Signatures of the Optical Stark Effect on Entangled Photon Pairs from Resonantly Pumped Quantum Dots

Two-photon resonant excitation of the biexciton-exciton cascade in a quantum dot generates highly polarization-entangled photon pairs in a near-deterministic way. However, the ultimate level of achievable entanglement is still debated. Here, we observe the impact of the laser-induced ac-Stark effect on the quantum dot emission spectra and on entanglement. For increasing pulse-duration-to-lifetime ratios and pump powers, decreasing values of concurrence are recorded. Nonetheless, additional contributions are still required to fully account for the observed below-unity concurrence.

Measured proton electromagnetic structure deviates from theoretical predictions

The visible world is founded on the proton, the only composite building block of matter that is stable in nature. Consequently, understanding the formation of matter relies on explaining the dynamics and the properties of the proton's bound state. A fundamental property of the proton involves the response of the system to an external electromagnetic field. It is characterized by the electromagnetic polarizabilities¹ that describe how easily the charge and magnetization distributions inside the system are distorted by the electromagnetic field. Moreover, the generalized polarizabilities² map out the resulting deformation of the densities in a proton subject to an electromagnetic field. They disclose essential information about the underlying system dynamics and provide a key for decoding the proton structure in terms of the theory of the strong interaction that binds its elementary quark and gluon constituents. Of particular interest is a puzzle in the electric generalized polarizability of the proton that remains unresolved for two decades². Here we report measurements of the proton's electromagnetic generalized polarizabilities at low four-momentum transfer squared. We show evidence of an anomaly to the behaviour of the proton's electric generalized polarizability that contradicts the predictions of nuclear theory and derive its signature in the spatial distribution of the induced polarization in the proton. The reported measurements suggest the presence of a new, not-yet-understood dynamical mechanism in the proton and present notable challenges to the nuclear theory.

Deeply Virtual Compton Scattering Cross Section at High Bjorken x_{B}

We report high-precision measurements of the deeply virtual Compton scattering (DVCS) cross section at high values of the Bjorken variable x_{B}. DVCS is sensitive to the generalized parton distributions of the nucleon, which provide a three-dimensional description of its internal constituents. Using the exact analytic expression of the DVCS cross section for all possible polarization states of the initial and final electron and nucleon, and final state photon, we present the first experimental extraction of all four helicity-conserving Compton form factors (CFFs) of the nucleon as a function of x_{B}, while systematically including helicity flip amplitudes. In particular, the high accuracy of the present data demonstrates sensitivity to some very poorly known CFFs.

P200 ISCHEMIC HEART IN PAZIENTS UNDER 30: AN UNSOLVED CHELLENGE

Background

The pathogenesis of ischemic heart disease (IHD) in young patients is still unclear. Several studies have demonstrated the existence of peculiar cardiovascular risk factors (CRFs) that differ from the typical factors involved in the more common IHD of adults.Plaque rupture represents the most common etiology of myocardial infarction (MI), nonetheless, other events can play a role in young patients affected by IHD, including coronary artery plaque erosion, coronary microvascular dysfunction, spontaneous dissection of the coronary artery, and coronary artery spasm secondary to drug abuse. Due to the differences in the clinical manifestations, diagnosis, and therapeutic management, further research is needed to study the profile of MI in young patients1

Clinical Case

A 28–year–old male, occasional smoker, negative familiar anamnesis for IHD. His past medical history was significant for an acute coronary syndrome (ACS) STEMI at the age of 20 years old, treated with percutaneous transluminal coronary angioplasty (PTCA) with scaffold in the interventricular anterior artery (IVA). After 7 years he was admitted following a thrombotic occlusion of the IVA, managed with PTCA/ drug–eluting stent (DES) followed by coronary artery bypass surgery diverting the blood flow of the IVA in the left internal mammary artery (IMA). After only 11 months he presented with a new ACS NSTEMI treated with PTCA/DES of the IVA in the left IMA. No biochemical signs of coagulopathy or peripheral artery disease were disclosed, and the supra–aortic trunks resulted normal. Nevertheless, a significant increase in the blood levels of homocysteine and slightly elevated values of fibrinogen, D–dimers, and C–reactive protein. Erythrocyte sedimentation rate resulted within the physiological ranges.

Discussion and Conclusion

The peculiar medical history of the described patient suggests a marked tendency not only for the formation and plaque rupture but also for platelet aggregation. The only significant and persistent values that were found to be elevated were homocysteine and inflammatory markers. One–year follow–up examination revealed complete regression of the symptoms with double antiaggregating therapy and supplements of folic acid. The rarity of such cases should prompt new research to better understand IHD in this population and possible targeted treatments Acute Myocardial Infarction in Young Individuals; Rajiv Gulati; Mayo Clinic Proceedings, V 95, I. 1, P136–156, 2020.

Form Factors and Two-Photon Exchange in High-Energy Elastic Electron-Proton Scattering

We present new precision measurements of the elastic electron-proton scattering cross section for momentum transfer (Q^{2}) up to 15.75  (GeV/c)^{2}. Combined with existing data, these provide an improved extraction of the proton magnetic form factor at high Q^{2} and double the range over which a longitudinal or transverse separation of the cross section can be performed. The difference between our results and polarization data agrees with that observed at lower Q^{2} and attributed to hard two-photon exchange (TPE) effects, extending to 8  (GeV/c)^{2} the range of Q^{2} for which a discrepancy is established at >95% confidence. We use the discrepancy to quantify the size of TPE contributions needed to explain the cross section at high Q^{2}.

Deep Exclusive Electroproduction of π^{0} at High Q^{2} in the Quark Valence Regime

We report measurements of the exclusive neutral pion electroproduction cross section off protons at large values of x_{B} (0.36, 0.48, and 0.60) and Q^{2} (3.1 to 8.4  GeV^{2}) obtained from Jefferson Lab Hall A experiment E12-06-014. The corresponding structure functions dσ_{T}/dt+εdσ_{L}/dt, dσ_{TT}/dt, dσ_{LT}/dt, and dσ_{LT^{'}}/dt are extracted as a function of the proton momentum transfer t-t_{min}. The results suggest the amplitude for transversely polarized virtual photons continues to dominate the cross section throughout this kinematic range. The data are well described by calculations based on transversity generalized parton distributions coupled to a helicity flip distribution amplitude of the pion, thus providing a unique way to probe the structure of the nucleon.

Effect of Behaviorally Designed Gamification With a Social Support Partner to Increase Mobility After Hospital Discharge: A Randomized Clinical Trial

IMPORTANCE

Hospitalization is associated with decreased mobility and functional decline. Behaviorally designed gamification can increase mobility in community settings but has not been tested among patients at risk for functional decline during a high-risk transition period after hospitalization.

OBJECTIVE

To test a behaviorally designed gamification intervention with a social support partner to increase patient mobility after hospital discharge.

