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Competing Interests: Disclosures Glen Gejerman reports being a consultant for Palette Life Sciences. Michael Chao reports being a consultant for Palette Life Sciences. John Lederer reports being a consultant for Palette Life Sciences. John Sylvester reports being a stock owner in C4 and a consultant for Boston Scientific, Theragenics Corporation, and Myriad. Peter Orio reports being a consultant for Palette Life Sciences and Theragenics Corporation.

Competing Interests: The authors declare no competing interest.

The Earth BioGenome Project (EBP) is an audacious endeavor to obtain whole-genome sequences of representatives from all eukaryotic species on Earth. In addition to the project's technical and organizational challenges, it also faces complicated ethical, legal, and social issues. This paper, from members of the EBP's Ethical, Legal, and Social Issues (ELSI) Committee, catalogs these ELSI concerns arising from EBP. These include legal issues, such as sample collection and permitting; the applicability of international treaties, such as the Convention on Biological Diversity and the Nagoya Protocol; intellectual property; sample accessioning; and biosecurity and ethical issues, such as sampling from the territories of Indigenous peoples and local communities, the protection of endangered species, and cross-border collections, among several others. We also comment on the intersection of digital sequence information and data rights. More broadly, this list of ethical, legal, and social issues for large-scale genomic sequencing projects may be useful in the consideration of ethical frameworks for future projects. While we do not-and cannot-provide simple, overarching solutions for all the issues raised here, we conclude our perspective by beginning to chart a path forward for EBP's work., Competing Interests: The authors declare no competing interest., (Copyright © 2022 the Author(s). Published by PNAS.)

Drawing on a landscape analysis of existing data-sharing initiatives, in-depth interviews with expert stakeholders, and public deliberations with community advisory panels across the U.S., we describe features of the evolving medical information commons (MIC). We identify participant-centricity and trustworthiness as the most important features of an MIC and discuss the implications for those seeking to create a sustainable, useful, and widely available collection of linked resources for research and other purposes.

Increasing our understanding of Earth's biodiversity and responsibly stewarding its resources are among the most crucial scientific and social challenges of the new millennium. These challenges require fundamental new knowledge of the organization, evolution, functions, and interactions among millions of the planet's organisms. Herein, we present a perspective on the Earth BioGenome Project (EBP), a moonshot for biology that aims to sequence, catalog, and characterize the genomes of all of Earth's eukaryotic biodiversity over a period of 10 years. The outcomes of the EBP will inform a broad range of major issues facing humanity, such as the impact of climate change on biodiversity, the conservation of endangered species and ecosystems, and the preservation and enhancement of ecosystem services. We describe hurdles that the project faces, including data-sharing policies that ensure a permanent, freely available resource for future scientific discovery while respecting access and benefit sharing guidelines of the Nagoya Protocol. We also describe scientific and organizational challenges in executing such an ambitious project, and the structure proposed to achieve the project's goals. The far-reaching potential benefits of creating an open digital repository of genomic information for life on Earth can be realized only by a coordinated international effort., Competing Interests: The authors declare no conflict of interest.

National and international public-private partnerships, consortia, and government initiatives are underway to collect and share genomic, personal, and healthcare data on a massive scale. Ideally, these efforts will contribute to the creation of a medical information commons (MIC), a comprehensive data resource that is widely available for both research and clinical uses. Stakeholder participation is essential in clarifying goals, deepening understanding of areas of complexity, and addressing long-standing policy concerns such as privacy and security and data ownership. This article describes eight core principles proposed by a diverse group of expert stakeholders to guide the formation of a successful, sustainable MIC. These principles promote formation of an ethically sound, inclusive, participant-centric MIC and provide a framework for advancing the policy response to data-sharing opportunities and challenges.

