bluuebunny/crossref_metadata_2025 huggingface dataset:
Calcineurin/NFAT Coupling Participates in Pathological, but not Physiological, Cardiac Hypertrophy
Authors: Wilkins Benjamin J. , Dai Yan-Shan , Bueno Orlando F. , Parsons Stephanie A. , Xu Jian , Plank David M. , Jones Fred , Kimball Thomas R. , Molkentin Jeffery D.
Published: December 2003

Calcineurin (PP2B) is a calcium/calmodulin-activated, serine-threonine phosphatase that transmits signals to the nucleus through the dephosphorylation and translocation of nuclear factor of activated T cell (NFAT) transcription factors. Whereas calcineurin-NFAT signaling has been implicated in regulating the hypertrophic growth of the myocardium, considerable controversy persists as to its role in maintaining versus initiating hypertrophy, its role in pathological versus physiological hypertrophy, and its role in heart failure. To address these issues, NFAT-luciferase reporter transgenic mice were generated and characterized. These mice showed robust and calcineurin-specific activation in the heart that was inhibited with cyclosporin A. In the adult heart, NFAT-luciferase activity was upregulated in a delayed, but sustained manner throughout eight weeks of pathological cardiac hypertrophy induced by pressure-overload, or more dramatically following myocardial infarction-induced heart failure. In contrast, physiological hypertrophy as produced in two separate models of exercise training failed to show significant calcineurin-NFAT coupling in the heart at multiple time points, despite measurable increases in heart to body weight ratios. Moreover, stimulation of hypertrophy with growth hormone–insulin-like growth factor-1 (GH-IGF-1) failed to activate calcineurin-NFAT signaling in the heart or in culture, despite hypertrophy, activation of Akt, and activation of p70 S6K.
Calcineurin Aβ
gene–targeted mice also showed a normal hypertrophic response after GH-IGF-1 infusion. Lastly, exercise- or GH-IGF-1–induced cardiac growth failed to show induction of hypertrophic marker gene expression compared with pressure-overloaded animals. Although a direct cause-and-effect relationship between NFAT-luciferase activity and pathological hypertrophy was not proven here, our results support the hypothesis that separable signaling pathways regulate pathological versus physiological hypertrophic growth of the myocardium, with calcineurin-NFAT potentially serving a regulatory role that is more specialized for maladaptive hypertrophy and heart failure.
Perlecan-Induced Suppression of Smooth Muscle Cell Proliferation Is Mediated Through Increased Activity of the Tumor Suppressor PTEN
Authors: Garl Pamela J. , Wenzlau Janet M. , Walker Heather A. , Whitelock John M. , Costell Mercedes , Weiser-Evans Mary C.M.
Published: December 2003

We were interested in the elucidation of the interaction between the heparan sulfate proteoglycan, perlecan, and PTEN in the regulation of vascular smooth muscle cell (SMC) growth. We verified serum-stimulated DNA synthesis, and Akt and FAK phosphorylation were significantly reduced in SMCs overexpressing wild-type PTEN. Our previous studies showed perlecan is a potent inhibitor of serum-stimulated SMC growth. We report in the present study, compared with SMCs plated on fibronectin, serum-stimulated SMCs plated on perlecan exhibited increased PTEN activity, decreased FAK and Akt activities, and high levels of p27, consistent with SMC growth arrest. Adenoviral-mediated overexpression of constitutively active Akt reversed perlecan-induced SMC growth arrest while morpholino antisense-mediated loss of endogenous PTEN resulted in increased growth and phosphorylation of FAK and Akt of SMCs on perlecan. Immunohistochemical and Western analyses of balloon-injured rat carotid artery tissues showed a transient increase in phosphoPTEN (inactive) after injury, correlating to high rates of neointimal cell replication; phosphoPTEN was largely limited to actively replicating SMCs. Similarly, in the developing rat aorta, we found increased PTEN activity associated with increased perlecan deposition and decreased SMC replication rates. However, significantly decreased PTEN activity was detected in aortas of perlecan-deficient mouse embryos, consistent with SMC hyperplasia observed in these animals, compared with E17.5 heterozygous controls that produce abundant amounts of perlecan at this developmental time point. Our data show PTEN is a potent endogenously produced inhibitor of SMC growth and increased PTEN activity mediates perlecan-induced suppression of SMC proliferation.
Antagonism of RANTES Receptors Reduces Atherosclerotic Plaque Formation in Mice
Authors: Veillard Niels R. , Kwak Brenda , Pelli Graziano , Mulhaupt Flore , James Richard W. , Proudfoot Amanda E.I. , Mach François
Published: December 2003

Increasing evidence supports the involvement of inflammation in the early phases of atherogenesis. Recruitment of leukocytes within the vascular wall, controlled by chemokines, is an essential process in the development of this common disease. In this study, we report that blocking a chemokine pathway in vivo with the CC chemokine antagonist Met-RANTES reduces the progression of atherosclerosis in a hypercholesterolemic mouse model. The reduction of lesions was correlated with a diminution of expression of several major chemokines and chemokine receptors, a decrease in leukocyte infiltration, and an increase of collagen-rich atheroma, features associated with stable atheroma. Treatment was well tolerated and serum lipid profiles were not affected. Whereas genetically engineered mice with deletion of either a CC chemokine or its receptor have demonstrated resistance to disease, to our knowledge, this is the first demonstration that treatment with a chemokine receptor antagonist limits the progression of atherosclerosis in vivo. Thus, our findings indicate that blockade of chemokine receptor/ligand interactions might become a novel therapeutic strategy to reduce the evolution of this common disease.
Anti–α-Fodrin Autoantibodies in Moyamoya Disease
Authors: Ogawa Kouichi , Nagahiro Shinji , Arakaki Rieko , Ishimaru Naozumi , Kobayashi Masaru , Hayashi Yoshio
Published: December 2003

Background and Purpose—

Moyamoya disease (MMD) is a rare entity that results in progressive occlusion of the arteries of the circle of Willis, but the pathogenesis of MMD is unknown.

