Atrial fibrillation symptom reduction and improved quality of life following the hybrid convergent procedure: a CONVERGE trial subanalysis.

Background: CONVERGE was a prospective, multicenter, randomized controlled trial that evaluated the safety of Hybrid Atrial Fibrillation Convergent (HC) and compared its effectiveness to endocardial catheter ablation (CA) for the treatment of persistent atrial fibrillation (PersAF) and longstanding PersAF (LSPAF). In 2020, we reported that CONVERGE met its primary safety and effectiveness endpoints. The primary objective of the present study is to report CONVERGE trial results for quality of life (QOL) and Class I/III anti-arrhythmic drug (AAD) utilization following HC. Methods: Eligible patients had drug-refractory symptomatic PersAF or LSPAF and a left atrium diameter ≤6.0 cm. Enrolled patients were randomized 2:1 to receive HC or CA. Atrial Fibrillation Severity Scale (AFSS) and the 36-Item Short Form Health Survey (SF-36) were assessed at baseline and 12 months; statistical comparison was performed using paired t-tests. AAD utilization at baseline through 12 and 18 months post-procedure was evaluated; statistical comparison was performed using McNemar's tests. Results: A total of 153 patients were treated with either HC (n=102) or CA (n=51). Of the 102 HC patients, 38 had LSPAF. AFSS and SF-36 Mental and Physical Component scores were significantly improved at 12 months versus baseline with HC overall and for the subset of LSPAF patients treated with either HC or CA. The proportion of HC patients (n=102) who used Class I /III AADs at 12 and 18 months was significantly less (33.3% and 36.3%, respectively) than baseline (84.3%; P<0.001). In LSPAF patients who underwent HC (n=38), AADs use was 29.0% through 18 months follow-up versus 71.1% at baseline (P<0.001). Conclusions: HC reduced AF symptoms, significantly improved QOL, and reduced AAD use in patients with PersAF and LSPAF. ClinicalTrialsgov Identifier: NCT01984346.

Hybrid epicardial-endocardial ablation for long-standing persistent atrial fibrillation: A subanalysis of the CONVERGE Trial.

Background: Favorable clinical outcomes are difficult to achieve in long-standing persistent atrial fibrillation (LSPAF) with catheter ablation (CA). The CONVERGE (Convergence of Epicardial and Endocardial Ablation for the Treatment of Symptomatic Persistent Atrial FIbrillation) trial evaluated the effectiveness of hybrid convergent (HC) ablation vs endocardial CA. Objective: The study sought to evaluate the safety and effectiveness of HC vs CA in the LSPAF subgroup from the CONVERGE trial. Methods: The CONVERGE trial was a prospective, multicenter, randomized trial that enrolled 153 patients at 27 sites. A post hoc analysis was performed on LSPAF patients. The primary effectiveness was freedom from atrial arrhythmias off new or increased dose of previously failed or intolerant antiarrhythmic drugs (AADs) through 12 months. The primary safety endpoint was major adverse event incidence through 30 days with HC. Key secondary effectiveness measures included (1) percent of patients achieving ≥90% AF burden reduction vs baseline and (2) AF freedom. Results: Sixty-five patients (42.5% of total enrollment) had LSPAF; 38 in HC and 27 in CA. Primary effectiveness was 65.8% (95% confidence interval [CI] 50.7%-80.9%) with HC vs 37.0% (95% CI 5.1%-52.4%) with CA (P = .022). Through 18 months, these rates were 60.5% (95% CI 50.0%-76.1%) with HC vs 25.9% (95% CI 9.4%-42.5%) with CA (P = .006). Secondary effectiveness rates were higher than CA with HC at 12 and 18 months. Freedom from atrial arrhythmias off AADs was 52.6% (95% CI 36.8%-68.5%) and 47.4% (95% CI 31.5%-63.2%) with HC at 12 and 18 months vs 25.9% (95% CI 9.4%-42.5%) and 22.2% (95% CI 6.5%-37.9%) with CA, respectively (12 months: P = .031; 18 months: P = .038). Three (7.9%) major adverse events occurred within 30 days of HC. Conclusion: Post hoc analysis demonstrated effectiveness and acceptable safety of HC compared with CA in LSPAF.