Discussions surrounding patient engagement and empowerment often use the terms "patient" and "consumer" interchangeably. But do the two terms hold the same meaning, or is a "patient" a passive actor in the health care arena and a "consumer" an informed, rational decision-maker? Has there been a shift in our usage of the two terms that aligns with the increasing commercialization of health care in the U.S. or has the patient/consumer dynamic always been a part of the buying and selling of health care in the American system? Recent discussions of the issue exist in the popular press and in social media forums such as TEDMED, but few direct analyses of the ethical, legal, and policy ramifications of this possible shift in terminology are available in the academic literature. This paper analyzes our usage of the terms and any recent changes in the dynamic and discusses the ethical, legal, and policy implications of this simple terminology for the physicianpatient relationship., (© 2015 American Society of Law, Medicine & Ethics, Inc.)

Electronic health records and electronic health information exchange are essential to improving quality of care, reducing medical errors and health disparities, and advancing the delivery of patient-centered medical care. In the US correctional setting, these goals are critical because of the high numbers of Americans affected, yet the use of health information technology is quite limited. In this article, I describe the legal environment surrounding health information sharing in corrections by focusing on 2 key federal privacy laws: the Health Insurance Portability and Accountability Act of 1996 and the federal Confidentiality of Alcohol and Drug Abuse Patient Records laws. In addition, I review stakeholder concerns and describe possible ways forward that enable electronic exchange while ensuring protection of inmate information and legal compliance.

We review the evolution of federal financing for child health care over the past 40 years. The Social Security Amendments of 1967 established the program of early and periodic screening, diagnosis and treatment (EPSDT) as a required Medicaid benefit. The EPSDT amendments directed agencies to cover "early and periodic" screening and diagnostic services to ascertain "defects" and "chronic conditions" in children, as well as health care and treatment needed to "correct or ameliorate" such defects and conditions discovered during the screening examinations. The 1997 enactment of the Children's Health Insurance Program (CHIP) shifted federal policy from the use of an early coverage standard to one that gives insurers much more discretion to define medical necessity and coverage exclusions. CHIP programs offer coverage that is narrower than the benefits available under Medicaid. The Affordable Care Act (ACA) requires significantly more classes of care to be covered than does CHIP but well below the level of coverage under Medicaid. Implementation of the ACA to date suggests that the US Department of Health and Human Services will only demand pediatric coverage pegged to the commercial insurance market standards, rather than Medicaid's unique pediatric coverage standard. Although EPSDT's emphasis on early, developmental, and ameliorative services might result in more comprehensive benefits for children, particularly those with special health needs, one might still describe the ACA coverage as providing a basic, minimal level of services from a distributive justice perspective. It may, however, vary from state to state. States have the authority to decide whether to use an EPSDT-style approach or to follow the more restrictive approach of commercial insurance plans. Advocacy at the state level will determine which approach different states take.

During this early stage of HIT adoption, it is critical that we engage in discussions regarding informed consent's proper role in a health care environment in which electronic information sharing holds primary importance. This article discusses current implementation of the doctrine within health information exchange networks; the relationship between informed consent and privacy; the variety of ways that the concept is referenced in discussions of information sharing; and challenges that surround incorporation of the doctrine into the evolving HIT environment. The article concludes by reviewing the purpose behind the traditional obligation to obtain informed consent and the possibility of maintaining its relevance in the new environment.

The widespread adoption of health information technology (HIT) has been recognized as both a necessary element of health reform and a required building block of a modern, high performing health care system.

