[A global core outcome measurement set for snakebite clinical trials]. / Définition d'un jeu universel de critères de décision de base pour les essais cliniques sur les morsures de serpent.

Background: Snakebite clinical trials have often used heterogeneous outcome measures and there is an urgent need for standardisation. Method: A globally representative group of key stakeholders came together to reach consensus on a globally relevant set of core outcome measurements. Outcome domains and outcome measurement instruments were identified through searching the literature and a systematic review of snakebite clinical trials. Outcome domains were shortlisted by use of a questionnaire and consensus was reached among stakeholders and the patient group through facilitated discussions and voting. Results: Five universal core outcome measures should be included in all future snakebite clinical trials: mortality, WHO disability assessment scale, patient-specific functional scale, acute allergic reaction by Brown criteria, and serum sickness by formal criteria. Additional syndrome-specific core outcome measures should be used depending on the biting species. Conclusion: This core outcome measurement set provides global standardisation, supports the priorities of patients and clinicians, enables meta-analysis, and is appropriate for use in low-income and middle-income settings.

Faking Good on Self-Reports Versus Informant-Reports of Emotional Intelligence.

Research demonstrates that people can fake on self-rated emotional intelligence scales. As yet, no studies have investigated whether informants (where a knowledgeable informant rates a target's emotional intelligence) can also fake on emotional intelligence inventories. This study compares mean score differences for a simulated job selection versus a standard instructed set for both self-ratings and informant-ratings on the Trait Emotional Intelligence Questionnaire-Short Form (TEIQue-SF). In a 2 × 2 between-person design, participants (N = 81 community volunteers, 151 university students) completed the TEIQue-SF as either self-report or informant-report in one of two instruction conditions (answer honestly, job simulation). Both self-reports (d = 1.47) and informant-reports (d = 1.56) were significantly higher for job simulation than "answer honestly" instructions, indicating substantial faking. We conclude that people can fake emotional intelligence for both themselves (self-report) and on behalf of someone else (informant-report). We discuss the relevance of our findings for self- and informant-report assessment in applied contexts.

People with higher relationship satisfaction use more humor, valuing, and receptive listening to regulate their partners' emotions.

The emotional experiences you have with a romantic partner shape how satisfied you are in your relationship. Engaging in attempts to make a romantic partner feel better is linked with better relationship outcomes. However, it is not yet clear which specific processes people use to regulate their partners' emotions, nor which processes are most strongly linked with relationship satisfaction. In the current study of 277 individuals (55% female), we tested the extent to which eight extrinsic emotion regulation processes (expressive suppression, downward social comparison, humor, distraction, direct action, reappraisal, receptive listening, and valuing) predict relationship satisfaction. Six of the eight processes showed significant positive correlations with relationship satisfaction, with the strongest associations for valuing (r = .43), humor (r = .33), and receptive listening (r = .27). Relative weights were significant only for valuing, humor, and receptive listening, suggesting that these are the most important predictors of relationship satisfaction. Results are discussed in terms of the distinction between intrinsic and extrinsic regulation processes and the potential importance of motives for regulation. Supplementary Information: The online version contains supplementary material available at 10.1007/s12144-023-04432-4.

A global core outcome measurement set for snakebite clinical trials.

Snakebite clinical trials have often used heterogeneous outcome measures and there is an urgent need for standardisation. A globally representative group of key stakeholders came together to reach consensus on a globally relevant set of core outcome measurements. Outcome domains and outcome measurement instruments were identified through searching the literature and a systematic review of snakebite clinical trials. Outcome domains were shortlisted by use of a questionnaire and consensus was reached among stakeholders and the patient group through facilitated discussions and voting. Five universal core outcome measures should be included in all future snakebite clinical trials-mortality, WHO disability assessment scale, patient-specific functional scale, acute allergic reaction by Brown criteria, and serum sickness by formal criteria. Additional syndrome-specific core outcome measures should be used depending on the biting species. This core outcome measurement set provides global standardisation, supports the priorities of patients and clinicians, enables meta-analysis, and is appropriate for use in low-income and middle-income settings.