Methods—

MMD sera (n=32) were tested for anti-endothelial cell antibodies by enzyme-linked immunoassays and flow cytometric analysis. Apoptosis was induced in human umbilical vein endothelial cells by tumor necrosis factor-α.

Results—

We found that a high proportion of MMD sera had anti-endothelial cell antibodies with apoptotic stimuli. Prominent reactivities of MMD sera (72%) with recombinant human α-fodrin were observed.

Conclusions—

Our study demonstrates that MMD sera contain a high incidence of anti–α-fodrin autoantibodies, providing new insight into the mechanisms of occlusion of MMD arteries.
Intracranial Heme Metabolism and Cerebral Vasospasm After Aneurysmal Subarachnoid Hemorrhage
Authors: Suzuki Hidenori , Muramatsu Masatoshi , Kojima Tadashi , Taki Waro
Published: December 2003

Background and Purpose—

The goal of this prospective study was to clarify the potential role of an inducible heme-metabolizing enzyme, heme oxygenase (HO)-1, and an inducible iron-detoxifying protein, ferritin, in cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH).

Methods—

The authors measured the levels of bilirubin and iron, which are by-products of HO-1, and the ferritin levels in the cerebrospinal fluid in 39 consecutive patients with aneurysmal SAH of Fisher computed tomography group III, and determined the relationship between these by-products of HO-1 or ferritin and vasospasm.

Results—

Fourteen of 39 patients (35.9%) developed asymptomatic vasospasm, while 6 patients (15.4%) developed symptomatic vasospasm. The levels of ferritin, bilirubin, and iron were all significantly elevated after SAH. The levels of ferritin and bilirubin were significantly higher in patients with no vasospasm than in patients with asymptomatic and symptomatic vasospasm on days 5 through 7 (
P
<0.05, respectively) and on days 11 through 14 (
P
<0.025 in bilirubin) after SAH. However, no significant difference was observed in the iron levels between these patient groups.

Conclusions—

This is the first study to show that higher levels of bilirubin and ferritin in the cerebrospinal fluid after SAH were associated with no vasospasm in clinical settings. These findings support the concept that the induction of HO-1 and ferritin may be an intrinsic regulatory mechanism that acts against cerebral vasospasm.
Prophylactic Management of Excessive Natriuresis With Hydrocortisone for Efficient Hypervolemic Therapy After Subarachnoid Hemorrhage
Authors: Moro Nobuhiro , Katayama Yoichi , Kojima Jun , Mori Tatsuro , Kawamata Tatsuro
Published: December 2003

Background and Purpose—

Hyponatremia caused by excessive natriuresis is common in patients with aneurysmal subarachnoid hemorrhage (SAH). Natriuresis decreases the total blood volume through osmotic diuresis and increases the risk of symptomatic cerebral vasospasm. In such patients, hypervolemic therapy is difficult to achieve without causing hyponatremia because sodium replacement provokes further natriuresis and osmotic diuresis. We examined the effects of hydrocortisone, which promotes sodium retention, in patients with SAH.

Methods—

Twenty-eight SAH patients were randomized into 2 groups after direct surgery: group 1 patients without hydrocortisone treatment (n=14) and group 2 patients with hydrocortisone treatment (1200 mg/d for 10 days; n=14). Both groups underwent hypervolemic therapy by aggressive sodium and water replacement. The goal of the hypervolemic therapy was to maintain the serum sodium level >140 mEq/L and the central venous pressure (CVP) within 8 to 12 cm H
2
O.

Results—

Group 2 demonstrated a lower sodium excretion (
P
<0.05) and higher serum sodium level (
P
<0.05) compared with group 1. Hyponatremia developed in 6 patients (43%) in group 1 and 0 patients in group 2 (
P
<0.05). Group 2 also demonstrated a lower urine volume, lower infusion volume (
P
<0.05) required for hypervolemic therapy, and higher CVP (
P
<0.05). Failure to maintain CVP was observed in 12 patients (86%) in group 1 and 3 patients (21%) in group 2 (
P
<0.05). Hydrocortisone caused no serious side effects.

Conclusions—

Hydrocortisone clearly attenuates excessive natriuresis. Prophylactic hydrocortisone administration appears to have a therapeutic value in inducing hypervolemia efficiently after SAH.
Breaking the Cloud Parameterization Deadlock
Authors: Randall David , Khairoutdinov Marat , Arakawa Akio , Grabowski Wojciech
Published: December 2003

