for Rare Diseases and aimed to produce a lexicon that would have generalised utility. Seventy-six concepts were initially identified from diverse real-world settings, and via iterative rounds of deliberation and user-testing these were optimised and condensed down to 20 items. To validate utility, support software and training information was provided to biobanks and registries who were asked to create Sharing Policy Profiles. This succeeded and involved adding standardised directionality and scope annotations to the employed terms. The addition of free-text parameters was also explored. The approach is now being adopted by several real-world projects, enabling this standard to evolve progressively into a universal basis for representing and managing conditions of use.

Getting your DUCs in a row - standardising the representation of Digital Use Conditions

Improving patient care and advancing scientific discovery requires responsible sharing of research data, healthcare records, biosamples, and biomedical resources that must also respect applicable use conditions. Defining a standard to structure and manage these use conditions is a complex and challenging task. This is exemplified by a near unlimited range of asset types, a high variability of applicable conditions, and differing applications at the individual or collective level. Furthermore, the specifics and granularity required are likely to vary depending on the ultimate contexts of use. All these factors confound alignment of institutional missions, funding objectives, regulatory and technical requirements to facilitate effective sharing. The presented work highlights the complexity and diversity of the problem, reviews the current state of the art, and emphasises the need for a flexible and adaptable approach. We propose Digital Use Conditions (DUC) as a framework that addresses these needs by leveraging existing standards, striking a balance between expressiveness versus ambiguity, and considering the breadth of applicable information with their context of use.

Open Data governance at the Canadian Open Neuroscience Platform (CONP): From the Walled Garden to the Arboretum

Scientific research communities pursue dual imperatives in implementing strategies to share their data. These communities attempt to maximize the accessibility of biomedical data for downstream research use, in furtherance of open science objectives. Simultaneously, such communities safeguard the interests of research participants through data stewardship measures and the integration of suitable risk disclosures to the informed consent process. The Canadian Open Neuroscience Platform (CONP) convened an Ethics and Governance Committee composed of experts in bioethics, neuroethics, and law to develop holistic policy tools, organizational approaches, and technological supports to align the open governance of data with ethical and legal norms. The CONP has adopted novel platform governance methods that favor full data openness, legitimated through the use of robust deidentification processes and informed consent practices. The experience of the CONP is articulated as a potential template for other open science efforts to further build upon. This experience highlights informed consent guidance, deidentification practices, ethicolegal metadata, platform-level norms, and commercialization and publication policies as the principal pillars of a practicable approach to the governance of open data. The governance approach adopted by the CONP stands as a viable model for the broader neuroscience and open science communities to adopt for sharing data in full open access.

Reconciling the biomedical data commons and the GDPR: three lessons from the EUCAN ELSI collaboratory

The coming-into-force of the EU General Data Protection Regulation (GDPR) is a watershed moment in the legal recognition of enforceable rights to informational self-determination. The rapid evolution of legal requirements applicable to data use, however, has the potential to outstrip the capabilities of networks of biomedical data users to respond to the shifting norms. It can also delegitimate established institutional bodies that are responsible for assessing and authorising the downstream use of data, including research ethics committees and institutional data custodians. These burdens are especially pronounced for clinical and research networks that are of transnational scale, because the legal compliance burden for outbound international data transfers from the EEA is especially high. Legislatures, courts, and regulators in the EU should therefore implement the following three legal changes. First, the responsibilities of particular actors in a data sharing network should be delimited through the contractual allocation of responsibilities between collaborators. Second, the use of data through secure data processing environments should not trigger the international transfer provisions of the GDPR. Third, the use of federated data analysis methodologies that do not provide analysis nodes or downstream users access to identifiable personal data as part of the outputs of those analyses should not be considered circumstances of joint controllership, nor lead to the users of non-identifiable data to be considered controllers or processors. These small clarifications of, or modifications to, the GDPR would facilitate the exchange of biomedical data amongst clinicians and researchers.