Neural Responses to Novel and Existing Words in Children with Autism Spectrum and Developmental Language Disorder.

The formation of new phonological representations is key in establishing items in the mental lexicon. Phonological forms become stable with repetition, time and sleep. Atypicality in the establishment of new word forms is characteristic of children with developmental language disorder (DLD) and autism spectrum disorder (ASD), yet neural changes in response to novel word forms over time have not yet been directly compared in these groups. This study measured habituation of event-related-potentials (ERPs) to novel and known words within and between two sessions spaced 24 hours apart in typically developing (TD) children, and their peers with DLD or ASD. We hypothesised that modulation of the auditory N400 amplitude would mark real-time changes in lexical processing with habituation evident within and across sessions in the TD group, while the DLD group would show attenuated habituation within sessions, and the ASD group attenuated habituation between sessions. Twenty-one typically developing children, 19 children with ASD, and 16 children with DLD listened passively to known and novel words on two consecutive days, while ERPs were recorded using dry electrodes. Counter to our hypotheses, no habituation effect emerged within sessions. However, responses did habituate between sessions, with this effect being reduced in the DLD group, indicating less pre-activation of lexical representations in response to words encountered the previous day. No differences in change over time were observed between the TD and ASD groups. These data are in keeping with theories stressing the importance of sleep-related consolidation in word learning.

Does the maturation of early sleep patterns predict language ability at school entry? A Born in Bradford study.

Children's vocabulary ability at school entry is highly variable and predictive of later language and literacy outcomes. Sleep is potentially useful in understanding and explaining that variability, with sleep patterns being predictive of global trajectories of language acquisition. Here, we looked to replicate and extend these findings. Data from 354 children (without English as an additional language) in the Born in Bradford study were analysed, describing the mean intercepts and linear trends in parent-reported day-time and night-time sleep duration over five time points between 6 and 36 months-of-age. The mean difference between night-time and day-time sleep was predictive of receptive vocabulary at age five, with more night-time sleep relative to day-time sleep predicting better language. An exploratory analysis suggested that socioeconomic status was predictive of vocabulary outcomes, with sleep patterns partially mediating this relationship. We suggest that the consolidation of sleep patterns acts as a driver of early language development.

Population-level faecal metagenomic profiling as a tool to predict antimicrobial resistance in Enterobacterales isolates causing invasive infections: An exploratory study across Cambodia, Kenya, and the UK.

BACKGROUND: Antimicrobial resistance (AMR) in Enterobacterales is a global health threat. Capacity for individual-level surveillance remains limited in many countries, whilst population-level surveillance approaches could inform empiric antibiotic treatment guidelines. METHODS: In this exploratory study, a novel approach to population-level prediction of AMR in Enterobacterales clinical isolates using metagenomic (Illumina) profiling of pooled DNA extracts from human faecal samples was developed and tested. Taxonomic and AMR gene profiles were used to derive taxonomy-adjusted population-level AMR metrics. Bayesian modelling, and model comparison based on cross-validation, were used to evaluate the capacity of each metric to predict the number of resistant Enterobacterales invasive infections at a population-level, using available bloodstream/cerebrospinal fluid infection data. FINDINGS: Population metagenomes comprised samples from 177, 157, and 156 individuals in Kenya, the UK, and Cambodia, respectively, collected between September 2014 and April 2016. Clinical data from independent populations included 910, 3356 and 197 bacterial isolates from blood/cerebrospinal fluid infections in Kenya, the UK and Cambodia, respectively (samples collected between January 2010 and May 2017). Enterobacterales were common colonisers and pathogens, and faecal taxonomic/AMR gene distributions and proportions of antimicrobial-resistant Enterobacterales infections differed by setting. A model including terms reflecting the metagenomic abundance of the commonest clinical Enterobacterales species, and of AMR genes known to either increase the minimum inhibitory concentration (MIC) or confer clinically-relevant resistance, had a higher predictive performance in determining population-level resistance in clinical Enterobacterales isolates compared to models considering only AMR gene information, only taxonomic information, or an intercept-only baseline model (difference in expected log predictive density compared to best model, estimated using leave-one-out cross-validation: intercept-only model = -223 [95% credible interval (CI): -330,-116]; model considering only AMR gene information = -186 [95% CI: -281,-91]; model considering only taxonomic information = -151 [95% CI: -232,-69]). INTERPRETATION: Whilst our findings are exploratory and require validation, intermittent metagenomics of pooled samples could represent an effective approach for AMR surveillance and to predict population-level AMR in clinical isolates, complementary to ongoing development of laboratory infrastructures processing individual samples.