DESIGN, SETTING, AND PARTICIPANTS

This study is a randomized clinical trial of a 12-week intervention without follow-up. Enrollment occurred from January 2018 to June 2019 at a referral hospital with a remote at-home monitoring intervention among patients living predominantly in 3 states (Pennsylvania, New Jersey, and Delaware). Participants included adult patients discharged from general medicine and oncology units to home. Data analysis was performed from October 2019 to March 2020.

INTERVENTIONS

All participants received a wearable device to track daily steps. The control group received feedback from the device but no other interventions. The intervention group entered into a 12-week game informed by behavioral economics to assign points and levels for achieving step goals and reinforced by a support partner who received updates on participant progress.

MAIN OUTCOMES AND MEASURES

The primary outcome was change in mean daily steps from baseline through the 12-week intervention. Secondary measures were change in functional status and urgent care utilization (ie, emergency department visits and hospital readmissions) within this period.

RESULTS

A total of 232 participants were enrolled in the study (118 randomized to control and 114 randomized to the intervention). Participants had a mean (SD) age of 40 (14) years, 141 (61%) were female, 101 (43%) were White, and 103 (44%) had an annual household income less than $50 000. Daily step counts increased from 3795 to 4652 steps (difference, 857 steps; 95% CI, 488 to 1224 steps) among intervention participants and increased from 3951 to 4499 steps (difference, 548 steps; 95% CI, 193 to 903 steps) among control participants. The change in mean daily step count from baseline was not significantly different for participants in the intervention group vs the control group (adjusted difference, 270 steps; 95% CI, -214 to 754 steps; P = .27). Among the subgroup of 76 participants with higher levels of social engagement, post hoc exploratory analyses showed a significant increase in mobility for intervention vs control (adjusted difference, 1125 steps; 95% CI, 409 to 1841 steps; P = .002). Fewer participants in this subgroup experienced functional decline (1 of 36 participants [4%] in the intervention group vs 5 of 40 participants [12%] in the control group) and hospital readmission at 30 days (3 of 36 participants [8%] in the intervention group vs 6 of 40 participants [15%] in the control group), but the differences were not statistically significant. There were no significant differences in these secondary outcomes for the overall sample.

CONCLUSIONS AND RELEVANCE

Gamification with social incentives did not affect mobility or functional decline in all participants, but post hoc analysis suggests positive findings for both outcomes for patients with higher social engagement.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03321279.

Ruling out Color Transparency in Quasielastic ^{12}C(e,e^{'}p) up to Q^{2} of 14.2 (GeV/c)^{2}

Quasielastic ^{12}C(e,e^{'}p) scattering was measured at spacelike 4-momentum transfer squared Q^{2}=8, 9.4, 11.4, and 14.2  (GeV/c)^{2}, the highest ever achieved to date. Nuclear transparency for this reaction was extracted by comparing the measured yield to that expected from a plane-wave impulse approximation calculation without any final state interactions. The measured transparency was consistent with no Q^{2} dependence, up to proton momenta of 8.5  GeV/c, ruling out the quantum chromodynamics effect of color transparency at the measured Q^{2} scales in exclusive (e,e^{'}p) reactions. These results impose strict constraints on models of color transparency for protons.

Clinical profile and in-hospital course of patients with primary and secondary takotsubo syndrome: single center experience

Background

Takotsubo syndrome (TTS) is an acute cardiac disease increasingly recognized in a variety of clinical scenarios. Heart Failure Association of the ESC classified TTS in primary (occurring in the setting of psychological or emotional trigger or without clear identifiable stressors) and secondary (triggered by physical stressors or other critical illnesses). However, the clinical profile and outcome of these different subtypes is still controversial.

Aim of the study

To compare baseline features, clinical presentation and in-hospital outcomes in patients with primary or secondary TTS in a single referral center.

Methods

Overall study population included 210 patients (mean age 66.1±12.2 years, 14 male); 165 and 45 with primary and secondary TTS, respectively; consecutively enrolled from 2012 to 2019 in our center. Clinical, instrumental and laboratory data and in-hospital events were also recorded in both groups.

Results

Compared to patients with primary TTS, patients with secondary form were older (70.6±14.6 vs 64.9±11.2 years; p=0.006) and more frequently man (13.3% vs 4.8%; p=0.043). Several comorbidities such as diabetes (23.8% vs 8.9%; p=0.008); pulmonary (45.2% vs 12.9%; p<0.001); neurologic (23.8% vs 9.7%; p=0.015); nephro-urologic (31% vs 13.5%; p=0.008); psychiatric (42.9% vs 26.5%; p=0.039) and orthopedic (28.6% vs 13.5%; p=0.020) diseases were prevalent in secondary TTS patients. Atypical presentation with higher incidence of dyspnea was significantly prevalent (42.2% vs 19.4%; p=0.002) in secondary group. The number of patients with ST-T elevation on admission was similar (80% vs 77%; p=0.5) in both groups. Prolonged QT interval in a majority of secondary TTS patients (46.3% vs 28.4%; p=0.029) was detected. Peak levels of troponin, creatine-kinase and myoglobin did not differ between the two groups. Echocardiography revealed larger left ventricular end-diastolic and end-systolic volumes (62.7±25.3 vs 50.6±14.3 ml/mq; p=0.024 and 35.1±14.5 vs 28.7±9 ml/mq; p=0.048) at presentation in secondary TTS, however no differences in baseline left ventricular ejection fraction were detected. Furthermore, the prevalence of apical ballooning was similar between the two groups. Of note, secondary TTS patients experienced more frequently acute heart failure (40.5% vs 23.1%; p=0.024), hyperkinetic arrhythmia (9.1% vs 1.9%; p=0.022), cardiogenic shock (15.9% vs 3.2%; p=0.002), and mechanical ventilation use (9.3% vs 1.3%; p=0.006) during the acute phase. In-hospital stay (10.8±6.9 vs 7.4±6.2 days, p=0.004) was longer in this cohort.

Conclusion

Our results demonstrate that to classify TTS patients in primary or secondary form is clinically relevant. Secondary form generally is associated to higher rate of comorbidities and to atypical presentation. Owing to the worse in-hospital outcome of the secondary TTS patients a tailored and more intensive treatment should be adopted in this cohort.

Funding Acknowledgement

Type of funding source: None

Views From Patients With Cancer in the Setting of Unplanned Acute Care: Informing Approaches to Reduce Health Care Utilization

PURPOSE

New oncology care delivery models that avoid preventable acute care are needed, yet it is unclear which interventions best meet the needs of patients and caregivers. Perspectives from patients who experienced unplanned acute care events may inform the successful development and implementation of care delivery models.

METHODS

We performed a qualitative interview study of patients with solid tumors on active treatment who experienced the following 3 types of unplanned acute care events: emergency department visits, first hospitalizations, and multiple hospitalizations. Patients were prospectively recruited within a large academic health system from August 2018 to January 2019. Interviews followed a semi-structured guide developed from the Consolidated Framework for Implementation Research. The constant comparative approach was used to identify themes.