The Deceased, Public Health, and Research: Proposing Legal Reforms

There is little guidance concerning biomedical research using tissues from deceased individuals. Unique ethical and legal challenges gained visibility during the coronavirus disease 2019 (COVID-19) pandemic, when important studies using genome sequencing required access to biological materials from deceased individuals. These studies proposed to determine whether specific genomic profiles were associated with important disease outcomes. Such research has previously required consent from next-of-kin or other surrogate decision makers. Ethics waivers for such consent vary within Canada. In Ontario, research ethics boards can grant waivers of consent if the Tri-Council Policy Statement-2 conditions are met. These include that the individual is not harmed, that the materials are essential to the research, and that privacy will be protected. Conversely, in Quebec, Civil Code article 22 imposes an obligation on researchers to seek consent from next-of-kin or another surrogate decision maker with no option for waivers. It became evident to researchers that these standards can sometimes impose an impracticable balance of risks and benefits, especially in public health emergencies. We seek to establish why and when consent requirements should be waived for public health and research involving the tissues of deceased individuals.

Federated Analysis for Privacy-Preserving Data Sharing: A Technical and Legal Primer

Continued advances in precision medicine rely on the widespread sharing of data that relate human genetic variation to disease. However, data sharing is severely limited by legal, regulatory, and ethical restrictions that safeguard patient privacy. Federated analysis addresses this problem by transferring the code to the data-providing the technical and legal capability to analyze the data within their secure home environment rather than transferring the data to another institution for analysis. This allows researchers to gain new insights from data that cannot be moved, while respecting patient privacy and the data stewards' legal obligations. Because federated analysis is a technical solution to the legal challenges inherent in data sharing, the technology and policy implications must be evaluated together. Here, we summarize the technical approaches to federated analysis and provide a legal analysis of their policy implications.

Open Data in the Era of the GDPR: Lessons from the Human Cell Atlas

The Human Cell Atlas (HCA) is striving to build an open community that is inclusive of all researchers adhering to its principles and as open as possible with respect to data access and use. However, open data sharing can pose certain challenges. For instance, being a global initiative, the HCA must contend with a patchwork of local and regional privacy rules. A notable example is the implementation of the European Union General Data Protection Regulation (GDPR), which caused some concern in the biomedical and genomic data-sharing community. We examine how the HCA's large, international group of researchers is investing tremendous efforts into ensuring appropriate sharing of data. We describe the HCA's objectives and governance, how it defines open data sharing, and ethico-legal challenges encountered early in its development; in particular, we describe the challenges prompted by the GDPR. Finally, we broaden the discussion to address tools and strategies that can be used to address ethical data governance.

The Canadian Open Neuroscience Platform-An open science framework for the neuroscience community

The Canadian Open Neuroscience Platform (CONP) takes a multifaceted approach to enabling open neuroscience, aiming to make research, data, and tools accessible to everyone, with the ultimate objective of accelerating discovery. Its core infrastructure is the CONP Portal, a repository with a decentralized design, where datasets and analysis tools across disparate platforms can be browsed, searched, accessed, and shared in accordance with FAIR principles. Another key piece of CONP infrastructure is NeuroLibre, a preprint server capable of creating and hosting executable and fully reproducible scientific publications that embed text, figures, and code. As part of its holistic approach, the CONP has also constructed frameworks and guidance for ethics and data governance, provided support and developed resources to help train the next generation of neuroscientists, and has fostered and grown an engaged community through outreach and communications. In this manuscript, we provide a high-level overview of this multipronged platform and its vision of lowering the barriers to the practice of open neuroscience and yielding the associated benefits for both individual researchers and the wider community.

The international data governance landscape

As the adoption of digital health accelerates health research increasingly relies on large quantities of biomedical data. Research institutions scattered across a large number of jurisdictions collaborate in producing and analyzing biomedical big data. National data protection legislation, for its part, grows increasingly complex and localized. To respond to heterogeneous legal requirements arising in numerous jurisdictions, decentralized health consortia must develop scalable organizational and 6 technological arrangements that enable data flows across jurisdictional boundaries. In this article, proposals are made to enable health sector organisations to align established biomedical ethics process and data analysis practices to shifting data protection norms through both public law co-regulation, private law tools, and design-oriented approaches.

Computational tools for genomic data de-identification: facilitating data protection law compliance

In this opinion piece, we discuss why computational tools to limit the identifiability of genomic data are a promising avenue for privacy-preservation and legal compliance. Even where these technologies do not eliminate all residual risk of individual identification, the law may still consider such data anonymised.

