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As a novel approach to studying the modulation of the polarized epithelial phenotype, we have expressed c-Fos and c-Myc estrogen receptor fusion proteins (c-FosER and c-MycER) in mammary epithelial cells. The hybrid proteins could be activated by estrogen for defined time periods and after the cells had achieved their fully polarized organization. Activation of c-MycER deregulated proliferation but did not affect epithelial polarity. Short-term activation of c-FosER induced the reversible loss of morphological and functional cell polarity. In contrast, long-term stimulation of c-FosER caused the cells to depolarize irreversibly, to invade collagen gels, and to undergo epithelial-fibroblastoid cell conversion. Our data suggest that Fos proteins are important in modulating the epithelial phenotype both in normal tissue development and in invasive processes.

The functions of Myc proteins have remained a mystery for a number of years. Recent data have now provided us with a clear working hypothesis of how myc may act. What appears to be still missing is a link between the biochemical properties of this oncoprotein and its observed biological effects. Further research will be necessary to fill this void.

This is the 16th in a series of objectives to direct resident training in Emergency Medicine. Research is recognized as an important component of physician training, yet it is often neglected in medical school and residency curricula. We offer here an objective-based program for resident physicians' exposure to research design and methodology.

Objective: There is growing concern that chronic mentally ill adults living in the community have a high risk for HIV infection. The purpose of this study was to identify risk knowledge, high-risk behaviors, and risk-related encounters of chronic psychiatric outpatients., Method: Detailed information on high-risk behaviors and risk-related situations during the past 12 months was collected from 60 outpatients appearing for regular visits at inner-city community mental health clinics., Results: Of the 60 outpatients, 37 (62%) had been sexually active during the past year, and 42% of the men and 19% of the women reported multiple sexual contacts and infrequent use of condoms during intercourse. Assessments of the patients' knowledge of AIDS risks revealed substantial deficits in their practical understanding of AIDS and risk reduction measures. Although use of intravenous drugs was uncommon in this group, many subjects reported histories of 1) trading sex for money, drugs, or a place to stay, 2) coercion to engage in unwanted sex, 3) causal sexual encounters, and 4) sexual activity after use of drugs or intoxicants. Twenty percent of the subjects had met their sexual partners on the streets, in parks, or in other public places. One-third had been treated for sexually transmitted diseases other than AIDS., Conclusions: These findings underscore the need for AIDS risk assessment, counseling, and prevention programs for the chronic mentally ill.

We report an unusual cause of unresponsiveness in a 73-year-old woman seen in the emergency department. Extensive evaluation, including an emergency EEG that demonstrated rhythmic, high-voltage spike-and-wave discharges characteristic of convulsive activity, confirmed the diagnosis of generalized tonic status epilepticus. The patient's persistent subclinical seizures terminated after the IV administration of diazepam. Varying presentations of generalized tonic status epilepticus have been described in the neurology literature, with EEG confirmation of this diagnosis. Review of the emergency medicine literature does not describe a similar presentation of altered mental status in the adult population. This case illustrates one necessary role for ED EEG in the identification of occult status epilepticus causing altered mental status.

This article outlines the objectives for a resident rotation in pulmonary diseases. It is part of a continuing series on the goals and objectives to direct Emergency Medicine resident training on off-service rotations. Pulmonary disease accounts for a high percentage of presenting complaints and potentially life-threatening disease in the emergency department. Because of the frequency of respiratory disease in Emergency Medicine, many Emergency Medicine residencies offer individual off-service rotations in Pulmonary Medicine. The objectives of this article are viewed as a one-month component of an Internal Medicine Rotation in the first year of training. These objectives are designed to help focus the resident's reading and study during a pulmonary off-service rotation.

Emergency medical services providers routinely respond to emergencies using lights and siren. This practice is not without risk of collision. Audible and visual warning devices and vehicle markings are integral to efficient negotiation of traffic and reduction of collision risk. An understanding of warning system characteristics is necessary to implement appropriate guidelines for prehospital transportation systems. The pertinent literature on emergency vehicle warning systems is reviewed, with emphasis on potential health hazards associated with these techniques. Important findings inferred from the literature are 1) red flashing lights alone may not be as effective as other color combinations, 2) there are no data to support a seizure risk with strobe lights, 3) lime-yellow is probably superior to traditional emergency vehicle colors, 4) the siren is an extremely limited warning device, and 5) exposure to siren noise can cause hearing loss. Emergency physicians must ensure that emergency medical services transportation systems consider the pertinent literature on emergency vehicle warning systems.

