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SOLAR (NCT04542070; registered 2020-09-09) is a Phase 3b study that demonstrated the noninferior virological efficacy of switching to cabotegravir + rilpivirine long-acting (CAB + RPV LA) dosed every 2 months vs. continuing daily oral bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) over 12 months. Participants were randomised (2:1) to switch to CAB + RPV LA or to continue BIC/FTC/TAF. Patient-reported endpoints included treatment preference, treatment satisfaction (12-item HIV Treatment Satisfaction Questionnaire status version), acceptability of injections (Perception of Injection questionnaire [acceptability domain]) and three single-item questions exploring psychological challenges related to HIV treatment (fear of disclosure, adherence-related anxiety and reminder of HIV status). Of 670 participants, 447 participants switched to CAB + RPV LA and 223 continued BIC/FTC/TAF. Overall, 18% were female, median age was 37 years and 31% were non-White. At Month 12, CAB + RPV LA significantly improved treatment satisfaction vs. BIC/FTC/TAF (mean [95% confidence interval (CI)] change: + 3.36 [2.59, 4.13] vs. -1.59 [-2.71, -0.47]; p < 0.001). At Month 12, a higher proportion of CAB + RPV LA arm participants reported improvements across the psychological challenges related to HIV treatment questions compared with BIC/FTC/TAF participants. Participants indicating ≥ 1 psychological challenge at baseline experienced a statistically significant and clinically meaningful improvement in treatment satisfaction after 12 months of CAB + RPV LA vs. continuing BIC/FTC/TAF (adjusted difference [95% CI]: 7.96 [5.65, 10.26]; p < 0.001). Most (90%, 382/425) questionnaire respondents preferred CAB + RPV LA vs. BIC/FTC/TAF (5%, 21/425). Switching to CAB + RPV LA was associated with significantly improved treatment satisfaction and relief from the fear of disclosure, anxiety surrounding adherence and reminder of HIV status., (© 2024. The Author(s).)

Introduction: Cabotegravir plus rilpivirine (CAB + RPV) is the first complete long-acting (LA) regimen recommended for maintaining HIV-1 virological suppression. Cabotegravir And Rilpivirine Implementation Study in European Locations (CARISEL) is an implementation-effectiveness study examining the implementation of CAB+RPV LA administered every 2 months (Q2M) in European HIV centres. We present staff study participant (SSP) perspectives on the administration of CAB+RPV LA over 12 months., Methods: Eighteen clinics were randomized to one of two implementation support packages: standard arm (Arm-S) or enhanced arm (Arm-E). Arm-S included video injection training and provider/patient toolkits. Additionally, Arm-E included skilled wrap-around team meetings, face-to-face injection training and continuous quality improvement (CQI) calls. SSPs completed surveys on the acceptability, appropriateness and feasibility of CAB+RPV LA as an intervention and its implementation into their clinics, as well as barriers and facilitators to implementation. All surveys were completed at Month (M)1 (baseline), M5 and M12; data collection was completed by February 2022. Qualitative data were obtained from semi-structured interviews at M1, M5 and M12. The primary objective was assessed via formal statistical comparisons between study arms of the Acceptability of Implementation Measure, Implementation Appropriateness Measure and Feasibility of Implementation Measure surveys (1-5 Likert scale ranging from 1 = "completely disagree" to 5 = "completely agree"). Equivalent measures anchored to CAB+RPV LA as a therapy were also assessed., Results: Seventy SSPs completed surveys and interviews at M1, 68 at M5 and 62 at M12. Mean acceptability/appropriateness/feasibility scores were ≥3.8 (out of 5) at M12 for implementation- and intervention-based measures. An analysis of covariance showed no significant differences between study arms for these outcomes. Although barriers were noted, most SSPs were not overly concerned that these would impact implementation; concern about these anticipated barriers also decreased over time. At M12, 90.3% (n = 56/62) of SSPs held a positive opinion about CAB+RPV LA implementation. Qualitative interviews and CQI calls highlighted three top practices that supported implementation: implementation planning; education about CAB+RPV LA clinical efficacy; and education around administering injections and managing pain/discomfort after injections., Conclusions: CARISEL demonstrated that CAB+RPV LA dosed Q2M was successfully implemented across a range of European locations, with SSPs finding implementation highly acceptable, appropriate and feasible., Gov Number: NCT04399551., (© 2024 ViiV Healthcare and The Authors. Journal of the International AIDS Society published by John Wiley & Sons Ltd on behalf of International AIDS Society.)