An agenda-setting paper on data sharing platforms: euCanSHare workshop

Various data sharing platforms are being developed to enhance the sharing of cohort data by addressing the fragmented state of data storage and access systems. However, policy challenges in several domains remain unresolved. The euCanSHare workshop was organized to identify and discuss these challenges and to set the future research agenda. Concerns over the multiplicity and long-term sustainability of platforms, lack of resources, access of commercial parties to medical data, credit and recognition mechanisms in academia and the organization of data access committees are outlined. Within these areas, solutions need to be devised to ensure an optimal functioning of platforms.

GA4GH: International policies and standards for data sharing across genomic research and healthcare

The Global Alliance for Genomics and Health (GA4GH) aims to accelerate biomedical advances by enabling the responsible sharing of clinical and genomic data through both harmonized data aggregation and federated approaches. The decreasing cost of genomic sequencing (along with other genome-wide molecular assays) and increasing evidence of its clinical utility will soon drive the generation of sequence data from tens of millions of humans, with increasing levels of diversity. In this perspective, we present the GA4GH strategies for addressing the major challenges of this data revolution. We describe the GA4GH organization, which is fueled by the development efforts of eight Work Streams and informed by the needs of 24 Driver Projects and other key stakeholders. We present the GA4GH suite of secure, interoperable technical standards and policy frameworks and review the current status of standards, their relevance to key domains of research and clinical care, and future plans of GA4GH. Broad international participation in building, adopting, and deploying GA4GH standards and frameworks will catalyze an unprecedented effort in data sharing that will be critical to advancing genomic medicine and ensuring that all populations can access its benefits.

AI in Cardiovascular Imaging: "Unexplainable" Legal and Ethical Challenges?

Nowhere is the influence of artificial intelligence (AI) likely to be more profoundly felt than in healthcare, from patient triage and diagnosis to surgery and follow-up. Over the medium term, these impacts will be more acute in the cardiovascular imaging context, in which AI models are already successfully performing at roughly human levels of accuracy and efficiency in certain applications. Yet, the adoption of unexplainable AI systems for cardiovascular imaging still raises significant legal and ethical challenges. We focus in particular on challenges posed by the unexplainable character of deep learning and other forms of sophisticated AI modelling used for cardiovascular imaging by briefly outlining the systems being developed in this space, describing how they work, and considering how they might generate outputs that are not reviewable by physicians or system programmers. We suggest that an unexplainable tendency presents two specific ethico-legal concerns: (1) difficulty for health regulators and (2) confusion about the assignment of liability for error or fault in the use of AI systems. We suggest that addressing these concerns is critical for ensuring AI's successful implementation in cardiovascular imaging.

International transfers of personal data for health research following Schrems II: a problem in need of a solution

On 16 July 2020, the Court of Justice of the European Union issued their decision in the Schrems II case concerning Facebook's transfers of personal data from the EU to the US. The decision may have significant effects on the legitimate transfer of personal data for health research purposes from the EU. This article aims: (i) to outline the consequences of the Schrems II decision for the sharing of personal data for health research between the EU and third countries, particularly in the context of the COVID-19 pandemic; and, (ii) to consider certain options available to address the consequences of the decision and to facilitate international data exchange for health research moving forward.

Of Screening, Stratification, and Scores

Technological innovations including risk-stratification algorithms and large databases of longitudinal population health data and genetic data are allowing us to develop a deeper understanding how individual behaviors, characteristics, and genetics are related to health risk. The clinical implementation of risk-stratified screening programmes that utilise risk scores to allocate patients into tiers of health risk is foreseeable in the future. Legal and ethical challenges associated with risk-stratified cancer care must, however, be addressed. Obtaining access to the rich health data that are required to perform risk-stratification, ensuring equitable access to risk-stratified care, ensuring that algorithms that perform risk-scoring are representative of human genetic diversity, and determining the appropriate follow-up to be provided to stratification participants to alert them to changes in their risk score are among the principal ethical and legal challenges. Accounting for the great burden that regulatory requirements could impose on access to risk-scoring technologies is another critical consideration.

Longitudinal Health Studies: Secondary Uses Serving the Future

Our research compares the ethical and institutional conditions that govern the sharing and secondary use of longitudinal population health data from multiple cohorts. The data use and data sharing conditions applicable to 27 population health cohorts were assessed. This assessment was performed in consulting the informed consent materials and institutional policies applicable to the use of data. Descriptions drawn from the research ethics consent materials were refined through dialog with the institutional staff responsible for overseeing access to data, where possible. Our results demonstrate that data of longitudinal population health cohorts assessed can generally be shared and used for secondary purposes. However, the purposes of secondary use and the preconditions applicable thereto are highly variable. Heterogeneous use conditions can also impede the storage of legacy research data and the pooling thereof for the purpose of common reuse.