Expression of a germline variant in the N-terminal domain of the human DNA glycosylase NTHL1 induces cellular transformation without impairing enzymatic function or substrate specificity.

Oxidatively-induced DNA damage, widely accepted as a key player in the onset of cancer, is predominantly repaired by base excision repair (BER). BER is initiated by DNA glycosylases, which locate and remove damaged bases from DNA. NTHL1 is a bifunctional DNA glycosylase in mammalian cells that predominantly removes oxidized pyrimidines. In this study, we investigated a germline variant in the N-terminal domain of NTHL1, R33K. Expression of NTHL1 R33K in human MCF10A cells resulted in increased proliferation and anchorage-independent growth compared to NTHL1 WT-expressing cells. However, wt-NTHL1 and R33K-NTHL1 exhibited similar substrate specificity, excision kinetics, and enzyme turnover in vitro and in vivo. The results of this study indicate an important function of R33 in BER that is disrupted by the R33K mutation. Furthermore, the cellular transformation induced by R33K-NTHL1 expression suggests that humans harboring this germline variant may be at increased risk for cancer incidence.

The lyase activity of bifunctional DNA glycosylases and the 3'-diesterase activity of APE1 contribute to the repair of oxidized bases in nucleosomes.

The vast majority of oxidized bases that form in DNA are subject to base excision repair (BER). The DNA intermediates generated during successive steps in BER may prove mutagenic or lethal, making it critical that they be 'handed' from one BER enzyme to the next in a coordinated fashion. Here, we report that the handoff of BER intermediates that occurs during the repair of naked DNA substrates differs significantly from that in nucleosomes. During BER of oxidized bases in naked DNA, products generated by the DNA glycosylase NTHL1 were efficiently processed by the downstream enzyme, AP-endonuclease (APE1). In nucleosomes, however, NTHL1-generated products accumulated to significant levels and persisted for some time. During BER of naked DNA substrates, APE1 completely bypasses the inefficient lyase activity of NTHL1. In nucleosomes, the NTHL1-associated lyase contributes to BER, even in the presence of APE1. Moreover, in nucleosomes but not in naked DNA, APE1 was able to process NTHL1 lyase-generated substrates just as efficiently as it processed abasic sites. Thus, the lyase activity of hNTHL1, and the 3' diesterase activity of APE1, which had been seen as relatively dispensable, may have been preserved during evolution to enhance BER in chromatin.

Intermittent anticoagulation guided by continuous atrial fibrillation burden monitoring using dual-chamber pacemakers and implantable cardioverter-defibrillators: Results from the Tailored Anticoagulation for Non-Continuous Atrial Fibrillation (TACTIC-AF) pilot study.