This is the ninth article in a continuing series for emergency medicine education. Ophthalmology is the topic. Since ophthalmologic problems are common in the emergency department and have obvious importance in clinical care, the time spent on an ophthalmology rotation can be very valuable in emergency medicine training. This experience is often limited to a 2-week rotation. Therefore, clear goals and objectives take on a greater significance for the resident-in-training.

This article is the second of two parts outlining the objectives for resident rotations in intensive care units. It is part of a larger continuing series on the goals and objectives to direct the training of emergency medicine residents on off-service rotations. The critical care unit allows the resident an opportunity to provide continuing care for critically ill patients, many of whom enter the health care system through the emergency department. Critical care medicine is a natural continuum of emergency medicine, and provides the resident with the ability to follow the natural progression of seriously ill patients, as well as build confidence and experience in caring for the critically ill and injured. These objectives are designed to help focus the resident's reading and study during the rotation.

This article is the first of two parts outlining the objectives for a resident rotating in the intensive care unit (ICU). It is part of a larger continuing series on the goals and objectives to direct the training of emergency medicine residents on off-service rotations. The critical care unit is a valuable rotation that allows the resident to see and care for critically ill patients, many of whom present initially to the emergency department. Critical care is a logical continuum for the sick and injured patient as he moves from the prehospital and emergency department (ED) settings to the ICU. These objectives are designed to focus the resident's reading and study during a critical care rotation.

Hiccups are a common, and fortunately usually transient, benign malady. Occasionally, however, hiccups fail to resolve spontaneously, resulting in patient fatigue and incapacitation and the need for the affected individual to seek medical care for resolution of the problem. The approach to the management of these patients consists of the identification and treatment of serious underlying causes of the episode as well as therapeutic interventions to achieve hiccup resolution.

This is a continuing series of objectives to direct resident training in emergency medicine. Electrocardiography may not receive individual attention in many training programs. However, the importance, omnipresence, and medicolegal potential of electrocardiography in the practice of emergency medicine suggests its individual attention. Contents and specific learning objectives are presented to provide guidelines for resident mastery, following the format presented by preceding subjects.

The proto-oncogene MYC encodes a nuclear protein whose biochemical and physiological functions remain uncertain. We used an estrogen-regulated version of the MYC protein to explore these functions. Activation of MYC in quiescent rat and mouse fibroblasts elicited re-entry into and progression through the cell cycle, bypassing early events that would follow stimulation of the cells with serum. Activation of MYC led to a rapid increase in transcription of the alpha-prothymosin gene, even in the absence of protein synthesis. We conclude that the product of MYC acts directly on transcription, in accord with inferences based on the structure of the MYC protein. The function of alpha-prothymosin is not known, but our results suggest that the protein may play a role in the proliferation of mammalian cells.

Emergency Medical Services are an area of special interest in emergency medicine. Many emergency physicians are called upon to direct, train, or manage emergency medical services. Residents training in emergency medicine have a need for a defined curriculum in emergency medical services. Residency training should provide a basic foundation in EMS including on- and off-line medical control, medicolegal aspects, communications, disaster management, and EMS history, structure, and function. The resident must gain experience through on-scene observation, EMT/Paramedic education, medical direction, and quality assurance activities. This paper is one in a continuing series of goals and objectives to direct resident training in off-service rotations. Specific resources, learning objectives, and experiences are suggested.

This is the fifth article in a continuing series on objectives to direct the training of emergency medicine residents. The emergency physician frequently must deal with hand injuries. Often these may appear innocuous; recognition of these injuries requires certain technical skills and a working knowledge of these entities. Specific objectives presented provide guidance for the didactic content as well as skill mastery for the resident experience.

This is the fifth in a continuing series of objectives to direct resident training in emergency medicine. Approximately 50% of resident experience and training in emergency medicine takes place outside of the direct control and influence of full-time emergency medicine faculty. To gain some direction and control over these off-service rotations, objectives and references are offered here. Objectives for a dermatology rotation as well as contents and references are presented.