RESULTS

Forty-nine patients were interviewed; 51% were men, 75% were non-Hispanic White, and the mean age was 57.4 years (standard deviation, 1.9 years). Fifty-five percent of patients had metastatic disease, and 33% had an Eastern Cooperative Oncology Group performance status of 3-4. We identified the following key themes: drivers of the decision to seek acute care, patients' emotional concerns that influence interactions with the oncology team, and strategies used to avoid acute care. Patients' recommendations for interventions included anticipatory guidance, peer support, improved triage methods, and enhanced symptom management. Patients preferred options for virtual and home-based outpatient care.

CONCLUSION

Patient-centered care models should focus on early delivery of supportive interventions that help patients and caregivers navigate the unexpected issues that come with cancer treatment. Patients advocate for proactive, multidisciplinary supportive interventions that enable home-based care and are led by the primary oncology team.

P322 Dynamic changes of left ventricular cardiac mechanics in takotsubo syndrome: a preliminary study

Background

Takotsubo syndrome (TTS) is a transient left ventricular (LV) heart failure due to a reversible systolic dysfunction, usually recovering within days or weeks.

Purpose

To assess the dynamic changes of LV cardiac mechanics in a small cohort of TTS patients through the estimation of myocardial work, a newly developed non-invasive approach which allows correction of global longitudinal strain (GLS) for systolic blood pressure.

Methods

Twenty-four patients (mean age, 63.8 ± 8.4 yy; all female) with TTS diagnosis were retrospectively enrolled. Data from transthoracic two-dimensional and speckle-tracking echocardiography on admission and at 3 months follow-up were collected. Global myocardial work index (GWI, mmHg%) was calculated as the area of the LV pressure (LVP)-strain loop, where LVP was estimated noninvasively using a standard waveform fitted to valvular events and scaled to systolic blood pressure. From GWI we also assessed: global constructive work (GCW, mmHg%: work performed during shortening in systole + negative work during lenghtening in isovolumetric relaxation, IVR), global wasted work (GWW, mmHg%: negative workperformed by a segment during lengthening in systole + work performed during shortening in IVR) and global work efficiency (GWE, %: constructive work divided by the sum of constructive and wasted work). Baseline demographic and clinical features, including in-hospital adverse events as acute heart failure, cardiogenic shock and cardiac death, were also assessed.

Results

On overall population, a reduced ejection fraction (EF) and GLS were detected at hospital admission, with a substantial improvement at discharge and at follow-up (from 41.7 ± 8.3% to 54.5 ± 6.5% to 60.2 ± 4.6% for EF and from -11.7 ± 4.5% to -16.2 ± 4.2 to -21.3 ± 2.8% for GLS, respectively). Similarly, global MWI and MWE both showed a positive trend during the hospital course and at follow-up: MWI increased from 1048.8 ± 580.5 to 1522.4 ± 695.4 to 2021.1 ± 388.6 mmHg% and MWE from 78.7 ± 10.2 to 91.1 ± 4.6 to 94.5 ± 3.8 %. Increasing in MWE has been obtained through an improvement of GCW (from 1195.9 ± 537.2 to 1651.3 ± 700.3 to 2316.8 ± 490.6 mmHg%) and a contemporary decreasing in GWW (from 237.9 ± 137.2 to 106 ± 37.2 to 131.8 ± 150.8 mmHg%).

In-hospital adverse events occurred in 8 (50%) patients. Of note, despite EF and GLS at admission showed no significant differences, patients experiencing in-hospital adverse events showed lower value of acute MWI (725.6 ± 289.6 vs 1371.9 ± 632.1 mmHg%; p= 0.02) and MWE (73.6 ± 3.4 vs 83.8 ± 12.4%; p= 0.04) compared to patients without in-hospital complications.

Conclusion

Non-invasive assessment of myocardial work through echocardiographic strain-based technique could be useful to demonstrate the peculiar dynamic changes of cardiac mechanics and for a better risk stratification in TTS patients.

Abstract P322 Figure.

Entanglement Swapping with Photons Generated on Demand by a Quantum Dot

Photonic entanglement swapping, the procedure of entangling photons without any direct interaction, is a fundamental test of quantum mechanics and an essential resource to the realization of quantum networks. Probabilistic sources of nonclassical light were used for seminal demonstration of entanglement swapping, but applications in quantum technologies demand push-button operation requiring single quantum emitters. This, however, turned out to be an extraordinary challenge due to the stringent prerequisites on the efficiency and purity of the generation of entangled states. Here we show a proof-of-concept demonstration of all-photonic entanglement swapping with pairs of polarization-entangled photons generated on demand by a GaAs quantum dot without spectral and temporal filtering. Moreover, we develop a theoretical model that quantitatively reproduces the experimental data and provides insights on the critical figures of merit for the performance of the swapping operation. Our theoretical analysis also indicates how to improve state-of-the-art entangled-photon sources to meet the requirements needed for implementation of quantum dots in long-distance quantum communication protocols.

Perspectives on cancer care delivery from oncology patients who experienced unplanned acute care events

201

Background: Unplanned acute care is debilitating and burdensome for patients with advanced cancer and their caregivers. There is a pressing need to understand how available evidence-based practices (EBPs) to reduce acute care 1) align with the needs and priorities of patients and 2) are best implemented within large health systems. We are conducting a mixed methods study to assess patient- provider- and system-level factors that shape the decision to seek acute care during active cancer treatment in order to select and adapt EBPs for implementation. Here we present data from patients’ perspectives. Methods: Purposive sampling approach to identify solid tumor cancer patients on active treatment with unplanned acute care events at a large health system from Aug 2018-Jan 2019. We conducted semi-structured interviews to elicit patients’ perspectives on factors that shape their decision to seek acute care and to inform intervention strategies. Results: Forty-nine patients participated in this study. We identify several patient factors that intersect with the decision to seek care: self-management behaviors, guilt, negative ED perception, safety concerns, and trust. Patients attempt self-management prior to contacting their oncology team, which introduces variability in the duration and severity of reported symptoms. Delay is related to patients’ guilt for burdening their oncology team and to provider accessibility. Patients describe a high symptom threshold to seek care that is often coupled with a negative perception of the ED, but do prefer in-person evaluation for new and distressing symptoms for safety. They express a high level of trust in the oncology team and relative distrust of non-oncology providers. Conclusions: Our data suggest a conceptual model for patient factors that drive unplanned acute care. Patients identify three areas for improvement: 1) enhanced peer support and education to manage uncertainty about cancer treatment; 2) accessible portals for patient-clinician communication; and 3) home or clinic-based after-hours oncology symptom management. Interventions to target these needs should address patients’ emotional concerns and be well integrated within the oncology team.