Adult memory for specific instances of a repeated event: a preliminary review.

In cases of repeated victimisation, a complainant's statement of abuse, and therefore memory, is often critical evidence for forensic investigations and legal proceedings. It is therefore important to understand the functioning of adults' memory for repeated events. As such, the purpose of this paper was to review the extant literature on adult memory for instances of a repeated event. The results of the review revealed a small number of heterogeneous studies on adult repeated-event memory (N = 12). The literature so far shows that while adults might have difficulty in recalling information specific to instances (narrow accuracy), they are capable of remembering information across multiple instances (broad accuracy). It was also found that several factors may impact recall of instances including age, the number of experienced instances, rehearsing an event, repeated retrieval and event distinctiveness. The discussion highlights the forensic implications of this research and future research directions.

Small molecule inhibits T-cell acute lymphoblastic leukaemia oncogenic interaction through conformational modulation of LMO2.

Ectopic expression in T-cell precursors of LIM only protein 2 (LMO2), a key factor in hematopoietic development, has been linked to the onset of T-cell acute lymphoblastic leukaemia (T-ALL). In the T-ALL context, LMO2 drives oncogenic progression through binding to erythroid-specific transcription factor SCL/TAL1 and sequestration of E-protein transcription factors, normally required for T-cell differentiation. A key requirement for the formation of this oncogenic protein-protein interaction (PPI) is the conformational flexibility of LMO2. Here we identify a small molecule inhibitor of the SCL-LMO2 PPI, which hinders the interaction in vitro through direct binding to LMO2. Biophysical analysis demonstrates that this inhibitor acts through a mechanism of conformational modulation of LMO2. Importantly, this work has led to the identification of a small molecule inhibitor of the SCL-LMO2 PPI, which can provide a starting point for the development of new agents for the treatment of T-ALL. These results suggest that similar approaches, based on the modulation of protein conformation by small molecules, might be used for therapeutic targeting of other oncogenic PPIs.

A meta-analysis and systematic review of reactivity to judgements of learning.

Judgements of learning (JoL) are often used in memory research as a means for assessing an individual's metacognitive beliefs about their learning. JoL have been shown to reliably predict performance as well as learning behaviours and decisions . Participants may, however, modify their behaviour in response to performing JoL. There has, however, been little consensus as to the reliability and direction of the effect. We report on a meta-analyses that assesses the evidence that memory performance is reactive to JoL. The results indicate that overall providing JoL does not have a significant effect on memory performance (g = 0.054, 95% CI -0.027 to 0.135). However, sub-groups analysis showed that this effect depends on the nature of the stimuli to be recalled, with moderate positive reactivity observed for related word pairs (g = 0.323, 95% CI 0.083 to 0.563) and word lists (g = 0.384, 95% CI 0.146 to 0.622) but no reactivity when pairs were unrelated or a mixture of related and unrelated pairs. These results indicate that researchers should be aware that eliciting JoL may well influence participants' underlying encoding processes, especially when using related word pairs or word lists.

Neurocognitive Function at the First-Line Failure and on the Second-Line Antiretroviral Therapy in Africa: Analyses From the EARNEST Trial.