BACKGROUND: Chronic anticoagulation is recommended for atrial fibrillation (AF) patients with thromboembolic risk factors regardless of AF duration/frequency. Continuous rhythm assessment with pacemakers (PMs)/implantable cardioverter-defibrillators (ICDs) and use of direct-acting oral anticoagulants (DOACs) may allow anticoagulation only around AF episodes, reducing bleeding without increasing thromboembolic risk. OBJECTIVE: The purpose of this study was to evaluate the feasibility/safety of intermittent DOAC use guided by continuous remote AF monitoring via dual-chamber PMs or ICDs. METHODS: Patients with nonpermanent AF, current DOAC use, CHADS2 score ≤3, a St. Jude Medical dual-chamber PM or ICD, and rare AF episodes were followed with biweekly and AF-alert based remote transmissions. Patients free of AF episodes lasting ≥6 minutes with a total AF burden <6 hours/day for 30 consecutive days discontinued DOAC. If AF burden surpassed these limits, DOAC was restarted and/or continued. Total days on DOAC and adverse events were assessed. RESULTS: Among 48 patients (mean age 71.3 years; 65% male; 79% paroxysmal AF; 87% CHADS2 score 1-2), 14,826 days of monitoring were completed. Patients used DOACs for 3763 days, representing a 74.6% reduction in anticoagulation time compared to chronic administration. Adverse events included 2 gastrointestinal bleeds (both on DOAC), 1 fatal intracerebral bleed (off DOAC), and no thromboembolic/stroke events. CONCLUSION: Among patients with rare AF episodes and low-to-moderate stroke risk, PM/ICD-guided DOAC administration is feasible and decreased anticoagulation utilization by 75%. Few adverse events occurred, although the study was not powered to assess these outcomes. PM/ICD-guided DOAC administration may prove a viable alternative to chronic anticoagulation. Future studies are warranted.

Disorganized attachment in infancy: a review of the phenomenon and its implications for clinicians and policy-makers.

Disorganized/Disoriented (D) attachment has seen widespread interest from policy makers, practitioners, and clinicians in recent years. However, some of this interest seems to have been based on some false assumptions that (1) attachment measures can be used as definitive assessments of the individual in forensic/child protection settings and that disorganized attachment (2) reliably indicates child maltreatment, (3) is a strong predictor of pathology, and (4) represents a fixed or static "trait" of the child, impervious to development or help. This paper summarizes the evidence showing that these four assumptions are false and misleading. The paper reviews what is known about disorganized infant attachment and clarifies the implications of the classification for clinical and welfare practice with children. In particular, the difference between disorganized attachment and attachment disorder is examined, and a strong case is made for the value of attachment theory for supportive work with families and for the development and evaluation of evidence-based caregiving interventions.

Validation of a defibrillation lead ventricular volume measurement compared to three-dimensional echocardiography.

BACKGROUND: There is increasing evidence that using frequent invasive measures of pressure in patients with heart failure results in improved outcomes compared to traditional measures. Admittance, a measure of volume derived from preexisting defibrillation leads, is proposed as a new technique to monitor cardiac hemodynamics in patients with an implantable defibrillator. OBJECTIVE: The purpose of this study was to evaluate the accuracy of a new ventricular volume sensor (VVS, CardioVol) compared with 3-dimenssional echocardiography (echo) in patients with an implantable defibrillator. METHODS: Twenty-two patients referred for generator replacement had their defibrillation lead attached to VVS to determine the level of agreement to a volume measurement standard (echo). Two opposite hemodynamic challenges were sequentially applied to the heart (overdrive pacing and dobutamine administration) to determine whether real changes in hemodynamics could be reliably and repeatedly assessed with VVS. Equivalence of end-diastolic volume (EDV) and stroke volume (SV) determined by both methods was also assessed. RESULTS: EDV and SV were compared using VVS and echo. VVS tracked expected physiologic trends. EDV was modulated -10% by overdrive pacing (14 mL). SV was modulated -13.7% during overdrive pacing (-6 mL) and increased over baseline +14.6% (+8 mL) with dobutamine. VVS and echo mean EDVs were found statistically equivalent, with margin of equivalence 13.8 mL (P <.05). Likewise, mean SVs were found statistically equivalent with margin of equivalence 15.8 mL (P <.05). CONCLUSION: VVS provides an accurate method for ventricular volume assessment using chronically implanted defibrillator leads and is statistically equivalent to echo determination of mean EDV and SV.

New insight on intergenerational attachment from a relationship-based analysis.