Indistinguishable single photons in the telecom-bandwidth of optical fibers are indispensable for long-distance quantum communication. Solid-state single photon emitters have achieved excellent performance in key benchmarks, however, the demonstration of indistinguishability at room-temperature remains a major challenge. Here, we report room-temperature photon indistinguishability at telecom wavelengths from individual nanotube defects in a fiber-based microcavity operated in the regime of incoherent good cavity-coupling. The efficiency of the coupled system outperforms spectral or temporal filtering, and the photon indistinguishability is increased by more than two orders of magnitude compared to the free-space limit. Our results highlight a promising strategy to attain optimized non-classical light sources., (© 2024. The Author(s).)

We study experimentally and theoretically the hybridization among intralayer and interlayer moiré excitons in a MoSe&#95;{2}/WS&#95;{2} heterostructure with antiparallel alignment. Using a dual-gate device and cryogenic white light reflectance and narrow-band laser modulation spectroscopy, we subject the moiré excitons in the MoSe&#95;{2}/WS&#95;{2} heterostack to a perpendicular electric field, monitor the field-induced dispersion and hybridization of intralayer and interlayer moiré exciton states, and induce a crossover from type I to type II band alignment. Moreover, we employ perpendicular magnetic fields to map out the dependence of the corresponding exciton Landé g factors on the electric field. Finally, we develop an effective theoretical model combining resonant and nonresonant contributions to moiré potentials to explain the observed phenomenology, and highlight the relevance of interlayer coupling for structures with close energetic band alignment as in MoSe&#95;{2}/WS&#95;{2}.

Introduction: CARISEL is an implementation-effectiveness "hybrid" study examining the perspectives of people living with HIV-1 (patient study participants [PSPs]) on cabotegravir (CAB) plus rilpivirine (RPV) long-acting (LA) dosed every 2 months (Q2M) across 5 European countries., Methods: PSPs completed questionnaires on acceptability (Acceptability of Intervention Measure), appropriateness (Intervention Appropriateness Measure), and feasibility (Feasibility of Intervention Measure) at their first (Month [M] 1), third (M4), and seventh (M12) injection visits. Semistructured qualitative interviews were also conducted., Results: Overall, 437 PSPs were enrolled, of whom 430 received treatment. Median (interquartile range) age was 44 (37-51) years, 25.3% (n = 109/430) were female (sex at birth), and 21.9% (n = 94/430) were persons of color. Across time points, PSPs found CAB + RPV LA highly acceptable, appropriate, and feasible (mean scores ≥4.47/5). Qualitative data supported these observations., Conclusions: PSPs found CAB + RPV LA Q2M to be an acceptable, appropriate, and feasible treatment option., Competing Interests: Declaration of Conflicting InterestsThe authors declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: CAG, RM, RT, JS, MP-B, MA-K, BH, AdR, PM and MC are employees of ViiV Healthcare and may be stockholders of GSK. MvdV has received research grants and fees for participation in advisory boards from ViiV, MSD and Gilead. JP reports grants from Gilead and ViiV Healthcare and payments from lectures from Gilead and Janssen. EJ has received speaking fees or consulting activities from ViiV and Gilead laboratories and hospitality and congress registrations from ViiV, Gilead, MSD and Pfizer laboratories. LB and TL have no conflicts of interest to report. SBA, ELL, MH and NB are employees of Evidera who were paid by GSK/ViiV Healthcare to conduct the CARISEL study. NS is the director of London Safety and Training Solutions Ltd, which offers training and improvement and implementation solutions to healthcare organisations and the pharmaceutical industry.