Patient factors that drive unplanned acute care utilization in oncology care

e18011

Background: There is a critical need to develop oncology care delivery models that help cancer patients avoid preventable acute hospital care. We are conducting a mixed methods study to assess patient- provider- and system-level factors that drive unplanned acute care utilization in order to implement evidence-based practices (EBPs) at a large health system. Here we present data from patient perspectives on the factors that influence their decision to seek acute care. Methods: We used a purposive sampling approach to identify cancer patients with solid tumors on active treatment with unplanned acute care events at an academic cancer center or its two affiliated community practices from August 2018-January 2019. We conducted semi-structured interviews designed to elicit patient factors that drive unplanned acute care utilization and to understand strategies patients use to manage unexpected symptoms at home. Interviews were analyzed using the constant comparative method to identify key themes. Results: Forty-three patients participated in this study. We identify several patient factors that intersect with the decision to seek care: self-management behaviors, guilt, negative ED perception, safety concerns, and trust. Patients attempt self-management prior to contacting their oncology team, which introduces variability in the duration and severity of reported symptoms. Delay is related to patients’ sense of guilt for burdening their oncology team and to differences in provider accessibility. Patients describe a high symptom threshold to seek care that is often coupled with a negative perception of the ED. However, due to safety concerns, patients do prefer in-person evaluation for new and distressing symptoms. They also express a high level of trust in the oncology team and relative distrust of non-oncology providers. Conclusions: Our data suggest a conceptual model for patient factors that drive unplanned acute care and identify the following targets for implementation of EBPs: 1) symptom management 2) provider accessibility 3) alternate triage pathways for in-person evaluation. Strategies to target these needs should address patients’ emotional concerns and be well integrated within the oncology team.

Reducing disability via a family centered intervention for acutely ill persons with Alzheimer's disease and related dementias: protocol of a cluster-randomized controlled trial (Fam-FFC study)

Background

Hospitalized older persons with Alzheimer’s disease and related dementias are at greater risk for functional decline and increased care dependency after discharge due to a combination of intrinsic factors, environmental, policy, and care practices that restrict physical and cognitive activity, lack of family involvement and limited staff knowledge of dementia care. We have developed a theory-based intervention, Family centered Function-focused Care, that incorporates an educational empowerment model for family caregivers (FCGs) provided within a social-ecological framework to promote specialized care to patients with dementia during hospitalization and the 60-day post-acute period. Primary aims are to test the efficacy of the intervention in improving physical and cognitive recovery in hospitalized persons living with Alzheimer’s disease and related dementias (ADRD) and improving FCG preparedness and experiences.

Method

We will implement Family centered Function-focused Care in a cluster-randomized trial of 438 patient/FCG dyads in six hospital units randomized within three hospitals. We hypothesize that patients who receive the intervention will demonstrate better physical function, less delirium occurrence and severity, neuropsychiatric symptoms, and depression compared to those in the control condition (Education-only). We also hypothesize that FCGs enrolled in Family centered Function-focused Care will experience increased preparedness for caregiving, and less strain, burden, and desire to institutionalize, as compared to FCGs the control group. We will also examine the costs and relative cost savings associated with the intervention and will evaluate the cultural appropriateness of Family centered Function-focused Care for families from diverse backgrounds.

Discussion

Our theory-based intervention makes use of real-world applicable approaches in a novel and innovative way to change the paradigm of how we currently look at acute care and post-acute transitions in persons with ADRD.

Trial registration

ClinicalTrials.gov, ID: NCT03046121. Registered on 8 February 2017.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-2875-1) contains supplementary material, which is available to authorized users.

BAYESIAN ANALYSIS OF COSMIC RAY PROPAGATION: EVIDENCE AGAINST HOMOGENEOUS DIFFUSION

We present the results of the most complete scan of the parameter space for cosmic ray (CR) injection and propagation. We perform a Bayesian search of the main GALPROP parameters, using the MultiNest nested sampling algorithm, augmented by the BAMBI neural network machine-learning package. This is the first study to separate out low-mass isotopes (p, p ¯ , and He) from the usual light elements (Be, B, C, N, and O). We find that the propagation parameters that best-fit p, p ¯ , and He data are significantly different from those that fit light elements, including the B/C and 10Be/9Be secondary-to-primary ratios normally used to calibrate propagation parameters. This suggests that each set of species is probing a very different interstellar medium, and that the standard approach of calibrating propagation parameters using B/C can lead to incorrect results. We present posterior distributions and best-fit parameters for propagation of both sets of nuclei, as well as for the injection abundances of elements from H to Si. The input GALDEF files with these new parameters will be included in an upcoming public GALPROP update.

Challenges in recruiting subjects to a pilot trial of patient-managed in-hospital insulin

Background

To examine the feasibility of implementing clinician-supported inpatient self-managed insulin to aid in the planning of a randomized clinical trial.

Results

We conducted a proof-of-concept interventional study of inpatients with diabetes mellitus who had hospital orders for basal-bolus or sliding scale insulin. Patients meeting inclusion criteria were offered the opportunity to manage their own basal-bolus insulin with support from a diabetes nurse practitioner. Over a three-month screening period, we conducted 361 screens in 336 patients, only eleven of whom met all inclusion criteria. None of these eleven eligible patients elected to enroll. The most common reason for refusal was lack of interest in self-managing insulin while acutely ill (36 %).

Discussion

Future studies of patient-managed in-hospital insulin should consider enrolling less acutely ill patients with longer anticipated lengths of stay.

Trials registration: NCT02144441

Combating compassion fatigue: an exemplar of an approach to nursing renewal

Compassion fatigue is a phenomenon commonly experienced by nurses. The cumulative emotional burden of caring for critically ill patients and their families, coupled with the increasing complexity of the health care practice environment, significantly drives the experience of compassion fatigue. Compassion fatigue can negatively impact nurses' physical and emotional well-being. If left unaddressed, compassion fatigue can lead to burnout among nurses. Burnout has been correlated to increased patient mortality, increased infection rates, and decreased patient satisfaction. In addition, it causes nurses to leave the nursing profession. Opportunities for nursing renewal, coupled with a leadership culture that values renewal practices, could combat the negative effects of compassion fatigue. A Center for Nursing Renewal was created at the Hospital of the University of Pennsylvania in Philadelphia, Pennsylvania, to provide a variety of renewal opportunities for nurses. This center is supported by a nursing culture that recognizes the ill effects of compassion fatigue and promotes wellness and renewal practices among nurses.

Universal recovery of the energy-level degeneracy of bright excitons in InGaAs quantum dots without a structure symmetry

The lack of structural symmetry which usually characterizes semiconductor quantum dots lifts the energetic degeneracy of the bright excitonic states and hampers severely their use as high-fidelity sources of entangled photons. We demonstrate experimentally and theoretically that it is always possible to restore the excitonic degeneracy by the simultaneous application of large strain and electric fields. This is achieved by using one external perturbation to align the polarization of the exciton emission along the axis of the second perturbation, which then erases completely the energy splitting of the states. This result, which holds for any quantum dot structure, highlights the potential of combining complementary external fields to create artificial atoms meeting the stringent requirements posed by scalable semiconductor-based quantum technology.

A qualitative analysis of an advanced practice nurse-directed transitional care model intervention

PURPOSE

The purpose of this study was to describe barriers and facilitators to implementing a transitional care intervention for cognitively impaired older adults and their caregivers lead by advanced practice nurses (APNs).

