Early‐pregnancy factor (EPF), first discovered in the early stages of gestation, is associated with and necessary for cell proliferation in a wide variety of biological situations. Like many other growth factors, EPF is present in platelets, and, by titration studies with a neutralising anti‐EPF monoclonal antibody, platelets were identified as an extremely rich source of this growth factor. EPF has been purified from clinically outdated human platelets by heat extraction, ion‐exchange and affinity chromatographies on SP‐Sephadex and heparin‐Sepharose respectively, high‐performance hydrophobic interaction chromatography and three reverse‐phase HPLC steps, with an average yield of 15 μg/100 platelet units (equivalent to ∼ 50 1 blood). Using SDS/PAGE, EPF migrated as a single band with approximate Mr 8500, coincident with biological activity. Mass spectrometry provided an accurate and precise determination of the molecular mass as Mr 10843.5±2, along with definitive evidence of the homogeneity of the preparation. Attempts at Edman degradation indicated that the molecule was blocked at the N‐terminus and sequencing of proteolytic fragments was undertaken. The amino acid sequence of approximately 70% of the molecule was determined which, with a single exception, is identical with rat chaperonin 10. This structural relationship was shown to extend to functional identity by studies using chaperonin 10 and its functional associate chaperonin 60. Investigations with the latter confirmed that chaperonin 10 is the moiety in pregnancy serum which initiates response in the EPF bioassay. Our studies identify EPF as a member of the highly conserved heat‐shock family of molecules and demonstrate a molecular chaperone performing an extracellular role.

Previous studies have shown that, in the mouse, a factor is produced by the fertilized ovum within 24 h of mating. It cooperates with prolactin to stimulate ovarian production of component B or early pregnancy factor (EPF). This paper presents an initial characterization of the substance, termed ovum factor (OF). An indirect assay based on the rosette inhibition test for EPF has shown that OF is first released upon penetration of the ovum by the fertilizing spermatozoon. OF continues to be produced at least until blastulation. Processes which parthenogenetically activate the ovum are also capable of stimulating OF release from unfertilized ova. Gel filtration studies reveal that OF exists in multiple MW forms of approximately 160,000; 2,800; and 1,500. A substance with these characteristics has not been described previously; it may represent the first embryonic signal to the mother.

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Hsp10 (10-kDa heat shock protein, also known as chaperonin 10 or Cpn10) is a co-chaperone for Hsp60 in the protein folding process. This protein has also been shown to be identical to the early pregnancy factor, which is an immunosuppressive growth factor found in maternal serum. In this study we have used immunogold electron microscopy to study the subcellular localization of Hsp10 in rat tissues sections embedded in LR Gold resin employing polyclonal antibodies raised against different regions of human Hsp10. In all rat tissues examined including liver, heart, pancreas, kidney, anterior pituitary, salivary gland, thyroid, and adrenal gland, antibodies to Hsp10 showed strong labeling of mitochondria. However, in a number of tissues, in addition to the mitochondrial labeling, strong and highly specific labeling with the Hsp10 antibodies was also observed in several extramitochondrial compartments. These sites included zymogen granules in pancreatic acinar cells, growth hormone granules in anterior pituitary, and secretory granules in PP pancreatic islet cells. Additionally, the mature red blood cells which lack mitochondria, also showed strong reactivity with the Hsp10 antibodies. The observed labeling with the Hsp10 antibodies, both within mitochondria as well as in other compartments/cells, was abolished upon omission of the primary antibodies or upon preadsorption of the primary antibodies with the purified recombinant human Hsp10. These results provide evidence that similar to a number of other recently described mitochondrial proteins (viz., Hsp60, tumor necrosis factor receptor-associated protein-1, P32 (gC1q-R) protein, and cytochrome c), Hsp10 is also found at a variety of specific extramitochondrial sites in normal rat tissue. These results raise important questions as to how these mitochondrial proteins are translocated to other compartments and their possible function(s) at these sites. The presence of these proteins at extramitochondrial sites in normal tissues has important implications concerning the role of mitochondria in apoptosis and genetic diseases.