Introduction: Cabotegravir and rilpivirine (CAB+RPV long-acting (LA)) is recommended as a treatment for HIV-1 allowing people living with HIV to receive 2 monthly injectable treatment, rather than daily pills. Providing injectable therapy in a system designed to provide and manage study participants on oral treatments poses logistical challenges namely how resources are used to accommodate patient preference within constrained health economies with capacity limitations. In this pragmatic multicentre study, we aim to understand the implementation of CAB-RPV-LA administration in two settings via mixed methods to explore perspectives of participants and the clinical team delivering CAB+RPV LA., Methods and Analysis: Women, racially minoritised people and older people are chronically under-represented in HIV clinical trials so the ILANA trial has set recruitment caps to ensure recruitment of 50% women, 50% ethnically diverse people and 30% over 50 years of age to include a more representative study population. Using a mixed-methods approach, the primary objective is to identify and evaluate the critical implementation strategies for CAB+RPV LA in both hospital and community settings. Secondary objectives include evaluating feasibility and acceptability of CAB+RPV LA administration at UK clinics and community settings from the perspective of HIV care providers, nurses and representatives at community sites, evaluating barriers to implementation, the utility of implementation strategies and adherence., Ethics and Dissemination: Ethical approval has been obtained from the Health Research Authority Research Ethics Committee (REC reference: 22/PR/0318). The dissemination strategy has been formulated with the SHARE Collaborative Community Advisory Board to maximise the impact of this work on clinical care and policy. This strategy draws on and leverages existing resources within the participating organisations, such as their academic infrastructure, professional relationships and community networks. The strategy will leverage the Public Engagement Team and press office to support dissemination of findings., Trial Registration Number: NCT05294159., Competing Interests: Competing interests: None of the authors have competing interests to declare in relation to this research. CMO has received research grants and honoraria from: ViiV Healthcare, GSK, GILEAD, MSD, Janssen & Astrazeneca. SU has none to declare. HF has received travel grants and honoraria from: Janssen-Cilag; travel grants from GILEAD, ViiV Healthcare, European Society of Clinical Virology, British HIV Association and the European AIDS Clinical Society., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Chirality is a fundamental asymmetry phenomenon, with chiral optical elements exhibiting asymmetric response in reflection or absorption of circularly polarized light. Recent realizations of such elements include nanoplasmonic systems with broken-mirror symmetry and polarization-contrasting optical absorption known as circular dichroism. An alternative route to circular dichroism is provided by spin-valley polarized excitons in atomically thin semiconductors. In the presence of magnetic fields, they exhibit an imbalanced coupling to circularly polarized photons and thus circular dichroism. Here, we demonstrate that polarization-contrasting optical transitions associated with excitons in monolayer WSe 2 can be transferred to proximal plasmonic nanodisks by coherent coupling. The coupled exciton-plasmon system exhibits magneto-induced circular dichroism in a spectrally narrow window of Fano interference, which we model in a master equation framework. Our work motivates the use of exciton-plasmon interfaces as building blocks of chiral metasurfaces for applications in information processing, nonlinear optics, and sensing.