Research on attachment transmission has focused on variable-centered analyses, where hypotheses are tested by examining linear associations between variables. The purpose of this study was to apply a relationship-centered approach to data analysis, where adult states of mind, maternal sensitivity, and infant attachment were conceived as being three components of a single, intergenerational relationship. These variables were assessed in 90 adolescent and 99 adult mother-infant dyads when infants were 12 months old. Initial variable-centered analyses replicated the frequently observed associations between these three core attachment variables. Relationship-based, latent class analyses then revealed that the most common pattern among young mother dyads featured maternal unresolved trauma, insensitive interactive behavior, and disorganized infant attachment (61%), whereas the most prevalent adult mother dyad relationship pattern involved maternal autonomy, sensitive maternal behavior, and secure infant attachment (59%). Three less prevalent relationship patterns were also observed. Moderation analyses revealed that the adolescent-adult mother distinction differentiated between secure and disorganized intergenerational relationship patterns, whereas experience of traumatic events distinguished between disorganized and avoidant patterns. Finally, socioeconomic status distinguished between avoidant and secure patterns. Results emphasize the value of a relationship-based approach, adding an angle of understanding to the study of attachment transmission.

The Human Ligase IIIα-XRCC1 Protein Complex Performs DNA Nick Repair after Transient Unwrapping of Nucleosomal DNA.

Reactive oxygen species generate potentially cytotoxic and mutagenic lesions in DNA, both between and within the nucleosomes that package DNA in chromatin. The vast majority of these lesions are subject to base excision repair (BER). Enzymes that catalyze the first three steps in BER can act at many sites in nucleosomes without the aid of chromatin-remodeling agents and without irreversibly disrupting the host nucleosome. Here we show that the same is true for a protein complex comprising DNA ligase IIIα and the scaffolding protein X-ray repair cross-complementing protein 1 (XRCC1), which completes the fourth and final step in (short-patch) BER. Using in vitro assembled nucleosomes containing discretely positioned DNA nicks, our evidence indicates that the ligase IIIα-XRCC1 complex binds to DNA nicks in nucleosomes only when they are exposed by periodic, spontaneous partial unwrapping of DNA from the histone octamer; that the scaffolding protein XRCC1 enhances the ligation; that the ligation occurs within a complex that ligase IIIα-XRCC1 forms with the host nucleosome; and that the ligase IIIα-XRCC1-nucleosome complex decays when ligation is complete, allowing the host nucleosome to return to its native configuration. Taken together, our results illustrate ways in which dynamic properties intrinsic to nucleosomes may contribute to the discovery and efficient repair of base damage in chromatin.

A brief simulation intervention increasing basic science and clinical knowledge.

BACKGROUND: The United States Medical Licensing Examination (USMLE) is increasing clinical content on the Step 1 exam; thus, inclusion of clinical applications within the basic science curriculum is crucial. Including simulation activities during basic science years bridges the knowledge gap between basic science content and clinical application. PURPOSE: To evaluate the effects of a one-off, 1-hour cardiovascular simulation intervention on a summative assessment after adjusting for relevant demographic and academic predictors. METHODS: This study was a non-randomized study using historical controls to evaluate curricular change. The control group received lecture (n l=515) and the intervention group received lecture plus a simulation exercise (n l+s=1,066). Assessment included summative exam questions (n=4) that were scored as pass/fail (≥75%). USMLE-style assessment questions were identical for both cohorts. Descriptive statistics for variables are presented and odds of passage calculated using logistic regression. RESULTS: Undergraduate grade point ratio, MCAT-BS, MCAT-PS, age, attendance at an academic review program, and gender were significant predictors of summative exam passage. Students receiving the intervention were significantly more likely to pass the summative exam than students receiving lecture only (P=0.0003). DISCUSSION: Simulation plus lecture increases short-term understanding as tested by a written exam. A longitudinal study is needed to assess the effect of a brief simulation intervention on long-term retention of clinical concepts in a basic science curriculum.

Mechanisms and Consequences of Double-Strand DNA Break Formation in Chromatin.