Radical collaboration during a global health emergency: development of the RDA COVID-19 data sharing recommendations and guidelines

Background: The coronavirus disease 2019 (COVID-19) global pandemic required a rapid and effective response. This included ethical and legally appropriate sharing of data. The European Commission (EC) called upon the Research Data Alliance (RDA) to recruit experts worldwide to quickly develop recommendations and guidelines for COVID-related data sharing. Purpose: The purpose of the present work was to explore how the RDA succeeded in engaging the participation of its community of scientists in a rapid response to the EC request. Methods: A survey questionnaire was developed and distributed among RDA COVID-19 work group members. A mixed-methods approach was used for analysis of the survey data. Results: The three constructs of radical collaboration (inclusiveness, distributed digital practices, productive and sustainable collaboration) were found to be well supported in both the quantitative and qualitative analyses of the survey data. Other social factors, such as motivation and group identity were also found to be important to the success of this extreme collaborative effort. Conclusions: Recommendations and suggestions for future work were formulated for consideration by the RDA to strengthen effective expert collaboration and interdisciplinary efforts.

Fostering global data sharing: highlighting the recommendations of the Research Data Alliance COVID-19 working group

The systemic challenges of the COVID-19 pandemic require cross-disciplinary collaboration in a global and timely fashion. Such collaboration needs open research practices and the sharing of research outputs, such as data and code, thereby facilitating research and research reproducibility and timely collaboration beyond borders. The Research Data Alliance COVID-19 Working Group recently published a set of recommendations and guidelines on data sharing and related best practices for COVID-19 research. These guidelines include recommendations for clinicians, researchers, policy- and decision-makers, funders, publishers, public health experts, disaster preparedness and response experts, infrastructure providers from the perspective of different domains (Clinical Medicine, Omics, Epidemiology, Social Sciences, Community Participation, Indigenous Peoples, Research Software, Legal and Ethical Considerations), and other potential users. These guidelines include recommendations for researchers, policymakers, funders, publishers and infrastructure providers from the perspective of different domains (Clinical Medicine, Omics, Epidemiology, Social Sciences, Community Participation, Indigenous Peoples, Research Software, Legal and Ethical Considerations). Several overarching themes have emerged from this document such as the need to balance the creation of data adherent to FAIR principles (findable, accessible, interoperable and reusable), with the need for quick data release; the use of trustworthy research data repositories; the use of well-annotated data with meaningful metadata; and practices of documenting methods and software. The resulting document marks an unprecedented cross-disciplinary, cross-sectoral, and cross-jurisdictional effort authored by over 160 experts from around the globe. This letter summarises key points of the Recommendations and Guidelines, highlights the relevant findings, shines a spotlight on the process, and suggests how these developments can be leveraged by the wider scientific community.

Fostering global data sharing: highlighting the recommendations of the Research Data Alliance COVID-19 working group

The systemic challenges of the COVID-19 pandemic require cross-disciplinary collaboration in a global and timely fashion. Such collaboration needs open research practices and the sharing of research outputs, such as data and code, thereby facilitating research and research reproducibility and timely collaboration beyond borders. The Research Data Alliance COVID-19 Working Group recently published a set of recommendations and guidelines on data sharing and related best practices for COVID-19 research. These guidelines include recommendations for researchers, policymakers, funders, publishers and infrastructure providers from the perspective of different domains (Clinical Medicine, Omics, Epidemiology, Social Sciences, Community Participation, Indigenous Peoples, Research Software, Legal and Ethical Considerations). Several overarching themes have emerged from this document such as the need to balance the creation of data adherent to FAIR principles (findable, accessible, interoperable and reusable), with the need for quick data release; the use of trustworthy research data repositories; the use of well-annotated data with meaningful metadata; and practices of documenting methods and software. The resulting document marks an unprecedented cross-disciplinary, cross-sectoral, and cross-jurisdictional effort authored by over 160 experts from around the globe. This letter summarises key points of the Recommendations and Guidelines, highlights the relevant findings, shines a spotlight on the process, and suggests how these developments can be leveraged by the wider scientific community.

Correction to: Pandemics, privacy, and public health research

In the section entitled "Responsive and responsible data sharing,".