In the cattle industry, in vivo or in vitro embryo production combined with genotyping and cryopreservation technologies allows the selection and conservation of embryos carrying genes for desirable traits. This study aimed to assess the efficiency of a vitrification method suitable for in-straw warming of biopsied in vivo derived (IVD) bovine embryos. Three experiments were carried out using two methodologies: the Cryotop®, the gold standard vitrification and 3-step warming methodology, or the VitTrans, a vitrification/in-straw 1-step warming method that enables direct embryo transfer to the uterus. In experiment 1, intact and biopsied in vitro produced (IVP) day 7 expanded blastocysts were vitrified using the Cryotop® and warmed in 1- or 3-steps. No differences in survival rates were recorded at 24 h after warming for intact or biopsied IVP blastocysts irrespective of the warming procedure. In experiment 2, the effect of the time from trophectoderm (TE) biopsy to vitrification/in-straw warming on post-warming survival rate was assessed. No significant differences in survival were observed when blastocysts were vitrified/in-straw warmed immediately after biopsy or after 3 h in culture when compared to intact blastocysts. In experiment 3, IVD embryos were vitrified 3 h after biopsy using the Cryotop® or the VitTrans method and pregnancy rates were assessed at day 60 after transfer. Fresh, biopsied embryos served as control. Similar pregnancy rates were observed when IVD biopsied embryos were transferred fresh or vitrified/warmed by the Cryotop® or VitTrans method. No significant effect of the embryo quality or developmental stage was detected on the percentage of pregnant recipients when IVD biopsied embryos were transferred fresh or after vitrification. While fresh female IVD embryos produced significantly higher pregnancy rates than male embryos, there were no differences in pregnancy rates when male or female vitrified/warmed embryos were transferred. About 81% from the biopsies analyzed successfully determined the embryo sex, confirming that DNA was there, and it was efficiently amplified. To conclude, our findings indicate that both vitrification methodologies produced similar post-warming outcomes for both intact and biopsied IVP embryos. Besides, vitrification/in-straw warming of biopsied IVD bovine embryos did not affect the viability to originate pregnancy, being a useful option for their direct transfer in field conditions., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Objectives: A novel long-acting regimen (LAR) of cabotegravir and rilpivirine for HIV treatment requires dosing every 2 months instead of daily. We assessed what proportion of people living with HIV and physicians would be interested in trying and offering LAR respectively and why., Methods: 688 people living with HIV on treatment, and 120 HIV physicians completed web-based surveys in Germany, Italy, the UK and France during 2019. Balanced description of a hypothetical LAR regarding efficacy, administration and possible side effects were provided. The hypothetical long-acting injections were assumed to be cost-neutral to current daily oral antiretrovirals. Interest of people living with HIV in trying ('very'/'highly') and physicians' willingness to offer ('definitely'/'probably') this LAR in different situations, with perceived benefits/concerns was measured., Results: Of people living with HIV, 65.8% were interested in trying LAR. The majority (~80%-90%) of those with unmet needs felt LAR would help, including those with strong medical needs (malabsorption and interfering gastrointestinal conditions), suboptimal adherence, confidentiality/privacy concerns and emotional burden of daily dosing. Of physicians, percentage willing to offer LAR varied situationally: strong medical need (dysphagia, 93.3%; malabsorption, 91.6%; interfering gastrointestinal issues, 90.0%; central nervous system disorders, 87.5%); suboptimal adherence (84.2%); confidentiality/privacy concerns (hiding medications, 86.6%) and convenience/lifestyle (84.2%). People living with HIV liked LAR for not having to carry pills when travelling (56.3%); physicians liked the increased patient contact (54.2%). Furthermore, 50.0% of people living with HIV perceived LAR would minimise transmission risk and improve their sexual health. The most disliked attribute was scheduling appointments (37.2%) and resource constraints (57.5%) for people living with HIV and physicians, respectively. Physicians estimated 25.7% of their patients would actually switch., Conclusion: Providers and people living with HIV viewed the described LAR as addressing several unmet needs. Alternative treatment routes and especially LAR may improve adherence and quality of life., Competing Interests: Competing interests: The following coauthors are employees of ViiV Healthcare or GSK: JS, MB, PR, FV, LR, GN, LF, VC and NVdeV., (© Author(s) (or their employer(s)) 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: The daily oral dosing requirement for antiretroviral therapy (ART) may be challenging for some people living with HIV (PLWHIV) with comorbid conditions, confidentiality concerns or pill fatigue. We investigated suboptimal adherence from the perspective of PLWHIV and HIV physicians., Methods: PLWHIV on ART (n = 688) and HIV physicians (n = 120) were surveyed during 2019 in France, Germany, Italy and the UK. Suboptimal adherence was a report the participant missed taking their dose as prescribed 'Sometimes'/'Often'/'Very often'. Physicians' interest in offering a hypothetical long-acting HIV regimen for suboptimally adherent patients was assessed. Descriptive and multivariable analyses were performed (P < 0.05)., Results: Of PLWHIV, 23.8% (164/688) reported suboptimal adherence vs. providers' estimated prevalence of 33.6% (SD = 28.8). PLWHIV-reported prevalence of specific suboptimal adherence behaviors were: mistimed dose [16.1% (111/688)]; missed a dose [15.7% (108/688)]; dosed under wrong conditions [e.g. food restrictions, 10.5% (72/688)] and overdosed [3.3% (23/688)]. Odds of suboptimal adherence were higher among those with vs. without a report of the following: dysphagia (AOR = 3.61, 95% CI = 2.28-5.74), stress/anxiety because of their daily dosing schedule (AOR = 3.09, 95% CI = 1.97-4.85), gastrointestinal side effects (AOR = 2.09, 95% CI = 1.39-3.15), neurocognitive/mental health conditions (AOR = 1.88, 95% CI = 1.30-2.72) or hiding their HIV medication (AOR = 1.51, 95% CI = 1.04-2.19). Of providers, 84.2% indicated they Definitely/Probably will offer a hypothetical long-acting HIV regimen 'for patients who have suboptimal levels of adherence to daily oral therapy (50-90%) for non-medical reasons'., Conclusions: Dysphagia, stressful daily oral dosing schedule, gastrointestinal side effects, neurocognitive/mental health conditions and confidentiality concerns were associated with suboptimal adherence in our study. Adherence support and alternative regimens, such as long-acting antiretroviral therapies, could help address these challenges., (© The Author(s) 2021. Published by Oxford University Press on behalf of the European Public Health Association.)