This is the fourth article in a continuing series on objectives for emergency medicine training; plastic surgery objectives will be presented. Plastic surgery topics overlap many in emergency medicine. Specific behaviorally based objectives for mastery of skills in plastic surgery are outlined. Specific references are provided for additional information and reinforcement in skill mastery. The basic concepts of plastic surgery are probably best learned by observation and supervised performance. Specific objectives provide guidance and direction for the didactic as well as the supervised experiences in skill mastery. These objectives provide a structure for systematically learning and mastering the content presented on a plastic surgical rotation or experience in emergency medicine training.

We present the case of a 17-year-old girl who ingested 24 to 36 g fenoprofen as a suicidal gesture. She presented with coma, hypotension, metabolic acidosis, and respiratory depression within four hours of ingestion. The most common adverse effects of the nonsteroidal anti-inflammatory drugs occur in both therapeutic and toxic doses and include gastrointestinal upset, blood dyscrasias, and analgesic nephropathy. The propionic acid derivatives of nonsteroidal anti-inflammatory drugs, including fenoprofen and ibuprofen, are rarely associated with severe toxic effects. This is the first report of pure fenoprofen overdose presenting as coma and metabolic acidosis.

In this third article in a continuing series on objectives for emergency medicine training, orthopedic objectives are presented. Orthopedic complaints are common in emergency medicine. Direction in mastering evaluative, cognitive, and procedural skills are provided utilizing behaviorally based objectives and references. These objectives provide a structure for systematically learning the content of orthopedics through enlightened patient care, questioning of attending physicians and supervisors, and directed reading.

Patients presenting for emergency care with complaints of dental origin are common. Rarely are dental topics systematically addressed during training rotations. In this second article in a continuing series on objectives for emergency medicine resident training, dental emergency objectives will be presented. Instructions for use of the references and objectives are provided. Cognitive and evaluative objectives are organized for mastery. A list of resources including references and audio visual materials are outlined. The objectives and reference materials presented provide a structure for the systematic study of dental emergencies in emergency medicine resident training.

A mounting body of evidence suggests that cytoplasmically synthesized proteins destined to be imported into the mitochondrial interior must at least partly unfold to penetrate across the mitochondrial membranes. During post-translational import, this unfolding process appears to be a major rate-limiting step. It can be blocked by ligands that stabilize the protein's native conformation and appears to be accompanied by the cleavage of ATP outside the mitochondrial inner membrane.

The human proto-oncogene myc encodes a nuclear phosphoprotein whose primary biochemical function is still unknown. To facilitate further study of that function, we have created conditional alleles of myc by fusing the hormone-binding domain of the human oestrogen receptor gene to the 5' or the 3' end of human myc. The two chimaeric genes, designated mycer and ermyc, encode proteins that bind oestrogen with high affinity. Expression of one of the genes, mycer, transforms a rat fibroblast cell line in a tightly oestrogen-dependent manner. Transformation is dependent on the presence of a functional myc gene in the chimaera and is reversible upon removal of the hormone. The chimaeric genes will be useful tools to study the mechanisms by which Myc affects cellular phenotype. Recently, chimaeras between the adenovirus E1A protein and the hormone binding domain of the rat glucocorticoid receptor were shown to activate transcription in a manner characteristic for E1A, but in a hormone regulated manner. We therefore asked whether the same strategy could be applied to the product of myc.

An artificial mitochondrial precursor protein (the presequence of cytochrome oxidase subunit IV fused to mouse dihydrofolate reductase) binds to isolated yeast mitochondrial outer membranes and to liposomes whose phospholipid composition resembles that of outer membranes. In both cases, binding is strongly inhibited by low temperature or methotrexate (which stabilizes the dihydrofolate reductase moiety) and partly inhibited by adriamycin (which binds to acidic phospholipids). Binding is accompanied by partial unfolding of the protein. Binding of the urea-denatured fusion protein to outer membranes or liposomes is insensitive to low temperature, methotrexate, or adriamycin. These results, and those reported in the accompanying paper (Eilers, M., Endo, T., and Schatz, G. (1989) J. Biol. Chem. 264, 2945-2950) suggest that import of this fusion protein into isolated mitochondria involves at least partial unfolding by acidic phospholipids on the mitochondrial surface.

Methotrexate, a folate antagonist, blocks import into mitochondria of mouse dihydrofolate reductase fused to a mitochondrial presequence. Methotrexate does not mask the presequence, but stabilizes the dihydrofolate reductase moiety. It does not inhibit import of the authentic precursor from which the presequence is derived. This suggests that dihydrofolate reductase must at least partly unfold in order to be transported across mitochondrial membranes.