Pandemics, privacy, and public health research

Sharing data expediently for pandemic response purposes exposes healthcare providers in Canada to significant regulatory uncertainty. Duplicative and contradictory ethical and legal duties flowing from overlapping sources can stifle flows of medical data among clinicians, researchers, and institutions. Authorities should support caregivers and accelerate research by providing clear guidance to the health sector. Institutions should foster robust data stewardship and standardize their practices to those recognized among the international health informatics community. Reform is critical to ensuring Canadian healthcare providers can deliver efficient health responses that are integrated with dispersed and disparate national and international approaches.

Rare disease data stewardship in Canada

The Canadian Genomics Partnership for Rare Diseases, spearheaded by Genome Canada, will integrate genome-wide sequencing to rare disease clinical care in Canada. Centralized and tiered models of data stewardship are proposed to ensure that the data generated can be shared for secondary clinical, research, and quality assurance purposes in compliance with ethics and law. The principal ethico-legal obligations of clinicians, researchers, and institutions are synthesized. Governance infrastructures such as registered access platforms, data access compliance offices, and Beacon systems are proposed as potential organizational and technical foundations of responsible rare disease data sharing. The appropriate delegation of responsibilities, the transparent communication of rights and duties, and the integration of data privacy safeguards into infrastructure design are proposed as the cornerstones of rare disease data stewardship.

Survey of delivery of prophylactic immunoglobulins following exposure to a measles case

In France, almost 23,000 cases of measles and 10 deaths have been reported between January 2008 and August 2012. French health authorities recommend delivery of human polyvalent immunoglobulins in the event of exposure to a measles case for some categories of unvaccinated persons (children under the age of 12 months, immunocompromised persons and pregnant women), within six days after exposure and following laboratory confirmation of the contact case. We carried out a postal survey among 368 French hospital pharmacies to evaluate the number of persons affected by this measure between 1 January 2010 and 31 August 2011, to describe the characteristics of these patients and to evaluate the application of the recommendations in terms of delay between exposure and immunoglobulin delivery, and confirmation of the contact case. The response rate to the survey was 73%. In total, 400 immunoglobulin deliveries were listed, most of them for children under the age of one year, and 84% of the 250 administrations with available information occurred within six days after exposure, as recommended. However, only 48% of the 209 treated contacts with available information were laboratory-confirmed when the immunoglobulins were delivered. This survey is the first evaluation of this recommendation since its introduction in 2005 and suggests that the recommendations may need to be updated.

Validation of a high-performance liquid chromatographic assay for the quantification of adenovirus type 5 particles

An anion-exchange-high-performance liquid chromatography (AE-HPLC) method for the quantification of adenovirus type 5 (Ad5) total particles was validated according to performance criteria of precision, specificity, linearity of calibration and range, limit of detection, limit of quantification, accuracy and recovery. The viral particles were detected by absorbance at 260 nm using photodiode array detector (PDA). Cesium chloride (CsCl) purified Ad5 and lysate samples were used for the validation of the method. Relative standard deviations (RSDs) for the inter-day, intra-day precision and reproducibility for both the lysate and the Ad5 standard were less than 10 and 2% for the peak area and retention time, respectively. The method was specific for Ad5 which was eluted at 8.0 min. The presence of DNA does not affect the recovery of Ad5 particles for accurate quantification. Based on the error in prediction to be less than 10%, the working range was established between 2 x 10(10) and 7 x 10(10) VP/ml with correlation coefficient of 0.99975, standard deviation of 6.14 x 10(9) VP/ml and a slope of 3.04 x 10(5) VP/ml. The recovery of the method varied between 88 and 106% in all of the lysate samples investigated which is statistically similar to 100% recovery at 95% confidence interval.

Improved high-performance liquid chromatographic method in the analysis of adenovirus particles

We developed a HPLC method on a novel continuous bed matrix (UNO Q, Bio-Rad) for the direct quantification of adenoviral type 5 (Ad5) particles produced in 293S Human Embryonic Kidney cells and compared this with an existing HPLC method on a conventional ion-exchange resin (Resource Q, Pharmacia). The 293S cell extract contained large amounts of DNA. This contaminated the viral peak on the Resource Q column and only after Benzonase treatment was it possible to quantify the viral particles in the cell extract. In contrast, the virus peak on the UNO Q column was resolved from the DNA which eliminates the need for pretreatment of the sample with Benzonase. Cross-analysis of the Ad5 fraction from the UNO Q column using a size-exclusion HPLC column revealed no additional contaminating peaks. We conclude that the purity of the Ad5 virus peak on the continuous bed matrix UNO Q column was superior to the purity of the virus on the conventional Resource Q column, which is essential for reliable quantification.