Layered two-dimensional materials exhibit rich transport and optical phenomena in twisted or lattice-incommensurate heterostructures with spatial variations of interlayer hybridization arising from moiré interference effects. Here, we report experimental and theoretical studies of excitons in twisted heterobilayers and heterotrilayers of transition metal dichalcogenides. Using MoSe 2 -WSe 2 stacks as representative realizations of twisted van der Waals bilayer and trilayer heterostructures, we observe contrasting optical signatures and interpret them in the theoretical framework of interlayer moiré excitons in different spin and valley configurations. We conclude that the photoluminescence of MoSe 2 -WSe 2 heterobilayer is consistent with joint contributions from radiatively decaying valley-direct interlayer excitons and phonon-assisted emission from momentum-indirect reservoirs that reside in spatially distinct regions of moiré supercells, whereas the heterotrilayer emission is entirely due to momentum-dark interlayer excitons of hybrid-layer valleys. Our results highlight the profound role of interlayer hybridization for transition metal dichalcogenide heterostacks and other realizations of multi-layered semiconductor van der Waals heterostructures.

The aim of the present study was to evaluate the effect of sperm selection by single-layer centrifugation (SLC) performed before freezing on sperm quality after thawing of Fleckvieh bull semen. Ejaculates from 22 bulls were collected by artificial vagina and divided into two aliquots. One aliquot (control sample) was diluted with Steridyl ® and frozen over nitrogen vapour in a Digitcool freezer (IMV Technologies). Sperm from the second aliquot (SLC sample) was selected using the SLC technique with Bovicoll colloid and then frozen over nitrogen vapour in a Digitcool freezer. After thawing, both samples (control and SLC) were evaluated by computer-aided sperm analysis (CASA; SCA 6.4 System; Microptic S.L) for sperm motility parameters. Integrity of the plasma membrane (viability), high mitochondrial membrane potential (HMMP) and acrosome integrity were assessed using a Guava® easyCyte flow cytometer (IMV Technologies). Morphological examination of spermatozoa was performed by Differential Interference Contrast microscopy (Leica DMi8). Morphological examination of live, immobilized spermatozoa was analysed under high magnification (≥6,600×). After thawing, the mean sperm viability of the control sample was 51.57%, compared to 40.37% for the SLC sample (p < .01). HMMP was higher (p < .01) in the control sample (40.37% versus 28.96%), and the mean of live spermatozoa with damaged acrosome was significantly higher (p < .03) in the SLC sample (1.63% versus 1.95%). The mean percentage of motile spermatozoa was 80.17% in the control sample, compared to 75.14% in the SLC sample (p < .0195), and rapid subpopulation reduced from 20.08% to 8.99% (p < .0001) after SLC. Percentage of hyperactivated sperm decreased from 12.23% to 4.28% (p < .0001) after SLC. Given the overall results, the sperm quality of thawed Fleckvieh bull semen was not improved when sperm were selected by SLC before freezing., (© 2020 Blackwell Verlag GmbH.)