DESIGN AND METHODS

APNs implemented an evidence-based protocol to optimize transitions from hospital to home. An exploratory, qualitative directed content analysis examined 15 narrative case summaries written by APNs and fieldnotes from biweekly case conferences.

RESULTS

Three central themes emerged: patients and caregivers having the necessary information and knowledge, care coordination, and the caregiver experience. An additional category was also identified, APNs going above and beyond.

IMPLICATIONS

APNs implemented individualized approaches and provided care that exceeds the type of care typically staffed and reimbursed in the American health care system by applying a Transitional Care Model, advanced clinical judgment, and doing whatever was necessary to prevent negative outcomes. Reimbursement reform as well as more formalized support systems and resources are necessary for APNs to consistently provide such care to patients and their caregivers during this vulnerable time of transition.

Nanomembrane quantum-light-emitting diodes integrated onto piezoelectric actuators

We integrate resonant-cavity light-emitting diodes containing quantum dots onto substrates with giant piezoelectric response. Via strain, the energy of the photons emitted by the diode can be precisely controlled during electrical injection over a spectral range larger than 20 meV. Simultaneously, the exciton fine-structure-splitting and the biexciton binding energy can be tuned to the values required for entangled photon generation.

Electron mass in dilute nitrides and its anomalous dependence on hydrostatic pressure

The dependence of the electron mass on hydrostatic pressure P in N-diluted GaAs1-xNx (x=0.10% and 0.21%) is investigated by magnetophotoluminescence. Exceedingly large fluctuations (up to 60%/kbar) in the electron mass with increasing P are found. These originate from a pressure-driven tuning of the hybridization degree between the conduction band minimum and specific nitrogen-related states. Present results suggest a hierarchy between different nitrogen complexes as regards the extent of the perturbation these complexes exert on the electronic properties of the GaAs host.

Increased intima-media thickness of the carotid artery wall, normal blood pressure profile and normal left ventricular mass in subjects with primary hyperparathyroidism

OBJECTIVE

Despite the increasing evidence that primary hyperparathyroidism (PHPT) contributes to greater risk of cardiovascular morbidity and mortality, its exact role in the development of cardiovascular changes and its clinical significance are still controversial. Given the multiple influence of PHPT on the cardiovascular system, this study aimed to assess the effects of PHPT on blood pressure profile, and on features of the heart and arterial vessels in normotensive symptomless patients.

DESIGN

Twenty patients (8 males and 12 females) with a median age of 51.5 years (range 44 to 65 years) were evaluated and the results were compared with those of 20 controls matched for age, gender and body mass index. Patients' parathyroid hormone levels ranged from 172 to 454 pg/ml and Ca levels ranged from 11.4 to 13.5 mg/dl. Fasting levels of glucose, insulin, total and high density lipoprotein cholesterol and triglycerides were within the normal range in all subjects recruited.

METHODS

Twenty-four-hour blood pressure profile, left ventricle (LV) dimension and carotid artery anatomy were investigated, the latter two by ultrasonography.

RESULTS

No difference was found between the patients and controls in blood pressure profile, when the following parameters were considered: supine systolic/diastolic pressure, average 24-h systolic, diastolic and mean arterial pressure, day-time mean arterial pressure and fall in nocturnal blood pressure (-17% and -18% respectively). Heart rate and all parameters of LV mass were similar in patients and controls. The only alteration found in patients was in significantly greater carotid intimal-medial thickness (IMT) (P<0.001). Atherosclerotic plaques were more frequent in patients than in controls, with a difference reaching a trend (40% vs 10%, chi(2)=4.8; P=0.091). Considering that the carotid IMT is considered to be a marker of systemic atherosclerosis, our finding suggests early atherosclerotic changes in PHPT. No correlation was found between the severity and cardiovascular manifestation of PHPT.

CONCLUSIONS

Vascular changes may occur due to a combination of structural and functional impairments in PHPT patients, likely as a result of altered calcium metabolism and impaired equilibrium of other factors regulating vascular function. Both extent and duration of PHPT can play a relative role in the development of cardiovascular complications. Considering that PHPT is now recognized as a quite common and often symptomless endocrine disorder, the evidence of cardiovascular manifestation in normotensive patients, found by this morphological study, suggests a possible implication for the management of such patients. In this light, screening for abnormalities in cardiovascular system function should be recommended in all PHPT subjects.

Cosmic microwave background anisotropies with mixed isocurvature perturbations

In the light of the recent high quality data of the cosmic microwave background anisotropies, several estimations of cosmological parameters have been published. We study to what extent these estimations depend on assumptions about the initial conditions of the cosmological perturbations, which are usually supposed to be adiabatic. We show that, for more generic initial conditions, not only the best fit values are very different but the allowed parameter range enlarges dramatically. This raises the question which cosmological information (matter content of the Universe vs physics of inflation) can be reliably extracted from these data.

B-Myb overexpression results in activation and increased Fas/Fas ligand-mediated cytotoxicity of T and NK cells

The human B-myb gene encodes a transcriptional regulator that plays an important role in cell cycle progression, differentiation, and survival. To assess the in vivo role of B-myb, we investigated the phenotype of mouse transgenic lines in which B-Myb expression in lymphoid tissues was driven by the LCK proximal promoter. Overexpression of B-Myb had no measurable effect on the subsets of splenic and thymic lymphocytes, but was associated with increased expression of Fas ligand in NK and T cells. B-Myb-overexpressing splenocytes expressed higher IFN-gamma levels and contained higher percentages of cytokine-producing cells than wild-type (wt) splenocytes, as detected by Western blot analysis and ELISPOT assays, respectively. Ex vivo-cultured transgenic thymocytes and splenocytes had decreased survival compared with the corresponding cells from wt mice, possibly dependent on increased expression of Fas ligand. In addition, Fas ligand-dependent cytotoxicity of transgenic T and NK cells was significantly higher than that mediated by their wt counterparts. Together, these results indicate that B-Myb overexpression results in T and NK cell activation and increased cytotoxicity. Therefore, in addition to its well-established role in proliferation and differentiation, B-myb also appears to be involved in activation of NK and T cells and in their regulation of Fas/Fas ligand-mediated cytotoxicity

[Evaluation of oocyte maturity in patients undergoing ICSI and R-FSH treatment]

BACKGROUND

This study compares embryo quality, fertilisation rate and pregnancy rates after ICSI related with the quality of oocytes achieved after r-FSH stimulation.

METHODS

We evaluated 955 oocytes from patients following r-FSH and 643 oocytes from patients stimulated with ultrapure urinary FSH. The oocytes were divided into: a) normal oocytes; b) ooctyes with extra cytoplasmatic abnormalities (dark zona pellucida, wide perivitelline space); c) oocytes with cytoplasmatic abnormalities (dark cytoplasm, granular cytoplasm, retractile body), d) oocytes with shape abnormalities; e) oocytes with double abnormalities; f) oocytes with triple abnormalities. The embryos were divided into: A) even and homogeneous blastomeres without fragmentation; B) even and homogeneous blastomeres with <20% fragmentation; C) uneven and non-homogeneous blastomeres with 20-50% fragmentation; D) uneven and non homogeneous blastomere with >50% fragmentation.