OBJECTIVE: To assess neurocognitive function at the first-line antiretroviral therapy failure and change on the second-line therapy. DESIGN: Randomized controlled trial was conducted in 5 sub-Saharan African countries. METHODS: Patients failing the first-line therapy according to WHO criteria after >12 months on non-nucleoside reverse transcriptase inhibitors-based regimens were randomized to the second-line therapy (open-label) with lopinavir/ritonavir (400 mg/100 mg twice daily) plus either 2-3 clinician-selected nucleoside reverse transcriptase inhibitors, raltegravir, or as monotherapy after 12-week induction with raltegravir. Neurocognitive function was tested at baseline, weeks 48 and 96 using color trails tests 1 and 2, and the Grooved Pegboard test. Test results were converted to an average of the 3 individual test z-scores. RESULTS: A total of 1036 patients (90% of those >18 years enrolled at 13 evaluable sites) had valid baseline tests (58% women, median: 38 years, viral load: 65,000 copies per milliliter, CD4 count: 73 cells per cubic millimeter). Mean (SD) baseline z-score was -2.96 (1.74); lower baseline z-scores were independently associated with older age, lower body weight, higher viral load, lower hemoglobin, less education, fewer weekly working hours, previous central nervous system disease, and taking fluconazole (P < 0.05 in multivariable model). Z-score was increased by mean (SE) of +1.23 (0.04) after 96 weeks on the second-line therapy (P < 0.001; n = 915 evaluable), with no evidence of difference between the treatment arms (P = 0.35). CONCLUSIONS: Patients in sub-Saharan Africa failing the first-line therapy had low neurocognitive function test scores, but performance improved on the second-line therapy. Regimens with more central nervous system-penetrating drugs did not enhance neurocognitive recovery indicating this need not be a primary consideration in choosing a second-line regimen.

Impact of second-line antiretroviral regimens on lipid profiles in an African setting: the DART trial sub-study.

BACKGROUND: Increasing numbers of HIV-infected patients in sub-Saharan Africa are exposed to antiretroviral therapy (ART), but there are few data on lipid changes on first-line ART, and even fewer on second-line. METHODS: DART was a randomized trial comparing monitoring strategies in Ugandan/Zimbabwean adults initiating first-line ART and switching to second-line at clinical/immunological failure. We evaluated fasting lipid profiles at second-line initiation and ≥48 weeks subsequently in stored samples from Zimbabwean patients switching before 18 September 2006. RESULTS: Of 91 patients switched to second-line ART, 65(73%) had fasting samples at switch and ≥48 weeks, 14(15%) died or were lost <48 weeks, 10(11%) interrupted ART for >14 days and 2(2%) had no samples available. 56/65(86%) received ZDV/d4T + 3TC + TDF first-line, 6(9%) ZDV/d4T + 3TC + NVP and 3(5%) ZDV + 3TC with TDF and NVP. Initial second-line regimens were LPV/r + NNRTI in 27(41%), LPV/r + NNRTI + ddI in 33(50%) and LPV/r + TDF + ddI/3TC/ZDV in 6(9%). At second-line initiation median (IQR) TC, LDL-C, HDL-C and TG (mmol/L) were 3.3(2.8-4.0), 1.7(1.3-2.2), 0.7(0.6-0.9) and 1.1(0.8-1.9) respectively. Levels were significantly increased 48 weeks later, by mean (SE) +2.0(0.1), +1.1(0.1), +0.5(0.05) and +0.4(0.2) respectively (p < 0.001; TG p = 0.01). 3% at switch vs 25% 48 weeks later had TC >5.2 mmol/L; 3% vs 25% LDL-C >3.4 mmol/L and 91% vs 41% HDL-C <1.1 mmol/L (p < 0.001). Similar proportions had TG >1.8 mmol/L (0 vs 3%) and TC/HDL-C ≥5 (40% vs 33%) (p > 0.15). CONCLUSION: Modest lipid elevations were observed in African patients on predominantly LPV/r + NNRTI-based second-line regimens. Routine lipid monitoring during second-line ART regimens may not be warranted in this setting but individual cardiovascular risk assessment should guide practice.

Anthropometric measurements and lipid profiles to detect early lipodystrophy in antiretroviral therapy experienced HIV-infected children in the CHAPAS-3 trial.