Carney complex (CNC) is a familial multiple neoplasia syndrome characterized by cardiac and extracardiac myxomas in the setting of spotty skin pigmentation and endocrinopathy. We previously identified PRKAR1A (regulatory subunit 1alpha of protein kinase A) mutations in CNC. Mutational analyses of the PRKAR1A gene in 51 unrelated CNC probands now detect mutations in 65%. All mutations, except for one unique missense mutation, lead to PRKAR1A haploinsufficiency. Therefore, we studied the consequences of prkar1a haploinsufficiency in mice. Although we did not observe cardiac myxomas or altered pigmentation in prkar1a(+/-) mice, we did observe some phenotypes similar to CNC, including altered heart rate variability. Moreover, prkar1a(+/-) mice exhibited a marked propensity for extracardiac tumorigenesis. They developed sarcomas and hepatocellular carcinomas. Sarcomas were frequently associated with myxomatous differentiation. Tumors from prkar1a(+/-) mice did not exhibit prkar1a loss of heterozygosity. Thus, we conclude that although PRKAR1A haploinsufficiency does predispose to tumorigenesis, distinct secondary genetic events are required for tumor formation.

Transcriptional regulatory cascades during epicardial and coronary vascular development from proepicardial progenitor cells remain to be defined. We have used immunohistochemistry of human embryonic tissues to demonstrate that the TBX5 transcription factor is expressed not only in the myocardium, but also throughout the embryonic epicardium and coronary vasculature. TBX5 is not expressed in other human fetal vascular beds. Furthermore, immunohistochemical analyses of human embryonic tissues reveals that unlike their epicardial counterparts, delaminating epicardial-derived cells do not express TBX5 as they migrate through the subepicardium before undergoing epithelial-mesenchymal transformation required for coronary vasculogenesis. In the chick, Tbx5 is expressed in the embryonic proepicardial organ (PEO), which is composed of the epicardial and coronary vascular progenitor cells. Retrovirus-mediated overexpression of human TBX5 inhibits cell incorporation of infected proepicardial cells into the nascent chick epicardium and coronary vasculature. TBX5 overexpression as well as antisense-mediated knockdown of chick Tbx5 produce a cell-autonomous defect in the PEO that prevents proepicardial cell migration. Thus, both increasing and decreasing Tbx5 dosage impairs development of the proepicardium. Culture of explanted PEOs demonstrates that untreated chick proepicardial cells downregulate Tbx5 expression during cell migration. Therefore, we propose that Tbx5 participates in regulation of proepicardial cell migration, a critical event in the establishment of the epicardium and coronary vasculature.

Purpose: We reviewed and contrast with the literature the cumulative clinical experience at our pediatric urological division in the last 20 years with managing testicular torsion, focusing specifically on the direction and degree of testicular torsion and the duration of symptoms before presentation. We also addressed the incidence of gastrointestinal symptoms, role of manual detorsion, residual torsion and incidence of atrophy., Materials and Methods: We reviewed the medical records of 200 consecutive males 18 months to 20 years old who underwent surgical exploration by a pediatric urologist for a diagnosis of testicular torsion between 1980 and 2000., Results: Of 186 nonelective explorations symptoms were localized to the left side in 52% and to the right side in 48%. Information on the direction and degree of testicular rotation was available in 162 of 186 cases (87%) and anticipated medial rotation occurred in only 108 (67%). Lateral rotation in 54 of 162 cases (33%) occurred in 28 of 84 (33%) with left torsion and in 26 of 78 (33%) with right torsion. A median of 540 degrees of torsion (range 180 to 1,080) was noted in the 70 orchiectomy cases (38%) and a median of 360 degrees (range 180 to 1,080) was noted in the 116 salvaged testes (62%). Manual detorsion was attempted in 53 orchiopexy cases with residual torsion in 17 (32%). Testicular atrophy developed in 27% of the patients., Conclusions: The traditional teaching that testicular torsion occurs primarily in the medial direction is misleading since in a third of cases it occurs in the lateral direction. While manual detorsion should be guided by response and return of normal anatomy, surgical exploration remains necessary since residual torsion still poses a risk to testicular viability. Long-term followup is warranted to assess the true incidence of subsequent atrophy after the management of acute testicular torsion.

