RNA-directed DNA repair and antibody somatic hypermutation.

Somatic hypermutation at antibody loci affects both deoxyadenosine-deoxythymidine (A/T) and deoxycytidine-deoxyguanosine (C/G) pairs. Deamination of C to deoxyuridine (U) by activation-induced deaminase (AID) explains how mutation at C/G pairs is potentiated. Mutation at A/T pairs is triggered during the initial stages of repair of AID-generated U lesions and occurs through an as yet unknown mechanism in which polymerase η has a major role. Recent evidence confirms that human polymerase η can act as a reverse transcriptase. Here, we compare the popular suggestion of mutation at A/T pairs through nucleotide mispairing (owing to polymerase error) during short-patch repair synthesis with the alternative proposal of mutation at A/T pairs through RNA editing and RNA-directed DNA repair.

PI3 Kinase and FOXO1 Transcription Factor Activity Differentially Control B Cells in the Germinal Center Light and Dark Zones.

Phosphatidylinositol 3' OH kinase (PI3K) signaling and FOXO transcription factors play opposing roles at several B cell developmental stages. We show here abundant nuclear FOXO1 expression in the proliferative compartment of the germinal center (GC), its dark zone (DZ), and PI3K activity, downregulating FOXO1, in the light zone (LZ), where cells are selected for further differentiation. In the LZ, however, FOXO1 was expressed in a fraction of cells destined for DZ reentry. Upon FOXO1 ablation or induction of PI3K activity, GCs lost their DZ, owing at least partly to downregulation of the chemokine receptor CXCR4. Although this prevented proper cyclic selection of cells in GCs, somatic hypermutation and proliferation were maintained. Class switch recombination was partly lost due to a failure of switch region targeting by activation-induced deaminase (AID).

Decreased Alpha Klotho Expression in Placentas Exposed to Severe Maternal Vascular Malperfusion.

BACKGROUND: Placental maternal vascular malperfusion (MVM) is characterized by accelerated villous maturation and has been associated with a decrease in the antiaging protein, alpha-klotho (AK). Our aim was to characterize AK protein and gene expression in the placenta and fetal organs. METHODS: We utilized 2 cohorts. First, we characterized AK protein expression in an autopsy cohort where cases were defined as MVM as the cause of fetal death compared to a stillborn control population. Second, we characterized placental and umbilical cord blood AK gene expression in a liveborn population with and without MVM. RESULTS: We found decreased protein expression in the villous trophoblastic cells of placentas exposed to severe MVM and decreased AK gene expression in placental tissue exposed to MVM. We did not see any statistically significant differences in fetal organ or umbilical cord blood AK expression based on the presence or absence of MVM. Furthermore, in liveborn infants, we also found increased odds of preterm birth with lower placental AK expression. CONCLUSIONS: Decreased AK gene and protein expression in the placenta in the setting of MVM is consistent with the theory of placental aging in MVM and is associated with increased odds of preterm birth.

Association of Opioid Disposal Practices with Parental Education and a Home Opioid Disposal Kit Following Pediatric Ambulatory Surgery.

BACKGROUND: The majority of opioid analgesics prescribed for pain after ambulatory pediatric surgery remain unused. Most parents do not dispose of these leftover opioids or dispose of them in an unsafe manner. We aimed to evaluate the association of optimal opioid disposal with a multidisciplinary quality improvement (QI) initiative that proactively educated parents about the importance of optimal opioid disposal practices and provided a home opioid disposal kit before discharge after pediatric ambulatory surgery. METHODS: Opioid disposal behaviors were assessed during a brief telephone interview pre- (Phase I) and post-implementation (Phase II) after surgery. For each phase, we aimed to contact the parents of 300 pediatric patients ages 0 to 17 years who were prescribed an opioid after an ambulatory surgery. The QI initiative included enhanced education and a home opioid disposal kit including DisposeRX®, a medication disposal packet that renders medications inert within a polymeric gel when mixed with water. Weighted segmented regression models evaluated the association between the QI initiative and outcomes. We considered the association between the QI initiative and outcome significant if the beta coefficient for the change in intercept between the end of Phase I and the beginning of Phase II was significant. Safe opioid disposal and any opioid disposal were evaluated as secondary outcomes. RESULTS: The analyzed sample contained 161 pediatric patients in Phase I and 190 pediatric patients in Phase II. Phase II (post-QI initiative) cohort compared to Phase I cohort reported higher rates of optimal (58%, n = 111/190 vs 11%, n = 18/161) and safe (66%, n = 125/190 vs 34%, n = 55/161) opioid disposal. Weighted segmented regression analyses demonstrated significant increases in the odds of optimal (odds ratio [OR], 26.5, 95% confidence interval [CI], 4.0-177.0) and safe (OR, 4.4, 95% CI, 1.1-18.4) opioid disposal at the beginning of Phase II compared to the end of Phase I. The trends over time (slopes) within phases were nonsignificant and close to 0. The numbers needed to be exposed to achieve one new disposal event were 2.2 (95% CI, 1.4-3.7]), 3.1 (95% CI, 1.6-7.4), and 4.3 (95% CI, 1.7-13.6) for optimal, safe, and any disposal, respectively. CONCLUSIONS: A multidisciplinary approach to educating parents on the importance of safe disposal of leftover opioids paired with dispensing a convenient opioid disposal kit was associated with increased odds of optimal opioid disposal.