BACKGROUND: Few studies have investigated objective markers of lipodystrophy in African children. We compared body circumferences, skin-fold thickness (SFT) and lipids in antiretroviral therapy (ART)-naive and stavudine (d4T)-exposed children with HIV-uninfected controls. METHODS: In the CHAPAS-3 trial, HIV-infected children (ART-naive or on d4T for ≥2 years without clinical lipodystrophy) were randomized to d4T, abacavir or zidovudine with lamivudine (3TC) plus a non-nucleoside reverse transcriptase inhibitor. Mid-upper-arm circumference (MUAC) and calf circumference (CC), SFT (biceps, triceps, sub-scapular and supra-iliac) and fasting lipids (total cholesterol [TC], low-density lipoprotein [LDL], high-density lipoprotein [HDL] and triglycerides [TRIG]) were measured at randomization in all HIV-infected children, and in HIV-uninfected controls. Age- and sex-adjusted z-scores of MUAC, CC, SFT and the sum of SFT (SSF) using Dutch reference data were compared across groups using linear regression. RESULTS: Of 496 children, 49% were male, 299 (median age 2.5 years [IQR 1.5-4.0]) were ART-naive, 109 (median age 6 years [IQR 5.5-7.0]) were ART-experienced and 88 (median age 2.2 years [IQR 1.5-3.0]) were control children. Overall, 100% and 95% of ART-experienced children had been on d4T plus 3TC and nevirapine, respectively, for a median 3.5 years (IQR 2.6-4.2). Mean (sd) weight-for-age z-scores and MUAC z-scores were -1.51 (1.29) versus -0.90 (0.88) versus -0.33 (1.15) and -1.56 (1.25) versus -1.24 (0.97) versus -0.65 (1.06) in ART-naive versus -experienced versus controls, respectively (all P<0.02). The mean (sd) of SSF was lower in the ART-experienced (-0.78 [1.28]) than in the ART-naive (-0.32 [1.09]; P<0.0001) children and controls (-0.29 [0.88]; P<0.002). ART-experienced children had higher mean fasting TC, LDL and HDL but lower TRIG compared to ART-naive children (P-values <0.0001), and higher TC and HDL but lower TRIG compared to controls (P-values <0.01). CONCLUSIONS: In ART-experienced children on d4T-containing regimens, we observed lower SFT and higher TC and LDL values compared to ART-naive children and HIV-uninfected controls.

Clinical differences between younger and older adults with HIV/AIDS starting antiretroviral therapy in Uganda and Zimbabwe: a secondary analysis of the DART trial.

OBJECTIVE: Clinical and immunological data about HIV in older adults from low and middle income countries is scarce. We aimed to describe differences between younger and older adults with HIV starting antiretroviral therapy in two low-income African countries. SETTING: HIV clinics in Uganda and Zimbabwe. DESIGN: Secondary exploratory cross-sectional analysis of the DART randomized controlled trial. OUTCOME MEASURES: Clinical and laboratory characteristics were compared between adults aged 18-49 years (younger) and ≥ 50 years (older), using two exploratory multivariable logistic regression models, one with HIV viral load (measured in a subset pre-ART) and one without. RESULTS: A total of 3316 eligible participants enrolled in DART were available for analysis; 219 (7%) were ≥ 50 years and 1160 (35%) were male. Across the two adjusted regression models, older adults had significantly higher systolic blood pressure, lower creatinine clearance and were consistently less likely to be females compared to younger adults with HIV. Paradoxically, the models separately suggested that older adults had statistically significant (but not clinically important) higher CD4+ cell counts and higher plasma HIV-1 viral copies at initiation. Crude associations between older age and higher baseline hemoglobin, body mass index, diastolic blood pressure and lower WHO clinical stage were not sustained in the adjusted analysis. CONCLUSIONS: Our study found clinical and immunological differences between younger and older adults, in a cohort of Africans starting antiretroviral therapy. Further investigations should explore how these differences could be used to ensure equity in service delivery and affect outcomes of antiretroviral therapy.

The evolution of HIV-1 reverse transcriptase in route to acquisition of Q151M multi-drug resistance is complex and involves mutations in multiple domains.