All organisms suffer double-strand breaks (DSBs) in their DNA as a result of exposure to ionizing radiation. DSBs can also form when replication forks encounter DNA lesions or repair intermediates. The processing and repair of DSBs can lead to mutations, loss of heterozygosity, and chromosome rearrangements that result in cell death or cancer. The most common pathway used to repair DSBs in metazoans (non-homologous DNA end joining) is more commonly mutagenic than the alternative pathway (homologous recombination mediated repair). Thus, factors that influence the choice of pathways used DSB repair can affect an individual's mutation burden and risk of cancer. This review describes radiological, chemical, and biological mechanisms that generate DSBs, and discusses the impact of such variables as DSB etiology, cell type, cell cycle, and chromatin structure on the yield, distribution, and processing of DSBs. The final section focuses on nucleosome-specific mechanisms that influence DSB production, and the possible relationship between higher order chromosome coiling and chromosome shattering (chromothripsis).

Distress regulation in infancy: attachment and temperament in the context of acute pain.

OBJECTIVE: The relationship between attachment, temperamental fear, and pain-related distress was examined in a sample of 130 caregiver-infant dyads to explore the differential susceptibility hypothesis. METHOD: Infant distress was measured during routine immunization at 12 months, and attachment and temperamental fear were measured at 12 to 18 months (meanage = 13.74, SD = 1.35) using the Strange Situation Procedure and parent-rated Infant Behavior Questionnaire-Revised, respectively. RESULTS: Immediately before immunization, avoidant infants exhibited significantly less distress than secure infants. Temperamental fear moderated the relationship between attachment and regulation; under conditions of high temperamental fear, avoidant infants regulated distress more slowly than secure infants, whereas under conditions of low temperamental fear, secure infants regulated distress more slowly than avoidant and disorganized infants. CONCLUSION: The findings suggest that attachment interacts with extremes in temperamental fear to produce differences in the regulation of distress. The results partially support the differential susceptibility hypothesis.

Nucleosomes suppress the formation of double-strand DNA breaks during attempted base excision repair of clustered oxidative damages.

Exposure to ionizing radiation can produce multiple, clustered oxidative lesions in DNA. The near simultaneous excision of nearby lesions in opposing DNA strands by the base excision repair (BER) enzymes can produce double-strand DNA breaks (DSBs). This attempted BER accounts for many of the potentially lethal or mutagenic DSBs that occur in vivo. To assess the impact of nucleosomes on the frequency and pattern of BER-dependent DSB formation, we incubated nucleosomes containing oxidative damages in opposing DNA strands with selected DNA glycosylases and human apurinic/apyrimidinic endonuclease 1. Overall, nucleosomes substantially suppressed DSB formation. However, the degree of suppression varied as a function of (i) the lesion type and DNA glycosylase tested, (ii) local sequence context and the stagger between opposing strand lesions, (iii) the helical orientation of oxidative lesions relative to the underlying histone octamer, and (iv) the distance between the lesion cluster and the nucleosome edge. In some instances the binding of a BER factor to one nucleosomal lesion appeared to facilitate binding to the opposing strand lesion. DSB formation did not invariably lead to nucleosome dissolution, and in some cases, free DNA ends resulting from DSB formation remained associated with the histone octamer. These observations explain how specific structural and dynamic properties of nucleosomes contribute to the suppression of BER-generated DSBs. These studies also suggest that most BER-generated DSBs will occur in linker DNA and in genomic regions associated with elevated rates of nucleosome turnover or remodeling.

Understanding sensitivity: lessons learned from the legacy of Mary Ainsworth.

On the basis of extensive home observations, Ainsworth proposed that a mother's sensitivity to her infant's signals is the primary determinant of attachment security. Although subsequent research has found a relationship between sensitivity and attachment security, the effect sizes are much smaller than those reported by Ainsworth. In addition to the amount of observation time that might account for the effect size difference, we consider Ainsworth's focus on understanding the organizational structure of relationships. We coded 30 minute video records of interactions between 64 mother-infant dyads from semi-structured home observations conducted at 10 months of age. Coding consisted of writing a narrative summary of the interactions, annotating a completion of Ainsworth's rating scales of acceptance, accessibility, cooperation and sensitivity and then describing the mother's behavior using the Maternal Behaviour Q-set. Sensitivity scores derived from the Q-sort descriptions were robustly related (r = .65) to secure-insecure classifications in the Strange Situation conducted at 13 months. We reflect on the process of assessing Ainsworth's construct of sensitivity.