Impact of social vulnerability index on severity of obstructive sleep apnea: Insights from drug-induced sleep endoscopy.

OBJECTIVES: To examine the association between neighborhood-level social vulnerability on the severity of obstructive sleep apnea (OSA) in patients undergoing drug-induced sleep endoscopy (DISE). STUDY DESIGN: Single center retrospective cohort study. METHODS: We conducted a retrospective chart review of patients >18 years of age that underwent DISE from July 2016 to July 2022. Patient addresses were geocoded with geographic information systems, and spatial overlays were used to assign census-tract level social vulnerability index (SVI) scores in the four sub-themes: Socioeconomic (theme 1), Household Composition/Disability (theme 2), Minority Status/Language (theme 3), and Housing/Transportation (theme 4). RESULTS: The study included 165 patients (61.2 years ± 11.6; 31.0 BMI ± 6.1, 102 male, 63 female). Mild OSA was present in13 patients; 55 patients had moderate OSA; and 97 patients had severe OSA. A higher SVI value in minority status and language, and a higher BMI both predicted an increased Apnea Hypopnea Index (AHI) (p = 0.042, and <0.001, respectively) in the multivariate model; whereas, race, age, gender, or the other three SVI sub-theme values were not predictive. CONCLUSION: Adults residing in areas of greater social vulnerability - specifically a larger minority presence or English as a second language - and patients who are obese are more likely to have more severe OSA. There was no correlation, however, between obesity and residence in an area of high SVI. These results suggest that both neighborhood conditions and obesity are associated with OSA severity. This elevated risk has potential implications for diagnostic testing, clinic follow-ups, screening, and treatment plans for adults residing in disenfranchised neighborhoods. LEVEL OF EVIDENCE: IV.

Measures of Fetal Growth and Cardiac Structure in Stillbirths With Placental Maternal Vascular Malperfusion: Evidence for Heart Weight Sparing and Structural Cardiac Alterations in Humans.

BACKGROUND: Placental maternal vascular malperfusion (MVM) is associated with fetal growth restriction (FGR). While FGR increases the risk of cardiovascular disease, the impact of MVM on fetal cardiac structure is understudied. METHODS: We utilized a cohort of autopsied stillbirths; 29 with MVM as the cause of death and 21 with a cause of death unrelated to MVM. Fetal and organ weights and heart measurements were standardized by gestational age and compared between MVM and non-MVM stillbirths. Differences in standardized fetal organ and cardiac measures as compared to standardized fetal body weight were calculated to account for body size. RESULTS: MVM stillbirths had smaller organ and heart weights than non-MVM stillbirths; however, after accounting for gestational age, heart weight was the least affected among all organs. In an analysis of organ weights relative to body size, heart weights were 0.31 standard deviations (SD) larger than expected relative to body weight (95% CI: 0.04, 0.57). Right and left ventricle thicknesses and mitral valve circumference were also larger than expected relative to body weight. CONCLUSION: Stillbirth due to MVM was associated with relative sparing of heart weight and other heart measurements. The significance of these findings in liveborn infants needs further study.

Anatomy of the Ductus Arteriosus in Fetal Autopsies: Correlations With Placental Pathology and Cause of Death.

BACKGROUND: Differences in the shape of the ductus arteriosus (DA), an important vascular shunt between the pulmonary artery and aorta, may reflect fetoplacental blood flow. Our aim was to examine tapering of the DA in a fetal autopsy population and correlate it with placental pathology and cause of death (COD). METHODS: This autopsy case control study of stillborn fetuses selected cases (tapered DA) and consecutive age-matched controls (no DA tapering) between January 2017 and January 2022. We abstracted demographic and clinical data from pathology reports. Autopsy data included COD and histologic evidence of fetal hypoxia. Placental pathology included umbilical cord abnormalities, acute and chronic inflammation, fetal vascular malperfusion (FVM), and maternal vascular malperfusion (MVM). RESULTS: We identified 50 cases and 50 controls. Gestational age ranged from 18 to 38 weeks. Maternal and fetal demographic characteristics did not differ significantly between cases and controls. COD related to an umbilical cord accident/FVM was significantly more prevalent in cases vs controls (46% vs 26%, P = .037), and FVM in the placenta, regardless of COD, trended higher in cases than controls. CONCLUSION: Tapering of the DA is present in stillborn fetuses and associated with COD related to fetal vascular blood flow obstruction.