RESULTS

40.9% of oocytes from patients treated with r-FSH have a normal morphology vs 35.2% of control groups (p<0.04). Abnormalities have a similar frequency in the two groups, except for the presence of three combined abnormalities (7.7 vs 5.4%; p<0.04). Fertilisation rate, cleavage rate, oocyte quality and pregnancy rate do not appear to be influenced by oocyte morphology and the type of FSH used for stimulation.

CONCLUSIONS

The administration of r-FSH allows a large number of oocytes to be rescued, with a high incidence of normal morphology. The fertilisation rate and the quality of embryos obtained from oocytes with structural abnormalities are similar to those observed in morphologically normal oocytes. Even the probability of pregnancy is similar in the two groups.

Bcl-2 expression restores the leukemogenic potential of a BCR/ABL mutant defective in transformation

Growth factor-dependent hematopoietic cell lines expressing the BCR/ABL oncoprotein of the Ph chromosome show growth factor-independent proliferation and resistance to apoptosis. Apoptosis resistance of BCR/ABL-expressing cells may depend on enhanced expression of anti-apoptotic proteins as well as reduced expression and/or inactivation of pro-apoptotic proteins. Compared to myeloid precursor 32Dcl3 cells expressing wild type BCR/ABL, cells expressing a BCR/ABL mutant lacking amino acids 176-426 in the BCR domain (p185 delta BCR) are susceptible to apoptosis induced by interleukin-3 (IL-3) deprivation. These cells exhibited the hypophosphorylated apoptotic BAD and markedly reduced levels of Bcl-2. Upon ectopic expression of Bcl-2, these cells showed no changes in BAD phosphorylation, but they became apoptosis-resistant and proliferated in the absence of IL-3, albeit more slowly than cells expressing wild type BCR/ABL. Moreover, the p185 delta BCR/Bcl-2 double transfectants were leukemogenic when injected into immunodeficient mice, but Bcl-2 expression did not restore the leukemia-inducing effects of p185 delta BCR to the levels of wild type BCR/ABL. Leukemic cells recovered from the spleen of mice injected with p185 delta BCR/Bcl-2 cells did not show rearrangements in the Bcl-2 genomic locus, but they exhibited enhanced proliferation in culture and induced a rapidly fatal disease process when inoculated in secondary recipient mice. Together, these data support the importance of anti-apoptotic pathways for BCR/ABL-dependent leukemogenesis and suggest that Bcl-2 expression promotes secondary changes leading to a more aggressive tumor phenotype. (Blood. 2000;96:3915-3921)

Differential role of p38 and c-Jun N-terminal kinase 1 mitogen-activated protein kinases in NK cell cytotoxicity

The serine-threonine mitogen-activated protein kinase (MAPK) family includes extracellular signal-regulated kinases (ERK), c-Jun N-terminal kinases (JNK), and p38 kinases. In NK cells, spontaneous or Ab-mediated recognition of target cells leads to activation of an ERK-2 MAPK-dependent biochemical pathway(s) involved in the regulation of NK cell effector functions. Here we assessed the roles of p38 and JNK MAPK in NK cell-mediated cytotoxicity. Our data indicate that p38 is activated in primary human NK cells upon stimulation with immune complexes and interaction with NK-sensitive target cells. FcgammaRIIIA-induced granule exocytosis and both spontaneous and Ab-dependent cytotoxicity were reduced in a dose-dependent manner in cells pretreated with either of two specific inhibitors of this kinase. Target cell-induced IFN-gamma and FcgammaRIIIA-induced TNF-alpha mRNA accumulation was similarly affected under the same conditions. Lack of inhibition of NK cell cytotoxicity in cells overexpressing an inactive form of JNK1 indicates that this kinase, activated only upon FcgammaRIIIA ligation, does not play a significant role in cytotoxicity. These data underscore the involvement of p38, but not JNK1, in the molecular mechanisms regulating NK cell cytotoxicity.

Activation of mitochondrial Raf-1 is involved in the antiapoptotic effects of Akt

The Akt serine/threonine kinase is required for the survival of many cell types and for transformation of hematopoietic cells by the BCR/ABL oncogenic tyrosine kinase. Analysis of the potential mechanisms whereby Akt promotes survival of hematopoietic cells revealed that it induced the activity of plasma membrane and mitochondrial Raf-1 in a Ras-independent, but PKC-dependent manner. Inhibition of plasma membrane Raf-1-dependent mitogen-activated protein kinase activity had no effect on the enhanced survival of cells expressing Akt. By contrast, suppression of mitochondrial Raf-1 enzymatic activity by expression of a mitochondria-targeted Raf-1 dominant-negative mutant rendered Akt-expressing cells susceptible to apoptosis induced by growth factor deprivation and was accompanied by inhibition of BAD, but not mitogen-activated protein kinase, phosphorylation. Together, these data indicate that PKC-dependent activation of Raf-1 plays an important role in Akt-dependent antiapoptotic effects.

Dependence of both spontaneous and antibody-dependent, granule exocytosis-mediated NK cell cytotoxicity on extracellular signal-regulated kinases

Extracellular signal-regulated kinases (ERK, also known as mitogen-activated protein kinases) are serine-threonine kinases transducing signals elicited upon ligand binding to several tyrosine kinase-associated receptors. We have reported that ERK2 phosphorylation and activation follows engagement of the low affinity receptor for the Fc portion of IgG (CD16) on NK cells, and is necessary for CD16-induced TNF-alpha mRNA expression. Here, we analyzed the involvement of ERK in NK cell-mediated cytotoxicity and IFN-gamma expression induced upon stimulation with targets cells, coated or not with Abs. Our data indicate that, as with immune complexes, ERK2 phosphorylation occurs in human primary NK cells upon interaction with target cells sensitive to granule exocytosis-mediated spontaneous cytotoxicity, and that this regulates both target cell- and immune complex-induced cytotoxicity and IFN-gamma mRNA expression. A specific inhibitor of mitogen-activated protein kinase kinase reduced both spontaneous and Ab-dependent cytotoxicity in a dose-dependent manner involving, at least in part, inhibition of granule exocytosis without affecting effector/target cell interaction and rearrangement of the cytoskeleton proteins actin and tubulin. Involvement of ERK in the regulation of Ca2+-dependent cell-mediated cytotoxicity was confirmed, using a genetic approach, in primary NK cells infected with a recombinant vaccinia virus encoding an ERK inactive mutant. These data indicate that the biochemical pathways elicited in NK cells upon engagement of receptors responsible for either spontaneous or Ab-dependent recognition of target cells, although distinct, utilize ERK as one of their downstream molecules to regulate effector functions.