Mutations in human TBX5, a member of the T-box transcription factor gene family, cause congenital cardiac septation defects and isomerism in autosomal dominant Holt-Oram syndrome. To determine the cellular function of TBX5 in cardiogenesis, we overexpressed wild-type and mutant human TBX5 isoforms in vitro and in vivo. TBX5 inhibited cell proliferation of D17 canine osteosarcoma cells and MEQC quail cardiomyocyte-like cells in vitro. Mutagenesis of the 5' end of the T-box but not the 3' end of the T-box abolished this effect. Overexpression of TBX5 in embryonic chick hearts showed that TBX5 inhibits myocardial growth and trabeculation. TBX5 effects in vivo were abolished by Gly80Arg missense mutation of the 5' end of the T-box. PCNA analysis in transgenic chick hearts revealed that TBX5 overexpression does suppress embryonic cardiomyocyte proliferation in vivo. Inhibitory effects of TBX5 on cardiomyocyte proliferation include a noncell autonomous process in vitro and in vivo. TBX5 inhibited proliferation of both nontransgenic cells cocultured with transgenic cells in vitro and nontransgenic cardiomyocytes in transgenic chick hearts with mosaic expression of TBX5 in vivo. Immunohistochemical studies of human embryonic tissues, including hearts, also demonstrated that TBX5 expression is inversely related to cellular proliferation. We propose that TBX5 can act as a cellular arrest signal during vertebrate cardiogenesis and thereby participate in modulation of cardiac growth and development., (Copyright 2001 Academic Press.)

Mutations in the TBX5 transcription factor gene cause human cardiac malformation in Holt-Oram syndrome. To identify and localize TBX5 during cardiac morphogenesis, we performed immunohistochemical studies of TBX5 protein cardiac expression during human embryogenesis. Specific antibody to human TBX5 was generated in rabbits with a TBX5 synthetic peptide and affinity purification of antiserum. Anti-TBX5 was used in immunohistochemical analyses of human cardiac tissue. In embryonic and adult heart, TBX5 is expressed throughout the epicardium and in cardiomyocyte nuclei in myocardium of all four cardiac chambers. Endocardial expression of TBX5 is only present in left ventricle. Asymmetric left-sided transmyocardial gradients of TBX5 protein expression were observed in embryonic but not adult hearts. Human cardiac expression of TBX5 protein correlates with the cardiac manifestations of Holt-Oram syndrome. TBX5 transmyocardial protein gradients may contribute to normal patterning of the human heart during embryogenesis., (Copyright 2000 Wiley-Liss, Inc.)

Cardiac lipomas occur infrequently but account for a significant portion of rare cardiac tumors. Common cutaneous lipomas have previously been associated with rearrangements of chromosome band 12q15, which often disrupt the high-mobility-group protein gene HMGIC. In this report, we describe the cytogenetic analysis of an unusual giant cardiac lipoma that exhibited myocardial invasion in a patient with a history of multiple lipomatosis (cutaneous lipoma, lipomatous gynecomastia, lipomatous hypertrophy of the interatrial septum, and dyslipidemia). Cytogenetic studies of cells derived from the cardiac lipoma demonstrated no abnormalities of chromosome 12, but did reveal a t(2;19)(p13;p13.2). A liposarcoma-derived oncogene (p115-RhoGEF) previously mapped to chromosome 19 and the low-density lipoprotein receptor gene (LDLR) previously mapped to chromosome band 19p13 were evaluated to determine whether they were disrupted by this translocation. Fluorescence in situ hybridization analyses assigned p115-RhoGEF to chromosome 19 in bands q13.2-q13.3 and mapped the LDLR to chromosome arm 19p in segment 13.2, but centromeric to the t(2;19) breakpoint. Thus, these genes are unlikely to be involved in the t(2;19)(p13;p13.2). Further studies of the regions of chromosomes 2 and 19 perturbed by the translocation in this unusual infiltrating cardiac lipoma will identify gene(s) that participate in adipocyte growth and differentiation and may provide insight into syndromes of multiple lipomatosis.