We have investigated the energy requirement of mitochondrial protein import with a simplified system containing only isolated yeast mitochondria, energy sources and a purified precursor protein. This precursor was a fusion protein composed of 22 residues of the cytochrome oxidase subunit IV pre-sequence fused to mouse dihydrofolate reductase. Import of this protein required not only an energized inner membrane, but also ATP. ATP could be replaced by GTP, but not by CTP, TTP or non-hydrolyzable ATP analogs. Added ATP did not increase the membrane potential of respiring mitochondria; it supported import even if the proton-translocating mitochondrial ATPase and the entry of ATP into the matrix were blocked. We conclude that ATP exerts its effect on mitochondrial protein import outside the inner membrane.

Acidic phospholipids such as cardiolipin partially unfold an artificial precursor protein which consists of a mitochondrial presequence fused to mouse dihydrofolate reductase (Endo, T., and Schatz, G. (1988) EMBO J. 7, 1153-1158). We now show that import of this precursor protein into isolated yeast mitochondria is blocked by adriamycin, a drug binding to cardiolipin and other acidic phospholipids. This inhibition is lessened if the precursor's dihydrofolate reductase moiety is labilized by point mutations; inhibition is abolished altogether if the "wild-type" precursor is presented to mitochondria in a urea-denatured state. These and other observations suggest that adriamycin interferes with the generation of a translocation-competent, loose structure of the precursor protein. They imply that acidic phospholipids such as cardiolipin participate, directly or indirectly, in the translocation of this fusion protein into isolated mitochondria.

A purified mitochondrial precursor protein unfolds to a protease-sensitive conformation at the surface of isolated mitochondria before being imported into the organelles. This unfolding is stimulated by a potential across the mitochondrial inner membrane, but does not require ATP. In contrast, import of the surface-bound unfolded precursor requires ATP, but no potential; it is accompanied by a refolding inside the mitochondria.

Up to 50% of the 36 months of resident training in emergency medicine may be on off-service rotations. The experience on these rotations can lack educational content and opportunity pertinent to emergency medicine. The resident rarely has readily available and structured guidance to optimize training in terms of the anticipated needs of the specialty. In response to this problem, the authors have written curricula containing subject content listings, objectives, and supplied references for 16 off-service rotations. A plan for implementing the materials and an example from the obstetrics-gynecology rotation is given. After 12 months' experience, the authors have subjective responses from residents and off-service program directors that support the value of this information. Positive reports include: Residents having a better understanding of faculty expectations, improved "consistency of experience," residents appreciating the added attention, improved performance, and expanded reading efforts. One expressed concern is "too much to read." The project continues to evolve.

The amino-terminal sequences of several imported mitochondrial precursor proteins have been shown to contain all the information required for transport to and sorting within mitochondria. Proteins transported into the matrix contain a matrix-targeting sequence. Proteins destined for other submitochondrial compartments contain, in addition, an intramitochondrial sorting sequence. The sorting sequence in the cytochrome c1 presequence is a stop-transport sequence for the inner mitochondrial membrane. Proteins containing cleavable presequences can reach the intermembrane space by either of two pathways: (1) Part of the presequence is transported into the matrix; the attached protein, however, is transported across the outer but not the inner membrane (eg, the cytochrome c1 presequence). (2) The precursor is first transported into the matrix; part of the presequence is then removed, and the protein is reexported across the inner membrane (eg, the precursor of the iron-sulphur protein of the cytochrome bc1 complex). Matrix-targeting sequences lack primary amino acid sequence homology, but they share structural characteristics. Many DNA sequences in a genome can potentially encode a matrix-targeting sequence. These sequences become active if positioned upstream of a protein coding sequence. Artificial matrix-targeting sequences include synthetic presequences consisting of only a few different amino acids, a known amphiphilic helix found inside a cytosolic protein, and the presequence of an imported chloroplast protein. Transport of proteins across mitochrondrial membranes requires a membrane potential, ATP, and a 45-kd protein of the mitochondrial outer membrane. The ATP requirement for import is correlated with a stable structure in the imported precursor molecule. We suggest that transmembrane transport of a stably folded precursor requires an ATP-dependent unfolding of the precursor protein.