Leftover Opioid Analgesics and Disposal Following Ambulatory Pediatric Surgeries in the Context of a Restrictive Opioid-Prescribing Policy.

BACKGROUND: Opioid analgesics are commonly prescribed for postoperative analgesia following pediatric surgery and often result in leftover opioid analgesics in the home. To reduce the volume of leftover opioids and overall community opioid burden, the State of Tennessee enacted a policy to reduce initial opioid prescribing to a 3-day supply for most acute pain incidents. We aimed to evaluate the extent of leftover opioid analgesics following pediatric ambulatory surgeries in the context of a state-mandated restrictive opioid-prescribing policy. We also aimed to evaluate opioid disposal rates, methods of disposal, and reasons for nondisposal. METHODS: Study personnel contacted the parents of 300 pediatric patients discharged with an opioid prescription following pediatric ambulatory surgery. Parents completed a retrospective telephone survey regarding opioid use and disposal. Data from the survey were combined with data from the medical record to evaluate proportion of opioid doses prescribed that were left over. RESULTS: The final analyzable sample of 185 patients (62% response rate) were prescribed a median of 12 opioid doses (interquartile range [IQR], 12-18), consumed 2 opioid doses (IQR, 0-4), and had 10 opioid doses left over (IQR, 7-13). Over 90% (n = 170 of 185) of parents reported they had leftover opioid analgesics, with 83% of prescribed doses left over. A significant proportion (29%, n = 54 of 185) of parents administered no prescribed opioids after surgery. Less than half (42%, n = 71 of 170) of parents disposed of the leftover opioid medication, most commonly by flushing down the toilet, pouring down the sink, or throwing in the garbage. Parents retaining leftover opioids (53%, n = 90 of 170) were most likely to keep them in an unlocked location (68%, n = 61 of 90). Parents described forgetfulness and worry that their child will experience pain in the future as primary reasons for not disposing of the leftover opioid medication. CONCLUSIONS: Despite Tennessee's policy aimed at reducing leftover opioids, a significant proportion of prescribed opioids were left over following pediatric ambulatory surgeries. A majority of parents did not engage in safe opioid disposal practices. Given the safety risks related to leftover opioids in the home, further interventions to improve disposal rates and tailor opioid prescribing are warranted after pediatric surgery.

Financial and Clinical Ramifications of Introducing a Novel Pediatric Enhanced Recovery After Surgery Pathway for Pediatric Complex Hip Reconstructive Surgery.

BACKGROUND: Enhanced recovery after surgery pathways confer significant perioperative benefits to patients and are currently well described for adult patients undergoing a variety of surgical procedures. Robust data to support enhanced recovery pathway use in children are relatively lacking in the medical literature, though clinical benefits are reported in targeted pediatric surgical populations. Surgery for complex hip pathology in the adolescent patient is painful, often requiring prolonged courses of opioid analgesia. Postoperative opioid-related side effects may lead to prolonged recovery periods and suboptimal postoperative physical function. Excessive opioid use in the perioperative period is also a major risk factor for the development of opioid misuse in adolescents. Perioperative opioid reduction strategies in this vulnerable population will help to mitigate this risk. METHODS: A total of 85 adolescents undergoing complex hip reconstructive surgery were enrolled into an enhanced recovery after surgery pathway (October 2015 to December 2018) and were compared with 110 patients undergoing similar procedures in previous years (March 2010 to September 2015). The primary outcome was total perioperative opioid consumption. Secondary outcomes included hospital length of stay, postoperative nausea, intraoperative blood loss, and other perioperative outcomes. Total cost of care and specific charge sectors were also assessed. Segmented regression was used to assess the effects of pathway implementation on outcomes, adjusting for potential confounders, including the preimplementation trend over time. RESULTS: Before pathway implementation, there was a significant downward trend over time in average perioperative opioid consumption (-0.10 mg total morphine equivalents/90 days; 95% confidence interval [CI], -0.20 to 0.00) and several secondary perioperative outcomes. However, there was no evidence that pathway implementation by itself significantly altered the prepathway trend in perioperative opioid consumption (ie, the preceding trend continued). For postanesthesia care unit time, the downward trend leveled off significantly (pre: -5.25 min/90 d; 95% CI, -6.13 to -4.36; post: 1.04 min/90 d; 95% CI, -0.47 to 2.56; Change: 6.29; 95% CI, 4.53-8.06). Clinical, laboratory, pharmacy, operating room, and total charges were significantly associated with pathway implementation. There was no evidence that pathway implementation significantly altered the prepathway trend in other secondary outcomes. CONCLUSIONS: The impacts of our pediatric enhanced recovery pathway for adolescents undergoing complex hip reconstruction are consistent with the ongoing improvement in perioperative metrics at our institution but are difficult to distinguish from the impacts of other initiatives and evolving practice patterns in a pragmatic setting. The ERAS pathway helped codify and organize this new pattern of care, promoting multidisciplinary evidence-based care patterns and sustaining positive preexisting trends in financial and clinical metrics.