The γ-amino butyric acid (GABA) type B receptors (GABA(B)R) function as chemoattractant receptors in response to GABA(B)R agonists in human neutrophils. The goal of this study was to define signaling mechanisms regulating GABA(B)R-mediated chemotaxis and cytoskeletal rearrangement. In a proteomic study we identified serine/threonine kinase Akt, tyrosine kinases Src and Pyk2, microtubule regulator kinesin and microtubule affinity-regulating kinase (MARK) co-immunoprecipitating with GABA(B)R. To define the contributions of these candidate signaling events in GABA(B)R-mediated chemotaxis, we used rat basophilic leukemic cells (RBL-2H3 cells) stably transfected with human GABA(B1b) and GABA(B2) receptors. The GABA(B)R agonist baclofen induced Akt phosphorylation and chemotaxis by binding to its specific GABA(B)R since pretreatment of cells with CGP52432, a GABA(B)R antagonist, blocked such effects. Moreover, baclofen induced Akt phosphorylation was shown to be dependent upon PI-3K and Src kinases. Baclofen failed to stimulate actin polymerization in suspended RBL cells unless exposed to a baclofen gradient. However, baclofen stimulated both actin and tubulin polymerization in adherent RBL-GABA(B)R cells. Blockade of actin and tubulin polymerization by treatment of cells with cytochalasin D or nocodazole respectively, abolished baclofen-mediated chemotaxis. Furthermore, baclofen stimulated Pyk2 and STAT3 phosphorylation, both known regulators of cell migration. In conclusion, GABA(B)R stimulation promotes chemotaxis in RBL cells which is dependent on signaling via PI3-K/Akt, Src kinases and on rearrangement of both microtubules and actin cytoskeleton. These data define mechanisms of GABA(B)R-mediated chemotaxis which may potentially be used to therapeutically regulate cellular response to injury and disease., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Mares can be artificially inseminated with chilled or frozen semen to increase the revenue from their offspring. Embryo transfer can be used to produce more than one foal from a single mare per season. Recent advances in using equine follicle-stimulating hormone to induce superovulation in mares have stimulated research on preserving equine embryos. Equine embryos are usually collected on day 7 or 8 after ovulation, and younger (day 6.5) embryos are typically cryopreserved. Cryopreservation improves the ability of veterinary clinicians to preserve embryos for implantation in recipient mares and facilitates international exchange of embryos.

In this three-year study, test scores for students taught veterinary obstetrics in a classroom setting with either traditional media (photographs, text, and two-dimensional graphical presentations) were compared with those for students taught by incorporating three-dimensional (3D) media (linear animations and interactive QuickTime Virtual Reality models) into the classroom lectures. Incorporation of the 3D animations and interactive models significantly increased students' scores on essay questions designed to assess their comprehension of the subject matter. This approach to education may help to better prepare students for dealing with obstetrical cases during their final clinical year and after graduation.

Reproductive performance in mares can be enhanced by various techniques. Protocols hastening the onset of follicular development help establish pregnancy in mares and ensure that foals are born early in the year. The time spent breeding mares can be reduced by synchronizing estrus and inducing ovulation. After successful fertilization of the oocyte, the developing embryo can survive in the uterus only if postbreeding endometritis, if present, is treated.