A key factor limiting the reliability of simulations of anthropogenic climate change is the inability to accurately represent the various effects of clouds on climate. Despite the best efforts of the community, the problem has resisted solution for several decades. The reasons for this are briefly reviewed and it is argued that it will be many more decades before the problem can be solved through the approaches to cloud parameterization that have been used up to now. An alternative approach, called superparameterization, is then outlined, in which high-resolution cloud system-resolving models (CSRMs) are used in place of the conventional cloud parameterizations. Tests performed with the Community Atmosphere Model show that superparameterizations can give more realistic simulations of the current climate, including greatly improved simulations of the Madden–Julian oscillation and other tropical wave disturbances. Superparameterizations increase the cost of climate simulation by a factor of several hundred dollars, but can make efficient use of massively parallel computers. In addition, superparameterizations make it possible for a climate model to converge to a global CSRM as the horizontal grid spacing of the climate model decreases to a few kilometers. No existing global atmospheric model has this convergence property. Superparameterizations have the potential to greatly increase the reliability of climate change simulations.
Assimilation of Satellite Sea Surface Temperature Retrievals
Authors: Harris Andrew , Maturi Eileen
Published: December 2003

The Workshop on Assimilation of Satellite Sea Surface Temperatures (SST) Retrievals was held on 24–26 April 2001 in Camp Springs, Maryland, at the National Oceanic and Atmospheric Administration (NOAA) Science Center. The purpose of the workshop was for NOAA's National Environmental Satellite Data and Information Service Office of Research and Applications to initiate a collaborative project with the U.S. Navy, National Centers for Environmental Prediction, the industry, and academia. The concept of the project was to develop an optimal method for assimilating satellite data into operational analyses of sea surface temperature. The aim of the workshop was to develop a demonstration system with the following results. First, ensure that the advantages of each data type (polar orbiting and geostationary) are fully exploited, while minimizing the impact of potential errors. Second, employ state-of-the-art radiative transfer modeling, variational assimilation techniques, intersensor calibration, and use of external data such as upper-air temperatures and humidities. The resulting product will represent the next big step in use of satellite data for sea surface temperature and should be the product of choice for numerical weather prediction, operational oceanography, and fisheries and climate research.
The plaque lipid lysophosphatidic acid stimulates platelet activation and platelet-monocyte aggregate formation in whole blood: involvement of P2Y1 and P2Y12 receptors
Authors: Haserück Nadine , Erl Wolfgang , Pandey Dharmendra , Tigyi Gabor , Ohlmann Philippe , Ravanat Catherine , Gachet Christian , Siess Wolfgang
Published: December 2003

Despite the fact that lysophosphatidic acid (LPA) has been identified as a main platelet-activating lipid of mildly oxidized low-density lipoprotein (LDL) and human atherosclerotic lesions, it remains unknown whether it is capable of activating platelets in blood. We found that LPA at concentrations slightly above plasma levels induces platelet shape change, aggregation, and platelet-monocyte aggregate formation in blood. 1-alkyl-LPA (16:0 fatty acid) was almost 20-fold more potent than 1-acyl-LPA (16:0). LPA directly induced platelet shape change in blood and platelet-rich plasma obtained from all blood donors. However, LPA-stimulated platelet aggregation in blood was donor dependent. It could be completely blocked by apyrase and antagonists of the platelet adenosine diphosphate (ADP) receptors P2Y1 and P2Y12. These substances also inhibited LPA-induced aggregation of platelet-rich plasma and aggregation and serotonin secretion of washed platelets. These results indicate a central role for ADP-mediated P2Y1 and P2Y12 receptor activation in supporting LPA-induced platelet aggregation. Platelet aggregation and platelet-monocyte aggregate formation stimulated by LPA was insensitive to inhibition by aspirin. We conclude that LPA at concentrations approaching those found in vivo can induce platelet shape change, aggregation, and platelet-monocyte aggregate formation in whole blood and suggest that antagonists of platelet P2Y1 and P2Y12 receptors might be useful preventing LPA-elicited thrombus formation in patients with cardiovascular diseases.
Angiogenic switch during 5T2MM murine myeloma tumorigenesis: role of CD45 heterogeneity
Authors: Asosingh Kewal , De Raeve Hendrik , Menu Eline , Van Riet Ivan , Van Marck Eric , Van Camp Benjamin , Vanderkerken Karin
Published: December 2003

The active role of angiogenesis during disease progression is well recognized in solid tumors. In hematologic malignancies such as multiple myeloma (MM), it is not known whether tumor neovascularization is an epiphenomenon or whether it is actively involved in disease progression. At clinical presentation, myeloma disease and the associated angiogenesis are both well established. Here the 5T2MM murine model was used to analyze angiogenesis during preclinical myeloma stages. Bone marrow (BM) of 5T2MM-inoculated mice was analyzed at weekly intervals until the end stage of the disease. Histologic analysis and assessment of microvessel density (MVD) by CD31 staining demonstrated a preangiogenic stage of small tumor aggregates followed by an angiogenic switch and subsequently an angiogenic stage of progressive tumor growth and large, confluent tumor nodules. Flow cytometric analysis that indicated an increase in percentage CD45- MM cells preceded the angiogenic switch. Real-time polymerase chain reaction (RT-PCR) of sorted CD45+ and CD45- MM cells indicated higher vascular endothelial growth factor 120 (VEGF120) and VEGF164 transcripts in CD45- MM cells. VEGF enzyme-linked immunosorbent assay (ELISA) revealed high secretion by CD45- MM cells but no protein secretion by CD45+ MM cells, indicating angiogenic heterogeneity among the MM cells. These data suggest that, like in solid tumors, angiogenic switch and angiogenic heterogeneity exist in MM. (Blood. 2004;103:3131-3137)
Multiparameter analysis of murine bone marrow side population cells
Authors: Pearce Daniel J. , Ridler Christopher M. , Simpson Catherine , Bonnet Dominique
Published: December 2003