To generate an in vivo system for investigating the postintegration phase of HIV-1 replication, mouse lines transgenic for a full-length infectious proviral clone of a monocyte-tropic HIV-1 isolate, HIV-1JR-CSF, were constructed. Leukocytes from two independent JR-CSF transgenic mouse lines produced HIV-1 that infected human PBMCs. Plasma viremia was detected in these mice at levels (mean, >60,000 HIV RNA copies/ml) comparable to those reported for HIV-1-infected individuals. The levels of HIV RNA in these mice increased several-fold after either treatment with the superantigen Staphylococcus enterotoxin B or infection with Mycobacterium tuberculosis. Thus, a provirus encoding a monocyte-tropic HIV-1 strain under the control of its LTR expressed as a transgene in mice can proceed through the postintegration replication phase and produce infectious virus. In addition, the presence of plasma viremia that can be monitored by measuring plasma HIV-1 RNA levels permits these mice to be used to study the impact of different interventions on modulating in vivo HIV-1 production. Therefore, these mice provide a novel manipulable system to investigate the in vivo regulation of HIV-1 production by factors that activate the immune system. Furthermore, this murine system should be useful in delineating the role of human-specific factors in modulating HIV-1 replication and investigating the in vivo therapeutic efficacy of agents that target the postintegration stages of HIV-1 replication.

We describe an individual in whom molecular genetic testing provided a diagnosis of the Carney complex, an autosomal dominant syndrome comprising cutaneous and cardiac myxomas, spotty pigmentation of the skin, and endocrinopathy. Recently, we localized the Carney complex disease gene to chromosome region 17q2. Our patient was a member of a family segregating the Carney complex, but was not, himself, initially thought to be affected. Haplotype analysis based on genotyping studies with 17q2 microsatellites predicted that this individual was, in fact, affected by Carney complex and was at risk for development of myxomas. Further clinical evaluation and re-review of prior pathologic studies, then, confirmed the DNA-based diagnosis. This report highlights the difficulty in establishing a diagnosis of Carney complex based on clinical and pathologic findings alone, and we suggest that molecular genetic analyses provide an important diagnostic method for this familial myxoma syndrome., (Copyright 1999 Wiley-Liss, Inc.)

Immunoproliferative small intestinal disease (IPSID) is a subtype of lymphoma of mucosa-associated lymphoid tissue. Notable for a high production of alpha-heavy chains, it is designated alpha-heavy-chain disease. IPSID is a debilitating disease that has a predilection for impoverished populations of developing countries. It has been documented primarily in subjects of Middle Eastern countries and thus was previously referred to as Mediterranean lymphoma. We report the case of a 42-year-old man from Senegal who presented with chronic diarrhea, dehydration, and weight loss. The endoscopic, pathologic, and serologic findings before, during, and after treatment with fludarabine phosphate are presented. We review the literature concerning current concepts on the etiology, pathogenesis, and management of IPSID.

Checkout recommendations for anesthesia apparatus are promoted as a means of improving patient safety. We sought to determine residents' performance of institutional checkout procedures and the degree of their improvement after instructional video review. Twenty-nine residents performing a list of pre-use checkout procedures were videotaped (VT1) prior to randomization into a Control or Test group. The Control group had a second videotaping (VT2), whereas the Test group received instructional review of VT1 prior to VT2. Control and Test subjects then had instructional review of all tapes. A blinded investigator scored all tapes without interacting with any subject. Control and Test video scores were compared at VT1 and VT2 using analysis of variance. Differences were sought between the clinical anesthesia (CA) 1-, 2-, and 3-yr residents. Percent "perfect," "partial," or "no" completion of each criterion was calculated to determine performance and improvement. A low-performance rate of 69% (20.6/30) occurred in VT1, significantly improving to 81% (24.2/30) in the Test group after intervention (P < 0.0021) with significant reductions in criteria that were totally missed. Anesthesia apparatus checkout procedures are improved after intensive training sessions, although high rates of completion are not achieved. This performance deficit may have implications for the ability of physicians to detect anesthesia machine faults.