Activated neutrophils play an important role in the pathogenesis of sepsis, glomerulonephritis, acute renal failure, and other inflammatory processes. The resolution of neutrophil-induced inflammation relies, in large part, on removal of apoptotic neutrophils. Neutrophils are constitutively committed to apoptosis, but inflammatory mediators, such as GM-CSF, slow neutrophil apoptosis by incompletely understood mechanisms. We addressed the hypothesis that GM-CSF delays neutrophil apoptosis by activation of extracellular signal-regulated kinase (ERK) and phosphoinositide 3-kinase (PI 3-kinase) pathways. GM-CSF (20 ng/ml) significantly inhibited neutrophil apoptosis (GM-CSF, 32 vs 65% of cells p < 0. 0001). GM-CSF activated the PI 3-kinase/Akt pathway as determined by phosphorylation of Akt and BAD. GM-CSF-dependent Akt and BAD phosphorylation was blocked by the PI 3-kinase inhibitor LY294002. A role for the PI 3-kinase/Akt pathway in GM-CSF-stimulated delay of apoptosis was indicated by the ability of LY294002 to attenuate apoptosis delay. GM-CSF-dependent inhibition of apoptosis was significantly attenuated by PD98059, an ERK pathway inhibitor. LY294002 and PD98059 did not produce additive inhibition of apoptosis delay. To determine whether PI 3-kinase and ERK are used by other ligands that delay neutrophil apoptosis, we examined the role of these pathways in IL-8-induced apoptosis delay. LY294002 blocked IL-8-dependent Akt phosphorylation. PD98059 and LY294002 significantly attenuated IL-8 delay of apoptosis. These results indicate IL-8 and GM-CSF act, in part, to delay neutrophil apoptosis by stimulating PI 3-kinase and ERK-dependent pathways.

TNF-alpha enhances the response of polymorphonuclear leukocytes (PMN) to chemoattractants: however, the mechanism by which this occurs is unclear. We addressed the hypothesis that TNF-alpha enhances the PMN response to chemoattractants by increasing chemoattractant receptor transmembrane signaling, using fMLP as the model chemoattractant. fMLP-stimulated guanine nucleotide binding (G) protein activation was significantly increased in plasma membranes isolated from PMNs exposed to TNF-alpha 100 U/ml for 10 minutes (TNF-M), compared to membranes from control cells (CM). Formyl peptide receptor number and affinity were not significantly different in CM and TNF-M. Gi and Gs content were increased in TNF-M as measured by pertussis toxin and cholera toxin (CT) catalyzed ADP-ribosylation, respectively. The increased Gi was coupled to the formyl peptide receptor as shown by receptor-specific CT labeling of Gi. Immunoblot analysis showed that both G alpha i2 and G alpha 3 were increased in TNF-M. The functional activity of the increased G protein content was demonstrated by increased NaF-stimulated phospholipase D activity in TNF-alpha-treated PMNs. We conclude that TNF-alpha rapidly stimulates increased PMN plasma membrane expression of G proteins that couple formyl peptide receptors to effector enzymes. Regulation of G protein expression may be a significant mechanism by which TNF regulates PMN function.

The production of superoxide anion (O2-) by phagocytic cells plays an important role in host defenses and inflammatory processes. Interferon-gamma (IFN-gamma) primes neutrophils for increased O2- release stimulated by various agonists. This study examines if myeloid differentiated HL-60 cells also serve as a model for IFN-gamma-induced priming, and examines mechanism by which this priming occurs. IFN-gamma enhanced HL-60 cell superoxide production in response to F-Met-Leu-Phe (FMLP) in a concentration-dependent manner. Following a 4-h exposure, an increase in O2- production was seen with IFN-gamma at 0.1 U/ml, with optimal priming at 100 U/ml. The time course of priming by 100 U/ml IFN-gamma showed that at least a 1-h exposure was required, and a maximal effect was seen at 24 h. Priming after a 4-h exposure to 100 U/ml IFN-gamma was completely inhibited by 1 micrograms/ml cycloheximide. HL-60 cells cultivated with 100 U/ml IFN-gamma produced increased O2- when exposed to 25 mM NaF (containing AIF4) or 10 nM phorbol myristate acetate, agonists that trigger the respiratory burst independent of receptor stimulation. These results indicate that IFN-gamma primes the HL-60 cell respiratory burst in a concentration and time-dependent manner similar to its effect on neutrophils. The data are consistent with the hypothesis that IFN-gamma primes HL-60 cells, in part, by stimulating synthesis of proteins that participate in NADPH oxidase activation distal to the FMLP receptor.