BACKGROUND: The Q151M multi-drug resistance (MDR) pathway in HIV-1 reverse transcriptase (RT) confers reduced susceptibility to all nucleoside reverse transcriptase inhibitors (NRTIs) excluding tenofovir (TDF). This pathway emerges after long term failure of therapy, and is increasingly observed in the resource poor world, where antiretroviral therapy is rarely accompanied by intensive virological monitoring. In this study we examined the genotypic, phenotypic and fitness correlates associated with the development of Q151M MDR in the absence of viral load monitoring. RESULTS: Single-genome sequencing (SGS) of full-length RT was carried out on sequential samples from an HIV-infected individual enrolled in ART rollout. The emergence of Q151M MDR occurred in the order A62V, V75I, and finally Q151M on the same genome at 4, 17 and 37 months after initiation of therapy, respectively. This was accompanied by a parallel cumulative acquisition of mutations at 20 other codon positions; seven of which were located in the connection subdomain. We established that fourteen of these mutations are also observed in Q151M-containing sequences submitted to the Stanford University HIV database. Phenotypic drug susceptibility testing demonstrated that the Q151M-containing RT had reduced susceptibility to all NRTIs except for TDF. RT domain-swapping of patient and wild-type RTs showed that patient-derived connection subdomains were not associated with reduced NRTI susceptibility. However, the virus expressing patient-derived Q151M RT at 37 months demonstrated ~44% replicative capacity of that at 4 months. This was further reduced to ~22% when the Q151M-containing DNA pol domain was expressed with wild-type C-terminal domain, but was then fully compensated by coexpression of the coevolved connection subdomain. CONCLUSIONS: We demonstrate a complex interplay between drug susceptibility and replicative fitness in the acquisition Q151M MDR with serious implications for second-line regimen options. The acquisition of the Q151M pathway occurred sequentially over a long period of failing NRTI therapy, and was associated with mutations in multiple RT domains.

Clustering based on adherence data.

Adherence to a medical treatment means the extent to which a patient follows the instructions or recommendations by health professionals. There are direct and indirect ways to measure adherence which have been used for clinical management and research. Typically adherence measures are monitored over a long follow-up or treatment period, and some measurements may be missing due to death or other reasons. A natural question then is how to describe adherence behavior over the whole period in a simple way. In the literature, measurements over a period are usually combined just by using averages like percentages of compliant days or percentages of doses taken. In the paper we adapt an approach where patient adherence measures are seen as a stochastic process. Repeated measures are then analyzed as a Markov chain with finite number of states rather than as independent and identically distributed observations, and the transition probabilities between the states are assumed to fully describe the behavior of a patient. The patients can then be clustered or classified using their estimated transition probabilities. These natural clusters can be used to describe the adherence of the patients, to find predictors for adherence, and to predict the future events. The new approach is illustrated and shown to be useful with a simple analysis of a data set from the DART (Development of AntiRetroviral Therapy in Africa) trial in Uganda and Zimbabwe.

XLF-Cernunnos promotes DNA ligase IV-XRCC4 re-adenylation following ligation.

XLF-Cernunnos (XLF) is a component of the DNA ligase IV-XRCC4 (LX) complex, which functions during DNA non-homologous end joining (NHEJ). Here, we use biochemical and cellular approaches to probe the impact of XLF on LX activities. We show that XLF stimulates adenylation of LX complexes de-adenylated by pyrophosphate or following LX decharging during ligation. XLF enhances LX ligation activity in an ATP-independent and dependent manner. ATP-independent stimulation can be attributed to enhanced end-bridging. Whilst ATP alone fails to stimulate LX ligation activity, addition of XLF and ATP promotes ligation in a manner consistent with XLF-stimulated readenylation linked to ligation. We show that XLF is a weakly bound partner of the tightly associated LX complex and, unlike XRCC4, is dispensable for LX stability. 2BN cells, which have little, if any, residual XLF activity, show a 3-fold decreased ability to repair DNA double strand breaks covering a range of complexity. These findings strongly suggest that XLF is not essential for NHEJ but promotes LX adenylation and hence ligation. We propose a model in which XLF, by in situ recharging DNA ligase IV after the first ligation event, promotes double stranded ligation by a single LX complex.