Problem-based medical education is based in a biomedical worldview that works to entrench deterministic ways of thinking about socioculturally-influenced health disparities in the minds of medical trainees. This perspective paper considers the utility of Paolo Freire’s critical pedagogy as a means of redressing this issue, as it may enable medical learners to perceive and address the social sources of illness that shape their patients’ lives. With an eye to advancing health equity, and educating health professionals who are responsive to marginalized and vulnerable communities, this paper considers how a problem- posing medical education could redefine physicians’ relationships to knowledge, identity, and to their patients.

Introduction Over 50% of medical students worldwide report experiencing mistreatment and abuse during their clinical education, yet only a small proportion of students report these concerns to administration. It is unknown how medical students make sense of their experiences of mistreatment and come to decide whether to formally report these experiences. Improved understanding of this phenomenon will facilitate changes at the administrative and institutional levels to better support students. Methods Using Constructivist Grounded Theory, we interviewed 19 current and former medical students from one institution about their experiences with mistreatment and reporting. Data were analysed in an iterative fashion, using focused and theoretical forms of coding. Results The decision of whether to report mistreatment is only one phase in the process that students report experiencing when encountering mistreatment. This process can be understood as a journey consisting of five phases: Situating, Experiencing and Appraising, Reacting, Deciding and Moving Forward. Students move through these phases as they come to understand their position as medical learners and their ability to trust and be safe within this institution. Each experience of mistreatment causes students to react to what has happened to them, decide if they will share their experiences and reach out for support. They choose if they are going to report the mistreatment, at what cost and for what outcomes. Students continue through their training while incorporating their experiences into their understanding of the culture in which they are learning and continually resituating themselves within the institution. Discussion Student perceptions of trust or mistrust in their educational institution are highly influential when it comes to reporting mistreatment. Interventions designed to support students and decrease exposure to mistreatment may be best focused on increasing organisational trust between students and the medical school.

Early pregnancy factor (EPF) is a secreted substance with growth regulatory and immunomodulatory properties. It is required for successful establishment of pregnancy and for proliferation of both normal and neoplastic cells, in vivo and in vitro. The rosette inhibition test was used as a bioassay, and the appearance of EPF in serum in the very early stages of pregnancy (in mice, within 4-6 h of mating) was first described two decades ago. However, because of the difficulty of this bioassay and the paucity of EPF in biological materials, the primary structure of the molecule has been identified only recently. Seventy per cent of the amino acid sequence of EPF derived from human platelets was determined. With the exception of a single residue, this was identical to the sequence of rat mitochondrial chaperonin 10 (cpn10). Cpn10 is a heat shock protein that functions as a molecular chaperone. It binds to and stabilizes cpn60 and, in concert, these molecules mediate protein folding in mitochondria, chloroplasts and bacteria. Characterizing EPF as an extracellular form of cpn10 raises unprecedented questions about the mechanism of action. It may be that, as a molecular chaperone in the extracellular compartment, EPF can functionally modify other proteins, serving as a regulator of regulators.

Early pregnancy factor (EPF) has been produced in vitro by culture of oestrous mouse oviducts and ovaries in RPMI, with the addition of prolactin and mouse embryo culture medium. The pooled harvested medium was then subjected to immunoabsorption, electrofocusing and gel filtration. A fraction was isolated with pI 6.83 and molecular weight 21 000 which was responsible for 90% of the recovered biological activity. It appeared to be homogeneous when analysed by high-performance gel-permeation chromatography. SDS treatment showed that the molecule could be split into 3 peptides of molecular weights 10 500, 7200 and 3400, the first having activity equivalent to the EPF component EPF-A from the oviduct, while the last two combined to give activity corresponding with the ovarian component EPF-B.