Social support processes: mediators of attachment state of mind and adjustment in late adolescence

This study examined the mediational link between attachment state of mind, social support processes and personal adjustment. The Adult Attachment Interview was administered to 62 adolescents during their college transition. At the end of high school and during their first semester in college, students completed questionnaires pertaining to primary and secondary appraisals; coping and personal adjustment were assessed through self- and peer-report questionnaires. A dismissing tendency was related to difficulty in getting assistance from peers and teachers and to peer-reported withdrawal. A preoccupied tendency was associated with stress regarding the transition, distrust in potential supporters, difficulty seeking help from teachers, and loneliness. Moreover, stress, distrust and help-seeking mediated the link between preoccupied attachment and loneliness, whereas the relation between dismissing attachment and withdrawal was not mediated by help-seeking. Cognitive and behavioral attachment processes are discussed.

Gonadotrophin storage patterns in the ewe during the oestrous cycle or after long-term treatment with a GnRH agonist

The storage pattern of gonadotrophins in the ewe pituitary was investigated during the oestrous cycle and after desensitization to GnRH using long-term treatment with a GnRH agonist, buserelin. Oestrous cycles in ewes were synchronized with progestagen sponges. Animals were allocated to two experiments. In the first, ewes were killed 36 h (before the preovulatory surge, n = 4), 48 h (end of the preovulatory surge, n = 5), 72 h (post-ovulation, n = 4) and 240 h (luteal phase, n = 3) after sponge removal. In the second experiment, another progestagen sponge was inserted in ewes 84 h after removal of the first sponge. Four ewes were infused continuously with buserelin (50 micrograms/day) for 15 days before killing. A further four ewes received no buserelin (controls). Pituitaries were collected and processed for immunocytochemistry to detect monohormonal (LH or FSH) and multihormonal (LH/FSH) cells. The percentages of LH or FSH immunoreactive cells in the pituitary were lower at the end of the preovulatory surge (7.4 +/- 0.3% and 1.2 +/- 0.3% respectively) compared with the other stages (11.4 +/- 0.5% and 5.4 +/- 0.7% respectively). Analysis of dual immunostaining showed the existence of monohormonal cells for LH and multihormonal cells (LH/FSH). No monohormonal cell for FSH was detected except at the end of the preovulatory surge when a few monohormonal FSH cells appeared (0.1 +/- 0.01% of pituitary cells). The percentage of monohormonal LH cells in the pituitary gland was similar in all studied stages of the oestrous cycle, whereas the percentage of multihormonal cells was lower at the end of the surge. In agonist-treated ewes, the percentages of LH or FSH immunoreactive cells (5.3 +/- 0.5% and 1.5 +/- 0.8% respectively) were decreased compared with controls (9.4 +/- 1% and 7.5 +/- 1.1% respectively). Analysis of the double immunostaining revealed a few monohormonal FSH cells (0.2 +/- 0.01% of pituitary cells) in agonist-treated ewes but not in controls. The percentage of monohormonal LH cells in the pituitary gland increased from 1.9 +/- 0.2% in controls to 3.8 +/- 0.3% in agonist-treated ewes, whereas multihormonal cells dropped from 7.5 +/- 1.1% to 1.3 +/- 0.7%. Our data suggest, therefore, that multihormonal cells contribute to gonadotrophin secretion, either during the preovulatory surge of the oestrous cycle or during the 'flare-up' effect initially induced by a GnRH agonist. Moreover, the appearance of monohormonal FSH cells in some conditions reflects a differential regulation of LH and FSH.