IL-12, a cytokine produced by macrophages and B cells, has recently been found to exert pleiotropic effects on the immune system. When BALB/c mice, a strain highly susceptible to virulent Mycobacterium tuberculosis infection, were given IL-12 at the initiation of infection with M. tuberculosis, their mean survival time doubled from 58 to 112 days. IL-12-treated mice had diminished bacterial burdens, whereas treatment with exogenous IFN-gamma had no effect on survival or bacterial burden. IL-12 treatment also delayed lung pathology in BALB/c mice. In contrast with the findings in the BALB/c model, IL-12 did not increase survival of M. tuberculosis-infected gko mice, transgenic mice in which the IFN-gamma gene has been disrupted, indicating that IL-12 does not induce protection against tuberculosis in mice in the absence of IFN-gamma.

Understanding the immunological mechanisms of protection and pathogenesis in tuberculosis remains problematic. We have examined the extent to which tumor necrosis factor-alpha (TNF alpha) contributes to this disease using murine models in which the action of TNF alpha is inhibited. TNF alpha was neutralized in vivo by monoclonal antibody; in addition, a mouse strain with a disruption in the gene for the 55 kDa TNF receptor was used. The data from both models established that TNF alpha and the 55 kDa TNF receptor are essential for protection against tuberculosis in mice, and for reactive nitrogen production by macrophages early in infection. Granulomas were formed in equal numbers in control and experimental mice, but necrosis was observed only in mice deficient in TNF alpha or TNF receptor. TNF alpha and the 55 kDa TNF receptor are necessary conditions for protection against murine M. tuberculosis infection, but are not solely responsible for the tissue damage observed.

We have recently developed a modified SCID-hu mouse model in which the implanted human thymus and liver (hu-thy/liv) and human peripheral T cells become infected with HIV-1 after i.p. inoculation. By using this model, we evaluated the effect of HIV-1 infection on thymic maturation and observed that different HIV-1 strains had divergent effects of thymic maturation. Although minimal effects on continued thymopoiesis in the hu-thy/liv implant were observed after chronic infection with two primary patient isolates, HIV-1(28) and HIV-1(59), and with HIV-1ADA, HIV-1Ba-L, HIV-1JR-CSF, HIV-1JR-FL, and HIV-1SF162, significant thymocyte depletion was detected after infection with HIV-1IIIB and HIV-1RF. Thus, the effect of HIV-1 infection on thymocyte maturation may depend upon the strain of HIV-1 infecting the thymus. Despite the minimal effects on thymopoiesis observed in the hu-thy/liv implanted in SCID-hu mice 6 mo after infection with HIV-1(28), significant changes were seen in the human T cell population circulating in the peripheral blood of these mice. These changes ranged from an inversion of the CD4/CD8 ratio of peripheral human T cells in some SCID-hu mice to the almost complete depletion of peripheral human T cells observed in other SCID-hu mice. Because these effects were associated with the detection of HIV-1 infection of the peripheral human T cells, these modified SCID-hu mice should prove to be a valuable model for investigating the effects of chronic HIV-1 infection on the peripheral human T cell population.