We describe the multiparameter flow cytometric analysis of the relationship between side population (SP) formation and well-characterized, antigen-defined stem cell subsets. We also compared the competitive repopulation ability of subsets defined by the SP profile to those identified by antigenic markers. The vast majority of SP cells possessed a primitive cell phenotype (c-kit+, SCA-1+, Thy-1+, CD31+, CD135neg, lineageneg), but only a minority of antigen-defined subsets were SP cells. Hence, although SP cells are identified independently of antigenic markers, they are not distinct from established stem cell phenotypes, but are a small subset of them. Approximately half of SP cells expressed CD34 at readily detectable levels, and one-third of SP cells possessed the primitive c-kit+, SCA-1+, lineageneg, CD34neg cell phenotype. Since most SP cells are a subset of c-kit+, Thy-1+, lineageneg, SCA-1+ cells (KTLS), we determined whether the SP cell subset represents a further enrichment in long-term repopulating cell content. The SP+ subset of KTLS+ cells was more enriched for competitive repopulation units than the SP- fraction of KTLS+ cells. Hence, the SP cell fraction highlights a subset of the long-term repopulating cells found within the already highly purified KTLS fraction.
Potent inhibition of human platelets by cGMP analogs independent of cGMP-dependent protein kinase
Authors: Gambaryan Stepan , Geiger Jörg , Schwarz Ulrike R. , Butt Elke , Begonja Antonija , Obergfell Achim , Walter Ulrich
Published: December 2003

Platelets play a key role in hemostasis through their ability to rapidly adhere to activated or injured endothelium, subendothelial matrix proteins, and other activated platelets. A strong equilibrium between activating and inhibiting processes is essential for normal platelet and vascular function, impairment of this equilibrium being associated with either thrombophilic or bleeding disorders. Both cyclic guanosine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP) have been established as crucial and synergistic intracellular messengers that mediate the effects of platelet inhibitors such as nitric oxide (NO) and prostacyclin (PG-I2). However, it was recently suggested that a rapid cGMP/cGMP-dependent protein kinase (cGK)–mediated extracellular signal-related kinase (ERK) phosphorylation promotes platelet activation. This hypothesis was examined here by evaluating established and proposed cGK activators/inhibitors with respect to their capacity to promote either platelet activation or inhibition. In particular, the regulatory role of cGK for ERK phosphorylation and thrombin-, thromboxane-, and VWF-induced platelet activation was investigated. The data obtained do not support the concept that cGK-mediated ERK phosphorylation promotes platelet activation but confirm the inhibitory role of cGK in platelet function. One explanation for these discrepancies is the novel finding that extracellular cGMP analogs potently and rapidly inhibit thrombin-, thromboxane-, and VWF-induced human platelet signaling and activation by a cGK-independent mechanism.
The impact of cytomegalovirus serostatus of donor and recipient before hematopoietic stem cell transplantation in the era of antiviral prophylaxis and preemptive therapy
Authors: Boeckh Michael , Nichols W. Garrett
Published: December 2003

In the current era of effective prophylactic and preemptive therapy, cytomegalovirus (CMV) is now a rare cause of early mortality after hematopoietic stem cell transplantation (HSCT). However, the ultimate goal of completely eliminating the impact of CMV on survival remains elusive. Although the direct effects of CMV (ie, CMV pneumonia) have been largely eliminated, several recent cohort studies show that CMV-seropositive transplant recipients and seronegative recipients of a positive graft appear to have a persistent mortality disadvantage when compared with seronegative recipients with a seronegative donor. Recipients of T-cell–depleted allografts and/or transplants from unrelated or HLA-mismatched donors seem to be predominantly affected. Reasons likely include both incomplete prevention of direct and indirect or immunomodulatory effects of CMV as well as consequences of drug toxicities. The effect of donor CMV serostatus on outcome remains controversial. Large multicenter cohort studies are needed to better define the subgroups of seropositive patients that may benefit from intensified prevention strategies and to define the impact of CMV donor serostatus in the era of high-resolution HLA matching. Prevention strategies may require targeting both the direct and indirect effects of CMV infection by immunologic or antiviral drug strategies.
Bedside Diagnosis of Vertigo: Value of the History and Neurological Examination
Authors: Delaney Kathleen A.
Published: December 2003

Vertigo is caused by disturbance of the input or central processing of sensory signals from the vestibular apparatus that provide information regarding the position of the body in space. It is caused either by asymmetric disruption of sensory input from the vestibular organs or asymmetric integration of vestibular input into the central nervous system. Vertigo is readily differentiated from other causes of dizziness by a sensation of motion. A crucial aspect of the management of the emergency department patient with vertigo is the differentiation of vertigo associated with acute stroke syndromes from vertigo due to peripheral causes. Routine computerized axial tomography imaging is insensitive for posterior circulation strokes, so for emergency physicians, the history and neurological examination remain the most useful diagnostic tools. This article emphasizes the history and physical examination in the localization of the lesion in patients with vertigo and offers a rational basis for decisions regarding the need for special neurological imaging and consultation. It also emphasizes subtle findings that may prevent the erroneous diagnosis of peripheral vertigo in the presence of an acute stroke syndrome.
Influenza A in Young Children with Suspected Respiratory Syncytial Virus Infection
Authors: Friedman Marla J. , Attia Magdy W.
Published: December 2003