Aortic percutaneous transluminal valvuloplasty in elderly patients by balloon larger than aortic anulus

Twenty-four elderly patients (79 +/- 7 years) with long-standing calcified aortic stenosis have been divided in two comparable groups of 12. The first group was treated with 19 mm balloon percutaneous transluminal valvuloplasty, where the balloon diameter was always smaller than the aortic anulus diameter. Peak-to-peak aortic valve gradient decreased from 76 +/- 32 mmHg to 30 +/- 19 (P less than .05), and the aortic valve area, calculated by Gorlin formula, increased from 0.40 +/- 0.17 cm2 to 0.57 +/- 0.17 (P less than .05). The second group was treated with a trefoil 25 mm balloon, always larger than the aortic anulus diameter. In this second group, peak-to-peak aortic valve gradient decreased from 73 +/- 34 mmHg to 23 +/- 15 (P less than .05), and aortic valve area increased from 0.47 +/- 0.14 cm2 to 0.88 +/- 0.36 (P less than .05), increasing thus more than in group I (P less than .05). Clinical tolerance to balloon inflation was not the same according to individual patients but was similar between the two groups; complications were comparable in the two groups. These results suggest that aortic valvuloplasty by trefoil balloon larger than aortic anulus can provide wider aortic valve area without increasing complication rate.

A General Method of Four-Bar Linkage Mobility Analysis

The problem of mobility associated with four-bar linkages is addressed in this paper. The mobility analysis is reduced to finding the global extrema of a quadratic function on a cylinder, which then leads to the geometric problem of finding the intersections of a circle and a hyperbola. The method proposed here produces an efficient mobility analysis that can be readily integrated into any suitable optimization algorithm.

Opening snap and isovolumic relaxation period in relation to mitral valve flow in patients with mitral stenosis. Significance of A2--OS interval

In 15 patients with pure or predominant mitral stenosis and in a control group of 11 patients without mitral stenosis the blood flow velocity through the mitral valve orifice was recorded by means of a directional Doppler ultrasound velocity catheter introduced transeptally and positioned in the orifice of the mitral valve. A simultaneous surface phonocardiogram was obtained. The timing of the mitral opening snap in relation to the blood velocity record of the flow through the valve supported the hypothesis that the opening snap is due to a sudden tensing of the valve leaflets by the chordae tendineae. Determination of the exact time of mitral valve opening, made possible by the blood velocity record, led to the division of the classical A2-0S interval (aortic valve closure to opening snap) into two components representing respectively the diastolic isovolumic relaxation period and the time of excursion of the mitral valve cusps. The durations of the isovolumic relaxation period were compared with those in the control patients and were found to correlate with the severity of the mitral stenosis, whereas those of the excursion time of the mitral cusps were influenced by the presence or absence of mitral valve calcification.

Diagnosis and evaluation of mitral valve disease using transseptal Doppler ultrasound catheterization

In 33 patients with confirmed mitral valve disease, the mitral valve flow velocity traces were recorded by means of a directional Doppler ultrasonic velocimeter using the transseptal route, and correlated with the clinical and haemodynamic data. In all cases, characteristic anomalies of the mitral flow velocity patterns were noted and could be related to the type of lesion, stenosis, regurgitation, or a combination of these. Furthermore, specific patterns of the flow velocity traces were shown to correlate satisfactorily with the degree of severity of the disease. The authors propose a pathophysiological interpretation of the anomalies of the velocity patterns, based on turbulence for stenosis and backward flow wave for regurgitation. They conclude that the transseptal directional Doppler catheterization provides a new reliable method for establishing the diagnosis and grading the severity of mitral valve disease using pattern recognition, and, moreover, offers a new approach to the understanding of mitral haemodynamic disturbances on a beat-to-beat basis.

Normal pattern and physiological significance of mitral valve flow velocity recorded using transseptal directional Doppler ultrasound catheterization

In 10 cardiac patients in whom an organic lesion of the mitral valve was exluded by standard investigation procedures during which a diagnostic transseptal catheterization for pressure measurements in the left heart was performed, the authors placed a directional Doppler ultrasonic catheter tip velocimeter at the site of the mitral ring and recorded the mitral flow velocity traces. The pattern of these normal curves is presented and a physiological interpretation proposed. The relation between the mitral flow velocity and low volume curves is discussed in the light of present experimental data on mitral valve flow velocity profiles and variations in size of the mitral orifice. The authors concluded that the flow velocity curves obtained by the Doppler technique constitute a valid physiological reference system for the study of the mitral valve flow velocity tracings that can be recorded in the various forms of mitral valve disease.

SYPHILITIC ULCERATIONS WITH THE HISTOLOGICAL PICTURE OF A PRICKLE CARCINOMA CURED BY ANTI-LUETIC TREATMENT

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