TLS/FUS, a pro-oncogene involved in multiple chromosomal translocations, is a novel regulator of BCR/ABL-mediated leukemogenesis

The leukemogenic potential of BCR/ABL oncoproteins depends on their tyrosine kinase activity and involves the activation of several downstream effectors, some of which are essential for cell transformation. Using electrophoretic mobility shift assays and Southwestern blot analyses with a double-stranded oligonucleotide containing a zinc finger consensus sequence, we identified a 68 kDa DNA-binding protein specifically induced by BCR/ABL. The peptide sequence of the affinity-purified protein was identical to that of the RNA-binding protein FUS (also called TLS). Binding activity of FUS required a functional BCR/ABL tyrosine kinase necessary to induce PKCbetaII-dependent FUS phosphorylation. Moreover, suppression of PKCbetaII activity in BCR/ABL-expressing cells by treatment with the PKCbetaII inhibitor CGP53353, or by expression of a dominant-negative PKCbetaII, markedly impaired the ability of FUS to bind DNA. Suppression of FUS expression in myeloid precursor 32Dcl3 cells transfected with a FUS antisense construct was associated with upregulation of the granulocyte-colony stimulating factor receptor (G-CSFR) and downregulation of interleukin-3 receptor (IL-3R) beta-chain expression, and accelerated G-CSF-stimulated differentiation. Downregulation of FUS expression in BCR/ABL-expressing 32Dcl3 cells was associated with suppression of growth factor-independent colony formation, restoration of G-CSF-induced granulocytic differentiation and reduced tumorigenic potential in vivo. Together, these results suggest that FUS might function as a regulator of BCR/ABL leukemogenesis, promoting growth factor independence and preventing differentiation via modulation of cytokine receptor expression.

T wave alternans associated with HIV cardiomyopathy, erythromycin therapy, and electrolyte disturbances

We report a case of T wave alternans in a patient with HIV cardiomyopathy. T wave alternans is an unusual electrocardiographic finding in acquired long QT syndromes that can precede the development of torsades de pointes. Our patient had multiple risk factors for the development of the acquired long QT syndrome, including HIV cardiomyopathy, electrolyte disturbances, and erythromycin therapy. T wave alternans has not been described previously with HIV cardiomyopathy and only rarely with erythromycin therapy. Patients who have HIV cardiomyopathy and who receive intravenous erythromycin may benefit from monitoring for QT prolongation and electrolyte disturbances to avoid the development of torsades de pointes.

The SH3 domain contributes to BCR/ABL-dependent leukemogenesis in vivo: role in adhesion, invasion, and homing

To determine the possible role of the BCR/ABL oncoprotein SH3 domain in BCR/ABL-dependent leukemogenesis, we studied the biologic properties of a BCR/ABL SH3 deletion mutant (delta SH3 BCR/ABL) constitutively expressed in murine hematopoietic cells. delta SH3 BCR/ABL was able to activate known BCR/ABL-dependent downstream effector molecules such as RAS, PI-3kinase, MAPK, JNK, MYC, JUN, STATs, and BCL-2. Moreover, expression of delta SH3 BCR/ABL protected 32Dcl3 murine myeloid precursor cells from apoptosis, induced their growth factor-independent proliferation, and resulted in transformation of primary bone marrow cells in vitro. Unexpectedly, leukemic growth from cells expressing delta SH3 BCR/ABL was significantly retarded in SCID mice compared with that of cells expressing the wild-type protein. In vitro and in vivo studies to determine the adhesive and invasive properties of delta SH3 BCR/ABL-expressing cells showed their decreased interaction to collagen IV- and laminin-coated plates and their reduced capacity to invade the stroma and to seed the bone marrow and spleen. The decreased interaction with collagen type IV and laminin was consistent with a reduced expression of alpha 2 integrin by delta SH3 BCR/ABL-transfected 32Dcl3 cells. Moreover, as compared with wild-type BCR/ABL, which localizes primarily in the cytoskeletal/membrane fraction, delta SH3 BCR/ABL was more evenly distributed between the cytoskeleton/membrane and the cytosol compartments. Together, the data indicate that the SH3 domain of BCR/ABL is dispensable for in vitro transformation of hematopoietic cells but is essential for full leukemogenic potential in vivo.

Transformation of hematopoietic cells by BCR/ABL requires activation of a PI-3k/Akt-dependent pathway

The BCR/ABL oncogenic tyrosine kinase activates phosphatidylinositol 3-kinase (PI-3k) by a mechanism that requires binding of BCR/ABL to p85, the regulatory subunit of PI-3k, and an intact BCR/ABL SH2 domain. SH2 domain BCR/ABL mutants deficient in PI-3k activation failed to stimulate Akt kinase, a recently identified PI-3k downstream effector with oncogenic potential, but did activate p21 RAS and p70 S6 kinase. The PI-3k/Akt pathway is essential for BCR/ABL leukemogenesis as indicated by experiments demonstrating that wortmannin, a PI-3k specific inhibitor at low concentrations, suppressed BCR/ABL-dependent colony formation of murine marrow cells, and that a kinase-deficient Akt mutant with dominant-negative activity inhibited BCR/ABL-dependent transformation of murine bone marrow cells in vitro and suppressed leukemia development in SCID mice. In complementation assays using mouse marrow progenitor cells, the ability of transformation-defective SH2 domain BCR/ABL mutants to induce growth factor-independent colony formation and leukemia in SCID mice was markedly enhanced by expression of constitutively active Akt. In retrovirally infected mouse marrow cells, the BCR/ABL mutant lacking the SH2 domain was unable to upregulate the expression of c-Myc and Bcl-2; in contrast, expression of a constitutively active Akt mutant induced Bcl-2 and c-Myc expression, and stimulated the transcription activation function of c-Myc. Together, these data demonstrate the requirement for the BCR/ABL SH2 domain in PI-3k activation and document the essential role of the PI-3k/Akt pathway in BCR/ABL leukemogenesis.

Fas-induced changes in cdc2 and cdk2 kinase activity are not sufficient for triggering apoptosis in HUT-78 cells

Recent evidence suggested a role for the cell cycle dependent kinases cdc2 and cdk2 in apoptosis. An important mechanism by which many cell types could undergo apoptosis is through the activation of the Fas molecule on the cell membrane. To investigate whether Fas-induced cell death activated cdc2 and cdk2 kinases inappropriately, the human T lymphoma cells HUT-78, which express a high copy number of Fas, and two other previously characterized subclones of the same cell line which express mutant, cell death-deficient dominant-negative forms of Fas, were Fas-challenged and the changes in cdc2 and cdk2 kinase activity monitored. In both wild-type and Fas-mutated HUT-78 cells, apoptosis was associated simultaneously with decreased cdc2 and increased cdk2 activity. This association suggested that changes in cdc2 and cdk2 kinase activity are secondary events in cell death mediated by Fas.