Objectives: To determine the prevalence of influenza A in young children suspected of having respiratory syncytial virus (RSV) infection and to compare the clinical presentation of these patients with those who have proven RSV infection. Methods: Children younger than or at 36 months of age who presented to a pediatric emergency department (ED) with suspected RSV infection during the influenza A season of 2001–2002 were eligible. Eligible children had an RSV antigen test ordered as part of their initial clinical management. A consecutive sample of children was enrolled for prospective observational analysis. The main outcome measure was the prevalence of influenza A in young children with suspected RSV infection. The secondary outcome measure was a comparison of the clinical presentations, of the two groups. Results: During the study period, 420 patients presented for evaluation of respiratory illness. RSV tests were ordered on 251 patients. Of 197 eligible patients, 124 (63%) tested positive for RSV and 33 (17%) for influenza A. Influenza A patients were more likely to have temperatures at or above 39°C than RSV patients (36% vs. 15%; p = 0.01). RSV patients were more tachypneic (54 vs. 43 breaths/minute; p < 0.0001) and more often had wheezing (90% vs. 8%; p < 0.0001). Twenty influenza patients (61%) were hospitalized. Conclusions: This study found a high prevalence of influenza A in young children suspected of having RSV infection. Clinicians should consider influenza A in young febrile children presenting with respiratory illnesses.
Intraosseous Emergency Access by Physicians Wearing Full Protective Gear
Authors: Ben‐Abraham Ron , Gur Ilan , Vater Youri , Weinbroum Avi A.
Published: December 2003

Objectives: To assess prospectively and randomly the feasibility, speed, and success rate of establishing an intraosseous access using the Bone Injection Gun (BIG) while wearing antichemical outfits. Methods: Attempts to introduce intraosseous injection with or without a full protective gear (antichemical body suit, face mask, and butyl gloves) were performed using a turkey bone model. Time to proper placement was measured. Results: The average time to successfully insert the BIG's needle while wearing a protective gear was 32 ± 3 seconds compared with 22 ± 2 seconds (p < 0.05) without the outfit. Success rate was greater than or equal to 80%. When failure occurred, a second attempt always proved successful. Conclusions: The intraosseous insertion of the BIG's needle is rapid and easy but requires 50% more time when wearing protective gear than without it. Its use during emergent treatment of toxic mass casualty is of potential benefit and needs further investigation.
Patient Opinions and Attitudes toward Medical Student Procedures in the Emergency Department
Authors: Graber Mark A. , Pierre Jessica , Charlton Mary
Published: December 2003

Objectives: To determine emergency department (ED) patients' preferences about having medical students perform procedures as part of medical student clinical training. Methods: A questionnaire was administered to a sequential sample of 150 patients of 196 approached (76.5% participation rate) in a teaching hospital ED. Patients were asked how many procedures a medical student should have performed on other patients before the participant would allow the student to perform the procedure on them. The procedures included venipuncture, starting an IV, suturing the face, suturing the arm, performing a lumbar puncture, starting a central line, inserting a nasogastric tube, intubation, and cardioversion. Results: If they had their preference, only a minority of patients would allow medical students to perform their first procedure on them for any of the procedures (a high of 42% for venipuncture, with a low of 7% for a lumbar puncture). Many patients prefer that medical students never perform a procedure on them (a high of 56% for a central line and a low of 21% for venipuncture). Patient beliefs were independent of age, gender, or insurance status. Conclusions: Patients are reluctant to be a medical student's first patient when it comes to procedures in the ED. This has implications for medical training and informed consent.
Resident Perceptions of Medical Errors in the Emergency Department
Authors: Schenkel Stephen M. , Khare Rahul K. , Rosenthal Marilynn M. , Sutcliffe Kathleen M. , Lewton Elizabeth L.
Published: December 2003

Objectives: To evaluate resident experience and perceptions of medical error associated with emergency department (ED) care. Methods: Using a semistructured interview protocol, three researchers interviewed 26 randomly selected medical, surgical, and obstetrics residents regarding medical error. The authors chose a 16‐case subset of incidents involving ED care for initial review. Interview transcripts were reviewed iteratively to draw out recurrent categories and themes. Two investigators separately analyzed all cases to ensure common understanding and agreement. Results: Most cases involved misdiagnosis, misread radiographs, or inappropriate disposition. Two thirds of the case patients died or experienced delays in care. Residents felt that the complexity of the patients, as well as the complexity of their own jobs, contributed to error. Attending supervision, nurse evaluation, and additional physician involvement all were noted to be important checks within the hospital system. Residents most often held the ED responsible for error. In addition, they deemed themselves, their teams, and their lack of training responsible. Though residents often discussed events with their admitting teams, follow‐up with the ED or other associated individuals was uncommon. The findings revealed seven common themes that include factors contributing to errors, checks and adaptations, and follow‐up of the event. Conclusions: Residents are aware of medical error and able to recall events in detail. Whereas events are discussed among inpatient teams, little information finds its way back to the ED, potentially resulting in misunderstandings between departments and hindering learning from events. In‐depth interviewing allows a nuanced and detailed approach to error analysis.
Calcium-Sensing Receptor Induces Proliferation through p38 Mitogen-Activated Protein Kinase and Phosphatidylinositol 3-Kinase But Not Extracellularly Regulated Kinase in a Model of Humoral Hypercalcemia of Malignancy
Authors: Tfelt-Hansen J. , Chattopadhyay N. , Yano S. , Kanuparthi D. , Rooney P. , Schwarz P. , Brown E. M.
Published: December 2003