Contribution of DNA unwrapping from histone octamers to the repair of oxidatively damaged DNA in nucleosomes.

Reactive oxygen species generate ~20,000 oxidative lesions in the DNA of every cell, every day. Most of these lesions are located within nucleosomes, which package DNA in chromatin and impede base excision repair (BER). We demonstrated previously that periodic, spontaneous partial unwrapping of DNA from the underlying histone octamer enables BER enzymes to bind to oxidative lesions that would otherwise be sterically inaccessible. In the present study, we asked if these periodic DNA unwrapping events are frequent enough to account for the estimated rates of BER in vivo. We measured rates of excision of oxidative lesions from sites in nucleosomes that are accessible only during unwrapping episodes. Using reaction conditions appropriate for presteady-state kinetic analyses, we derived lesion exposure rates for both 601 and 5S rDNA-based nucleosomes. Although DNA unwrapping-mediated exposure of a lesion ~16NT from the nucleosome edge occurred ~7-8 times per minute, exposure rates fell dramatically for lesions located 10 or more NT further in from the nucleosome edge. The rates likely are too low to account for observed rates of BER in cells. Thus, chromatin remodeling, either BER-specific or that associated with transcription, replication, or other DNA repair processes, probably contributes to efficient BER in vivo.

Rules of engagement for base excision repair in chromatin.

Most of the DNA in eukaryotes is packaged in tandemly arrayed nucleosomes that, together with numerous DNA- and nucleosome-associated enzymes and regulatory factors, make up chromatin. Chromatin modifying and remodeling agents help regulate access to selected DNA segments in chromatin, thereby facilitating transcription and DNA replication and repair. Studies of nucleotide excision repair (NER), single strand break repair (SSBR), and the homology-directed repair (HDR), and non-homologous end-joining (NHEJ) double strand break repair pathways have led to an "access-repair-restore" paradigm, in which chromatin in the vicinity of damaged DNA is disrupted, thereby enabling efficient repair and the subsequent repackaging of DNA into nucleosomes. When damage is extensive, these repair processes are accompanied by cell cycle checkpoint activation, which provides cells with sufficient time to either complete the repair or initiate apoptosis. It is not clear, however, if base excision repair (BER) of the ~20,000 or more oxidative DNA damages that occur daily in each nucleated human cell can be viewed through this same lens. Until recently, we did not know if BER requires or is accompanied by nucleosome disruption, and it is not yet clear that anything short of overwhelming oxidative damage (resulting in the shunting of DNA substrates into other repair pathways) results in checkpoint activation. This review highlights studies of how oxidatively damaged DNA in nucleosomes is discovered and repaired, and offers a working model of events associated with BER in chromatin that we hope will have heuristic value.

Nucleosome disruption by DNA ligase III-XRCC1 promotes efficient base excision repair.

Each day, approximately 20,000 oxidative lesions form in the DNA of every nucleated human cell. The base excision repair (BER) enzymes that repair these lesions must function in a chromatin milieu. We have determined that the DNA glycosylase hNTH1, apurinic endonuclease (APE), and DNA polymerase ß (Pol ß), which catalyze the first three steps in BER, are able to process their substrates in both 601- and 5S ribosomal DNA (rDNA)-based nucleosomes. hNTH1 formed a discrete ternary complex that was displaced by the addition of APE, suggesting an orderly handoff of substrates from one enzyme to the next. In contrast, DNA ligase IIIα-XRCC1, which completes BER, was appreciably active only at concentrations that led to nucleosome disruption. Ligase IIIα-XRCC1 was also able to bind and disrupt nucleosomes containing a single base gap and, because of this property, enhanced both its own activity and that of Pol ß on nucleosome substrates. Collectively, these findings provide insights into rate-limiting steps that govern BER in chromatin and reveal a unique role for ligase IIIα-XRCC1 in enhancing the efficiency of the final two steps in the BER of lesions in nucleosomes.