A cell proliferation-dependent multiprotein complex NC-3A positively regulates the CD34 promoter via a TCATTT-containing element

The CD34 cell surface antigen is a glycoprotein expressed by hematopoietic stem and progenitor cells and also by certain nonhematopoietic cell-types. Because CD34 expression is regulated both at the transcriptional and the posttranscriptional level, we attempted to identify factors that, by interacting with the 5' flanking region of the human CD34 gene, may regulate its promoter activity in proliferating hematopoietic cells. By electrophoretic mobility shift assay, UV cross-linking and DNase I footprinting analyses, we identified a multiprotein complex, designated NC-3A, that specifically interacts with the CD34 promoter region from nucleotides -375 to -351. Sequence analysis of this region revealed the presence of a distinct motif, TCATTT. Chloramphenicol acetyl-transferase assays used to assess promoter activity in transiently transfected cells showed that this TCATTT-containing element, which is conserved in both the human and the murine CD34 genes, mediates positive regulatory activity in hematopoietic and nonhematopoietic cells, and acts as an enhancer when placed upstream of a heterologous promoter. Moreover, loss of CD34 promoter activity was caused by mutation of the TCATTT motif. In addition, the interaction of the nuclear multiprotein complex NC-3A with this enhancer element is proliferation-dependent. These data indicate that, although not cell-type specific, the formation of a multiprotein complex NC-3A interacting with the region from nucleotides -375 to 351 plays an important role in controlling CD34 promoter activity in proliferating hematopoietic cells.

Fc gamma R-dependent mitogen-activated protein kinase activation in leukocytes: a common signal transduction event necessary for expression of TNF-alpha and early activation genes

Cross-linking the receptors for the Fc domain of IgG (Fc gamma R) on leukocytes induces activation of protein tyrosine kinases. The intermediary molecules that transduce to the nucleus the signals leading to induction of the diverse biological responses mediated by these receptors are not clearly identified. We have investigated whether mitogen-activated protein kinases (MAPK) are involved in transmembrane signaling via the three Fc gamma R present on monocytic, polymorphonuclear, and natural killer (NK) cells. Our results indicate that occupancy of Fc gamma RI and Fc gamma RII on the monocytic cell line THP-I and on polymorphonuclear leukocytes (PMN) induces, transiently and with fast kinetics, MAPK phosphorylation, as indicated by decreased electrophoretic mobility in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and increased amounts of the proteins in antiphosphotyrosine antibody immunoprecipitates. This, associated with increased enzymatic activity, also occurs upon stimulation of the transmembrane isoform of CD16 (Fc gamma RIIIA) in NK cells and in a T cell line expressing transfected Fc gamma RIIIA alpha ligand-binding chain in association with zeta, but not upon stimulation of the glycosil-phosphatidylinositol-anchored Fc gamma RIIIB on PMN. Using the specific MAP kinase kinase inhibitor-PD 098059, we show that activation of MAPK is necessary for the Fc gamma R-dependent induction of c-fos and tumor necrosis factor alpha mRNA expression in monocytes and NK cells. These results underscore the role of MAPK as signal-transducing molecules controlling the expression of different genes relevant to leukocyte biology upon Fc gamma R stimulation.

Triggering of human monocyte activation through CD69, a member of the natural killer cell gene complex family of signal transducing receptors

The expression and function of CD69, a member of the natural killer cell gene complex family of signal transducing receptors, was investigated on human monocytes. CD69 was found expressed on all peripheral blood monocytes, as a 28- and 32-kD disulfide-linked dimer. Molecular cross-linking of CD69 receptors induced extracellular Ca2+ influx, as revealed by flow cytometry. CD69 cross-linking resulted also in phospholipase A2 activation, as detected by in vivo arachidonic acid release measurement from intact cells and by direct in vitro measurement of enzymatic activity using radiolabeled phosphatidylcholine vesicles. Prostaglandin E 2 alpha, 6-keto-prostaglandin F 1 alpha, and leukotriene B4 were detected by radioimmunoassay in supernatants from CD69-stimulated monocytes, suggesting the activation of both cyclooxygenase and lipoxygenase pathways after CD69 stimulation. CD69 cross-linking, moreover, was able to induce strong nitric oxide (NO) production from monocytes, as detected by accumulation of NO oxydixed derivatives, and cyclic GMP. It is important to note that NO generation was responsible for CD69-mediated increase in spontaneous cytotoxicity against L929 murine transformed fibroblast cell line and induction of redirected cytotoxicity towards P815 FcRII+ murine mastocytoma cell line. These data indicate that CD69 can act as a potent stimulatory molecule on the surface of human peripheral blood monocytes.

Transcriptional regulation of interleukin-2 gene expression by CD69-generated signals

The 5' flanking region of the human interleukin (IL)-2 gene was investigated for enhancer activity in response to CD69-generated signals, using a chloramphenicol acetyltransferase (CAT)-driven transient expression system in Jurkat cells. The region extending from -317 to +47 relative to the initiation site of IL-2 gene transcription was shown to contain sequences able to respond to CD69 cross-linking, by enhancing by about 100% a phorbol 12-myristate 13-acetate (PMA)-plus-ionomycin stimulation of CAT activity. A similar increase in CAT activity produced by PMA-plus-anti-CD3 mAb was induced by CD69 cross-linking, while a 200% increase over that obtained by PMA-plus-anti-CD28 mAb stimulation was seen. Analysis of enhancer deletion mutants revealed that proximal AP-1, OCT-1/octamer-associated protein and nuclear factor of activated T cells (NFAT) binding regions were all necessary to allow CD69-mediated enhancement of CAT activity. By gel mobility shift analysis, cyclosporin A-sensitive NFAT-binding induction and enhancement of AP-1 binding activity could be detected in nuclear extracts of both Jurkat and peripheral blood T cells after simultaneous CD69 and protein kinase C stimulation. Finally, CD69-mediated signals could increase NFAT and AP-1 binding activity following PMA and ionomycin stimulation in peripheral blood T cells. Collectively, these data suggest that CD69-generated signals participate in the control of the IL-2 gene expression at the transcriptional level, likely acting through NFAT and AP-1 transcription factor complexes.

Regulation of protein kinase C activity in neuronal differentiation induced by the N-ras oncogene in PC-12 cells

Expression of the N-ras oncogene under the control of the glucocorticoid-responsive promoter in the pheochromocytoma cell line UR61, a subline of PC-12 cells, has been used to investigate the differentiation process to neuronal cells triggered by ras oncogenes (I. Guerrero, A. Pellicer, and D. E. Burstein, Biochem. Biophys. Res. Commun. 150:1185-1192, 1988). Using ras-inducible cell lines, we observed that expression of the oncogenic N-ras p21 protein interferes with the ability of phorbol esters to induce downregulation of protein kinase C. This effect was associated with the appearance of immunologically detectable protein kinase C as well as the activity of the enzyme as analyzed either by binding of [3H]phorbol-12,13-dibutyrate in intact cells or by in vitro kinase activity. These results indicate a relationship between ras p21 and protein kinase C in neuronal differentiation in this model system. Comparison to the murine fibroblast system suggests that this relationship may be functional.