Using H-500 rat Leydig cancer cells as a model of humoral hypercalcemia of malignancy (HHM), we previously showed that high Ca2+ induces PTH-related peptide (PTHrP) secretion via the calcium-sensing receptor (CaR) and mitogen- and stress-activated kinases, e.g. MAPK kinase 1 (MEK1), p38 MAPK, and stress-activated protein kinase 1/c-Jun N-terminal kinase. Because cellular proliferation is a hallmark of malignancy, we studied the role of the CaR in regulating the proliferation of H-500 cells. Elevated Ca2+ has a mitogenic effect on these cells that is mediated by the CaR, because the calcimimetic NPS R-467 also induced proliferation. Inhibition of phosphatidylinositol 3-kinase (PI3K) and p38 MAPK but not MEK1 abolished the mitogenic effect. Activation of PI3K by elevated Ca2+ was documented by phosphorylation of its downstream kinase, protein kinase B. Because protein kinase B activation promotes cell survival, we speculated that elevated Ca2+ might protect H-500 cells against apoptosis. Using terminal uridine deoxynucleotidyl nick end labeling staining, we demonstrated that high Ca2+ (7.5 mm) and NPS R-467 indeed protect cells against apoptosis induced by serum withdrawal compared with low Ca2+ (0.5 mm). Because the CaR induces PTHrP secretion, it is possible that the mitogenic and antiapoptotic effects of elevated Ca2+ could be indirect and mediated via PTHrP. However, blocking the type 1 PTH receptor with PTH (7–34) peptide did not alter either high Ca2+-induced proliferation or protection against apoptosis. Taken together, our data show that activation of PI3K and p38 MAPK but not of MEK1/ERK by the CaR promotes proliferation of H-500 cells as well as affords protection against apoptosis. These effects are likely direct without the involvement of PTHrP in an autocrine mode.
The Orphan Nuclear Receptors NURR1 and NGFIB Regulate Adrenal Aldosterone Production
Authors: Bassett Mary H. , Suzuki Takashi , Sasano Hironobu , White Perrin C. , Rainey William E.
Published: December 2003

Aldosterone biosynthesis in the zona glomerulosa of the adrenal cortex is regulated by transcription of CYP11B2 (encoding aldosterone synthase). The effects of nerve growth factor-induced clone B (NGFIB) (NR4A1), Nur-related factor 1 (NURR1) (NR4A2), and steroidogenic factor-1 (SF-1) (NR5A1) on transcription of human CYP11B2 (hCYP11B2) and hCYP11B1 (11β-hydroxylase) were compared in human H295R adrenocortical cells. hCYP11B2 expression was increased by NGFIB and NURR1. Although hCYP11B1 was activated by SF-1, cotransfection with SF-1 inhibited activation of hCYP11B2 by NGFIB and NURR1. NGFIB and NURR1 transcript and protein levels were strongly induced by angiotensin (Ang) II, the major regulator of hCYP11B2 expression in vivo. Sequential deletion and mutagenesis of the hCYP11B2 promoter identified two functional NGFIB response elements (NBREs), one located at −766/−759 (NBRE-1) and the previously studied Ad5 element at −129/−114. EMSAs suggested that both elements bound NGFIB and NURR1. In human adrenals, NURR1 immunoreactivity was preferentially localized in the zona glomerulosa and to a lesser degree in the zona fasciculata, whereas NGFIB was detected in both zones. The calmodulin kinase inhibitor KN93 partially blocked K+-stimulated transcription of NGFIB and NURR1. KN93 partially inhibited the effect of Ang II on NURR1 mRNA levels but did not modify the effect on expression of NGFIB. Mutation of the NBRE-1, Ad5, and Ad1/cAMP response element (CRE) cis-elements reduced both basal and Ang II-induced levels of hCYP11B2, demonstrating that all three elements are important for maximal transcriptional activity. Our results suggest that NGFIB and NURR1 are key regulators of hCYP11B2 expression and may partially mediate the regulation of hCYP11B2 by Ang II.
Characterization of the pufferfishOtx2cis-regulators reveals evolutionarily conserved genetic mechanisms for vertebrate head specification
Authors: Kimura-Yoshida Chiharu , Kitajima Kuniko , Oda-Ishii Izumi , Tian E , Suzuki Misao , Yamamoto Masayuki , Suzuki Tohru , Kobayashi Makoto , Aizawa Shinichi , Matsuo Isao
Published: December 2003

The Otx2 gene, containing a highly conserved paired-type homeobox, plays a pivotal role in the development of the rostral head throughout vertebrates. Precise regulation of the temporal and spatial expression of Otx2 is likely to be crucial for proper head specification. However, regulatory mechanisms of Otx2 expression remain largely unknown. In this study, the Otx2 genome of the puffer fish Fugu rubripes, which has been proposed as a model vertebrate owing to its highly compact genome, was cloned. Consistently, Fugu Otx2 possesses introns threefold smaller in size than those of the mouse Otx2 gene. Otx2 mRNA was transcribed after MBT, and expressed in the rostral head region throughout the segmentation and pharyngula periods of wild-type Fugu embryos. To elucidate regulatory mechanisms of Otx2 expression, the expression of Otx2-lacZreporter genes nearly covering the Fugu Otx2 locus, from –30.5 to +38.5 kb, was analyzed, by generating transgenic mice. Subsequently, seven independent cis-regulators were identified over an expanse of 60 kb; these regulators are involved in the mediation of spatiotemporally distinct subdomains of Otx2 expression. Additionally, these expression domains appear to coincide with local signaling centers and developing sense organs. Interestingly, most domains do not overlap with one another, which implies that cis-regulators for redundant expression may be abolished exclusively in the pufferfish so as to reduce its genome size. Moreover, these cis-regions were also able to direct expression in zebrafish embryos equivalent to that observed in transgenic mice. Further comparative sequence analysis of mouse and pufferfish intergenic regions revealed eight highly conserved elements within these cis-regulators. Therefore, we propose that, in vertebrate evolution, the Otx2 promoter acquires multiple, spatiotemporally specific cis-regulators in order to precisely control highly coordinated processes in head development.
Retinoic acid regulates a subset of Cdx1 function in vivo
Authors: Houle Martin , Sylvestre Jean-René , Lohnes David
Published: December 2003