To determine whether the human thymus provides an environment for the maturation of murine T cells, human fetal thymus and liver (hu-thy/liv) were implanted into congenitally athymic NIH-beige-nude-xid (BNX) mice or C.B-17 scid/scid (SCID) mice. 3 mo after implantation, in contrast to the hu-thy/liv implant in SCID mice, which was populated only with human CD4/CD8 single- and double-positive thymocytes, the hu-thy/liv implant in BNX mice contained a chimeric population of human and mouse CD4/CD8 single- and double-positive thymocytes. Immunohistochemical staining of the hu-thy/liv implant in BNX mice indicated that the population of double-positive mouse thymocytes was localized to discrete areas of the human fetal thymus. Quantitative improvements in mouse T cell and immunoglobulin (Ig) G parameters were observed after grafting of the human fetal thymus and liver tissue into BNX mice. In addition, in contrast to the nonimplanted BNX mice, the implanted BNX mice were capable of mounting a keyhole limpet hemocyanin-specific IgG response and their peripheral T cells were responsive to stimulation with mitogens and antibodies directed to the T cell receptor. Furthermore, after in vivo priming, T cells present in lymph nodes of the implanted BNX mice were capable of mounting an antigen-induced in vitro T cell-dependent proliferative response. Thus, concurrent with the continued maturation of human T cells, murine T cells differentiated within the human fetal thymus implanted in the BNX mice and mediated the phenotypic and functional reconstitution of the murine immune system. Mice with a reconstituted immune system that contain a human thymic implant that is infectible with human immunodeficiency virus (HIV) should prove useful in the investigation of T cell maturation in the thymus and in the evaluation of potential HIV vaccines.

Mice with a targeted disruption in the beta 2-microglobulin (beta 2m) gene, which lack major histocompatibility complex class I molecules and consequently fail to develop functional CD8 T cells, provided a useful model for assessing the role of class I-restricted T cells in resistance to infection with virulent Mycobacterium tuberculosis. Of mutant beta 2m-/-mice infected with virulent 10(6) M. tuberculosis, 70% were dead or moribund after 6 weeks, while all control mice expressing the beta 2m gene remained alive for > 20 weeks. Granuloma formation occurred in mutant and control mice, but far greater numbers of tubercle bacilli were present in the lungs of mutant mice than in controls, and caseating necrosis was seen only in beta 2m-/-lungs. In contrast, no differences were seen in the course of infection of mutant and control mice with an avirulent vaccine strain, bacille Calmette-Guérin (BCG). Immunization with BCG vaccine prolonged survival of beta 2m-/-mice after challenge with M. tuberculosis for 4 weeks but did not protect them from death. These data indicate that functional CD8 T cells, and possibly T cells bearing gamma delta antigen receptor, are a necessary component of a protective immune response to M. tuberculosis in mice.

Primordial germ cells (PGCs) of the early chick embryo were examined using scanning electron microscopy. Temporal changes in the form and distribution of surface projections were found to be correlated with migratory phases of PGCs. Non-migrating PGCs were spherical to ovoid with relatively smooth surfaces. Their transition to the migratory phase was first evidenced by a burst of membrane activity. Migrating PGCs became somewhat flattened against the underlying hypoblast (which serves as the substratum for their migration) and exhibited blebs and lamellar processes. The lamellar processes were most prominent at the leading edges of actively migrating PGCs. Overall results of the present study indicates that PGCs found in the germinal crescent area of early chick embryos actively migrate on the dorsal surface of the hypoblast towards posterior embryonic regions.

A method is described for processing multiple cross-sections from early chick embryos for scanning electron microscopy. Embryos are cut through the desired regions. Sections are affixed to a coverslip with Duco cement and critical point dried by Freon 13 or liquid CO2. This method provides a reliable means for preparing multiple cross-sections from single embryos and eliminates the need for direct handling of brittle tissues after drying.

With the help of the radioactive blocker of M-cholinergic receptors 3H-Quinuclidinil benzylate their quantity was determined on B-lymphocytes of CBA mice spleen. On the 3rd and 4th day after immunization with ovalbumin the number of M-cholinergic receptors became somewhat higher. The specific antigen decreased the expression of M-cholinergic receptors on B-lymphocytes most of all on the 4th day after immunization, and did not have any effect on this indicator in control animals. This testifies to the possibility of steric interaction between the antigen binding immunoglobulin and M-cholinergic receptors on B-lymphocytes during the immune reaction.