Non-specific DNA binding interferes with the efficient excision of oxidative lesions from chromatin by the human DNA glycosylase, NEIL1.

Although DNA in eukaryotes is packaged in nucleosomes, it remains vulnerable to oxidative damage that can result from normal cellular metabolism, ionizing radiation, and various chemical agents. Oxidatively damaged DNA is repaired in a stepwise fashion via the base excision repair (BER) pathway, which begins with the excision of damaged bases by DNA glycosylases. We reported recently that the human DNA glycosylase hNTH1 (human Endonuclease III), a member of the HhH GpG superfamily of glycosylases, can excise thymine glycol lesions from nucleosomes without requiring or inducing nucleosome disruption; optimally oriented lesions are excised with an efficiency approaching that seen for naked DNA [1]. To determine if this property is shared by human DNA glycoylases in the Fpg/Nei family, we investigated the activity of NEIL1 on defined nucleosome substrates. We report here that the cellular concentrations and apparent k(cat)/K(M) ratios for hNTH1 and NEIL1 are similar. Additionally, after adjustment for non-specific DNA binding, hNTH1 and NEIL1 proved to have similar intrinsic activities toward nucleosome substrates. However, NEIL1 and hNTH1 differ in that NEIL1 binds undamaged DNA far more avidly than hNTH1. As a result, hNTH1 is able to excise both accessible and sterically occluded lesions from nucleosomes at physiological concentrations, while the high non-specific DNA affinity of NEIL1 would likely hinder its ability to process sterically occluded lesions in cells. These results suggest that, in vivo, NEIL1 functions either at nucleosome-free regions (such as those near replication forks) or with cofactors that limit its non-specific binding to DNA.

Validation of a short version of the maternal behavior Q-set applied to a brief video record of mother-infant interaction.

A 25 item version of the maternal behavior Q-set (MBQS) was validated with 40 adolescent mother-infant dyads. Observations were made from 10 min play interactions when infants were 10 months old. Results show that the short MBQS is reliable (r(i)=.94), is related to assessments using the full MBQS at 6 months (r=.35), to cognitive development at 10 and 15 months (r=.48), and attachment security at 15 months (r=.34), indicating appropriate psychometric characteristics.

Similarities and differences in mothers' and observers' ratings of infant security on the Attachment Q-Sort.

This study examined the similarities and differences in maternal and observer Attachment Behavior Q-Sort ratings (AQS; Waters, 1995) and their relations to dimensions of the developmental ecology - maternal sensitivity, infant irritability, parental stress and psychosocial risk. Data was gathered from low risk (adult mothers; N=44) and high risk mother-infant dyads (adolescent mothers; N=83) when infants were aged 6, 10 and 15 months old, attachment being assessed at 15 months by both mothers and independent observers. A common factor was extracted from both sorts and served to operationalize the similarities between mother and observer ratings. Regressions were conducted to extract maternal and observer AQS scores that were unrelated to each other to represent the difference between the two sorts. Correlation analyses indicated that the common AQS factor was moderately linked to maternal sensitivity and parental stress, and showed a weak association to psychosocial risk and infant irritability. Residual maternal scores showed greater correlations with infant irritability and parental stress than did observer residual scores. Observer scores showed a greater correlation with psychosocial risk than maternal scores. Results suggest that common AQS variance presents a pattern of associations with ecological variables that is coherent with attachment research. Variance related to irritability, stress and risk appear to drive the differences between maternal and observer observations.