Hox gene products are key players in establishing positional identity along the anteroposterior (AP) axis. In vertebrates, gain or loss of Hox expression along the AP axis often leads to inappropriate morphogenesis, typically manifesting as homeotic transformations that affect the vertebrae and/or hindbrain. Various signalling pathways are known to impact on Hox expression,including the retinoid signalling pathway. Exogenous retinoic acid (RA),disruption of enzymes involved in maintaining normal embryonic RA distribution or mutation of the retinoid receptors (RARs and RXRs) can all impact on Hox expression with concomitant effects on AP patterning.

Several Hox loci have well characterized RA response elements (RAREs),which have been shown to regulate functionally relevant Hox expression in the neurectoderm. A similar crucial function for any RARE in mesodermal Hox expression has, however, not been documented. The means by which RA regulates mesodermal Hox expression could therefore be either through an undocumented direct mechanism or through an intermediary; these mechanisms are not necessarily exclusive. In this regard, we have found that Cdx1 may serve as such an intermediary. Cdx1 encodes a homeobox transcription factor that is crucial for normal somitic expression of several Hox genes, and is regulated by retinoid signalling in vivo and in vitro likely through an atypical RARE in the proximal promoter. In order to more fully understand the relationship between retinoid signalling, Cdx1 expression and AP patterning, we have derived mice in which the RARE has been functionally inactivated. These RARE-null mutants exhibit reduced expression of Cdx1 at all stages examined, vertebral homeotic transformations and altered Hox gene expression which correlates with certain of the defects seen in Cdx1-null offspring. These findings are consistent with a pivotal role for retinoid signalling in governing a subset of expression of Cdx1 crucial for normal vertebral patterning.
Wingless and Notch signaling provide cell survival cues and control cell proliferation during wing development
Authors: Giraldez Antonio J. , Cohen Stephen M.
Published: December 2003

Tissue growth during animal development depends on the coordination of cell proliferation and cell death. The EGF-receptor/MAPK, Hedgehog, Dpp, Wingless(Wg) and Notch signaling pathways have been implicated in growth control in the developing Drosophila wing. In this report, we examine the effects of Notch and Wg on growth in terms of cell proliferation and cell survival. Reduction of Wg signaling impaired compartment and clonal growth,and increased cell death. Inhibition of apoptosis in cells deficient for Wg signaling only partially rescued the clone growth defect, suggesting that Wg is also required to promote cell proliferation. This is supported by the finding that ectopic expression of Wg caused over-proliferation of cells in the proximal wing. Localized activation of Notch had non-autonomous effects on cell proliferation. However, only part of this effect was attributable to Notch-dependent induction of Wg, suggesting that other Notch-inducible signaling molecules contribute to the control of cell proliferation in the wing.
Death is the major fate of medial edge epithelial cells and the cause of basal lamina degradation during palatogenesis
Authors: Cuervo Rodrigo , Covarrubias Luis
Published: December 2003

During mammalian development, a pair of shelves fuses to form the secondary palate, a process that requires the adhesion of the medial edge epithelial tissue (MEE) of each shelf and the degeneration of the resulting medial epithelial seam (MES). It has been reported that epithelialmesenchymal transformation (EMT) occurs during shelf fusion and is considered a fundamental process for MES degeneration. We recently found that cell death is a necessary process for shelf fusion. These findings uncovered the relevance of cell death in MES degeneration; however, they do not discard the participation of other processes. In the present work, we focus on the evaluation of the processes that could contribute to palate shelf fusion. We tested EMT by traditional labeling of MEE cells with a dye, by infection of MEE with an adenovirus carrying the lacZ gene, and by fusing wild-type shelves with the ones from EGFP-expressing mouse embryos. Fate of MEE labeled cells was followed by culturing whole palates, or by a novel slice culture system that allows individual cells to be followed during the fusion process. Very few labeled cells were found in the mesenchyme compartment, and almost all were undergoing cell death. Inhibition of metalloproteinases prevented basal lamina degradation without affecting MES degeneration and MEE cell death. Remarkably, independently of shelf fusion,activation of cell death promoted the degradation of the basal lamina underlying the MEE (`cataptosis'). Finally, by specific labeling of periderm cells (i.e. the superficial cells that cover the basal epithelium), we observed that epithelial triangles at oral and nasal ends of the epithelial seam do not appear to result from MEE cell migration but rather from periderm cell migration. Inhibition of migration or removal of these periderm cells suggests that they have a transient function controlling MEE cell adhesion and survival, and ultimately die within the epithelial triangles. We conclude that MES degeneration occurs almost uniquely by cell death, and for the first time we show that this process can activate basal lamina degradation during a developmental process.
ThreeDrosophilaEXT genes shape morphogen gradients through synthesis of heparan sulfate proteoglycans
Authors: Takei Yuki , Ozawa Yutakahiko , Sato Makoto , Watanabe Akira , Tabata Tetsuya
Published: December 2003