ATR-dependent phosphorylation and activation of ATM in response to UV treatment or replication fork stalling.

The phosphatidyl inositol 3-kinase-like kinases (PIKKs), ataxia-telangiectasia mutated (ATM) and ATM- and Rad3-related (ATR) regulate parallel damage response signalling pathways. ATM is reported to be activated by DNA double-strand breaks (DSBs), whereas ATR is recruited to single-stranded regions of DNA. Although the two pathways were considered to function independently, recent studies have demonstrated that ATM functions upstream of ATR following exposure to ionising radiation (IR) in S/G2. Here, we show that ATM phosphorylation at Ser1981, a characterised autophosphorylation site, is ATR-dependent and ATM-independent following replication fork stalling or UV treatment. In contrast to IR-induced ATM-S1981 phosphorylation, UV-induced ATM-S1981 phosphorylation does not require the Nbs1 C-terminus or Mre11. ATR-dependent phosphorylation of ATM activates ATM phosphorylation of Chk2, which has an overlapping function with Chk1 in regulating G2/M checkpoint arrest. Our findings provide insight into the interplay between the PIKK damage response pathways.

DNA-PK autophosphorylation facilitates Artemis endonuclease activity.

The Artemis nuclease is defective in radiosensitive severe combined immunodeficiency patients and is required for the repair of a subset of ionising radiation induced DNA double-strand breaks (DSBs) in an ATM and DNA-PK dependent process. Here, we show that Artemis phosphorylation by ATM and DNA-PK in vitro is primarily attributable to S503, S516 and S645 and demonstrate ATM dependent phosphorylation at serine 645 in vivo. However, analysis of multisite phosphorylation mutants of Artemis demonstrates that Artemis phosphorylation is dispensable for endonuclease activity in vitro and for DSB repair and V(D)J recombination in vivo. Importantly, DNA-dependent protein kinase catalytic subunit (DNA-PKcs) autophosphorylation at the T2609-T2647 cluster, in the presence of Ku and target DNA, is required for Artemis-mediated endonuclease activity. Moreover, autophosphorylated DNA-PKcs stably associates with Ku-bound DNA with large single-stranded overhangs until overhang cleavage by Artemis. We propose that autophosphorylation triggers conformational changes in DNA-PK that enhance Artemis cleavage at single-strand to double-strand DNA junctions. These findings demonstrate that DNA-PK autophosphorylation regulates Artemis access to DNA ends, providing insight into the mechanism of Artemis mediated DNA end processing.

Highly active antiretroviral therapy interruption: predictors and virological and immunologic consequences.

OBJECTIVE: To characterize the magnitude and the predictors of highly active antiretroviral therapy (HAART) interruption (TI) and to investigate its immunologic and virological consequences. METHODS: Using Concerted Action on Seroconversion to AIDS and Death in Europe data from 8,300 persons with well-documented seroconversion dates, we identified subjects with stable first HAART (for at least 90 days) not initiated during primary infection. A TI was defined as an interruption of all antiretroviral therapy drugs for at least 14 days. RESULTS: Of 1,551 subjects starting HAART, 299 (19.3%) interrupted treatment. Median (interquartile range) duration of the TI was 189 (101-382) days. The cumulative probability (95% confidence interval) of TI at 2 years was 15.9% (14.0%-18.1%). Women were more likely to have a TI than men in the same exposure group (35.8% vs 24.2% among drug users, 22.1% vs 13.3% among heterosexuals; P < 0.05). Higher baseline viremia and poor immunologic response to HAART were associated with higher probabilities of TI. Median (interquartile range) individual CD4 cell loss during TI was 94 (1-220) cells/microL. Older age at HAART (>40 yr), lower pre-HAART nadir (<200 cells/microL), and lower CD4 at start of TI (<350 cells/microL) were significantly associated with greater relative CD4 loss during TI. CONCLUSIONS: We estimate that almost 1 in 6 subjects on HAART interrupts treatment by 2 years. Further research is needed to investigate the reasons why TI is higher in women. We have identified characteristics of subjects with the greatest risk for CD4 loss in whom TI may have greater risks.