The signaling molecules Hedgehog (Hh), Decapentaplegic (Dpp) and Wingless(Wg) function as morphogens and organize wing patterning in Drosophila. In the screen for mutations that alter the morphogen activity, we identified novel mutants of two Drosophila genes, sister of tout-velu (sotv) and brother of tout-velu(botv), and new alleles of toutvelu (ttv). The encoded proteins of these genes belong to an EXT family of proteins that have or are closely related to glycosyltransferase activities required for biosynthesis of heparan sulfate proteoglycans (HSPGs). Mutation in any of these genes impaired biosynthesis of HSPGs in vivo, indicating that, despite their structural similarity, they are not redundant in the HSPG biosynthesis. Protein levels and signaling activities of Hh, Dpp and Wg were reduced in the cells mutant for any of these EXT genes to a various degree, Wg signaling being the least sensitive. Moreover, all three morphogens were accumulated in the front of EXT mutant cells, suggesting that these morphogens require HSPGs to move efficiently. In contrast to previous reports that ttv is involved exclusively in Hh signaling, we found that ttv mutations also affected Dpp and Wg. These data led us to conclude that each of three EXT genes studied contribute to Hh, Dpp and Wg morphogen signaling. We propose that HSPGs facilitate the spreading of morphogens and therefore, function to generate morphogen concentration gradients.
rigor mortisencodes a novel nuclear receptor interacting protein required for ecdysone signaling duringDrosophilalarval development
Authors: Gates Julie , Lam Geanette , Ortiz José A. , Losson Régine , Thummel Carl S.
Published: December 2003

Pulses of the steroid hormone ecdysone trigger the major developmental transitions in Drosophila, including molting and puparium formation. The ecdysone signal is transduced by the EcR/USP nuclear receptor heterodimer that binds to specific response elements in the genome and directly regulates target gene transcription. We describe a novel nuclear receptor interacting protein encoded by rigor mortis (rig) that is required for ecdysone responses during larval development. rig mutants display defects in molting, delayed larval development, larval lethality, duplicated mouth parts, and defects in puparium formation – phenotypes that resemble those seen in EcR, usp, E75A and βFTZ-F1mutants. Although the expression of these nuclear receptor genes is essentially normal in rig mutant larvae, the ecdysone-triggered switch in E74 isoform expression is defective. rig encodes a protein with multiple WD-40 repeats and an LXXLL motif, sequences that act as specific protein-protein interaction domains. Consistent with the presence of these elements and the lethal phenotypes of rig mutants, Rig protein interacts with several Drosophila nuclear receptors in GST pull-down experiments, including EcR, USP, DHR3, SVP and βFTZ-F1. The ligand binding domain of βFTZ-F1 is sufficient for this interaction, which can occur in an AF-2-independent manner. Antibody stains reveal that Rig protein is present in the brain and imaginal discs of second and third instar larvae,where it is restricted to the cytoplasm. In larval salivary gland and midgut cells, however, Rig shuttles between the cytoplasm and nucleus in a spatially and temporally regulated manner, at times that correlate with the major lethal phase of rig mutants and major switches in ecdysone-regulated gene expression. Taken together, these data indicate that rig exerts essential functions during larval development through gene-specific effects on ecdysone-regulated transcription, most likely as a cofactor for one or more nuclear receptors. Furthermore, the dynamic intracellular redistribution of Rig protein suggests that it may act to refine spatial and temporal responses to ecdysone during development.
Finger or toe: the molecular basis of limb identity
Authors: Logan Malcolm
Published: December 2003

Despite their obvious similarities, the forelimbs and hindlimbs of tetrapod vertebrates have evolved distinct structural elements to carry out their discrete functions. Many genes required for limb initiation and patterning are involved in regulatory networks common to both limb-types. Other genes are differentially expressed between forelimb and hindlimb, and have been implicated in the initiation of limb bud outgrowth and the specification of limb-type identity. In this review, I will discuss the current understanding of how genes that control limb identity interact with regulatory networks common to both appendages to produce the fingers of the hand and toes of the foot.
TheS. cerevisiaeHtrA-like protein Nma111p is a nuclear serine protease that mediates yeast apoptosis
Authors: Fahrenkrog Birthe , Sauder Ursula , Aebi Ueli
Published: December 2003

The yeast S. cerevisiae can undergo programmed cell death that exhibits the typical cellular markers of apoptosis. The mammalian HtrA2 protein was recently reported to mediate apoptosis in a serine-protease-dependent manner owing to its ability to antagonise the inhibitor of apoptosis protein XIAP. Here, we report the identification and characterisation of the S. cerevisiae HtrA-like protein, which we termed Nma111p (for nuclear mediator of apoptosis), as a mediator of yeast apoptosis. Nma111p is a nuclear protein that, under cellular stress conditions (i.e. at elevated temperature or after induction of apoptosis by H2O2), tends to aggregate inside the nucleus without its expression level being upregulated, suggesting that aggregation of Nma111p is correlated to its death-mediating character. Nma111p belongs to the HtrA family of serine proteases and its pro-apoptotic activity depends on its serine-protease activity. Yeast cells that lack Nma111p survive better at 50°C than wild-type cells and the cells show no apoptotic hallmarks, such as chromatin condensation and fragmentation, or accumulation of reactive oxygen species, after the induction of apoptosis by H2O2. By contrast, overexpression of Nma111p enhances apoptotic-like cell death. Therefore, Nma111p, like its mammalian homologue HtrA2, mediates apoptosis.