Variation Between and Within Hospitals in Single Injection Caudal Local Anesthetic Dose: A Report From the Pediatric Regional Anesthesia Network.

BACKGROUND: Given that variation exists in health care utilization, expenditure, and medical practice, there is a paucity of data on variation within the practice of anesthesia. The Pediatric Regional Anesthesia Network (PRAN) data lend itself to explore whether different medical practice patterns exist and if there are nerve blocks with more local anesthetic dosing variation than others. The primary aim of this study was to quantify variation in single injection caudal block dosing, and the secondary aim was to explore possible causes for variation (eg, number of blocks performed versus geographic location). METHODS: We queried the PRAN database for single injection caudal blocks in children <1 year of age. Data were analyzed for local anesthetic dose, variation within and across institutions, and possible causes. RESULTS: Mean dose of bupivacaine equivalents per kilogram (BE·kg) among sites ranged from 1.39 to 2.22 with an interdecile range (IDR) containing the mid 80% of all doses ranging from 0.21 to 1.48. Mean dose (BE·kg) was associated with site, age, weight, and local anesthetic used (all P < .0001). Cohen's F effect size estimate was 10 times higher for site (0.65) than for age (0.05) or weight (0.02). Variation (IDR) was not related to number of blocks done at each site (P = .23). Mean volume per kilogram was 0.9± ± 0.2 (mean ± ±standard deviation) and was more strongly associated with site (Cohen's F 0.3) than age (0.04) or weight (0.07). CONCLUSIONS: Wide variation in caudal local anesthetic dosing and administered volume exists. This variation is independent of the number of cases performed at each center but rather is determined by study site (ie, variation between centers) with considerable additional variation within study centers, suggesting additional variability dependent on individual practitioners. While there are legitimate reasons to vary dosing, the current approach is inconsistent and not supported by strong evidence over giving a standardized dose.

Individual short-acting opioids and the risk of opioid-related adverse events in adolescents.

PURPOSE: Hydrocodone, codeine, oxycodone, and tramadol are frequently prescribed to adolescents for moderate pain related to minor trauma or dental, surgical, or medical procedures. Pharmacokinetic and pharmacodynamic differences between these opioids could affect their relative safety. We aimed to compare occurrence of opioid-related adverse events in adolescents without cancer or other severe conditions taking hydrocodone, codeine, oxycodone, and tramadol. METHODS: Retrospective cohort study of 201 940 Tennessee Medicaid enrollees 12 to 17 years of age without cancer, other severe conditions, or evidence of substance abuse with 529 731 filled prescriptions for study opioids. Adverse events were defined as an emergency department visit, hospital admission, or death related to opioid use, confirmed by medical record review. Serious events had opioid-related escalation of care, hospitalization, or death. Propensity-score adjusted hazard ratios (HRs) were calculated with hydrocodone as the reference category. RESULTS: The incidence of opioid-related adverse events per 10 000 person-years of opioid exposure was 97.5 for hydrocodone (127 events/13 026 person-years), 91.2 for codeine (58/6,359), 229.7 for oxycodone (43/1,872), and 317.7 for tramadol (47/1479). The HRs for tramadol in comparison with hydrocodone for all and serious events were 2.98 (2.03-4.39) and 2.94 (1.81-4.75), respectively. Increased risk for tramadol was consistently present when the adverse events were restricted to those with neurologic-respiratory depression/other symptoms of possible overdose. CONCLUSION: In adolescents without cancer or other severe conditions prescribed short-acting opioids, the incidence of both all opioid-related adverse events and more serious events with opioid-related escalation of care, hospitalization, or death was consistently greater for tramadol than for hydrocodone.

The B-cell antigen receptor integrates adaptive and innate immune signals.

B cells respond to antigens by engagement of their B-cell antigen receptor (BCR) and of coreceptors through which signals from helper T cells or pathogen-associated molecular patterns are delivered. We show that the proliferative response of B cells to the latter stimuli is controlled by BCR-dependent activation of phosphoinositidyl 3-kinase (PI-3K) signaling. Glycogen synthase kinase 3ß and Foxo1 are two PI-3K-regulated targets that play important roles, but to different extents, depending on the specific mitogen. These results suggest a model for integrating signals from the innate and the adaptive immune systems in the control of the B-cell immune response.

CTCF-binding elements mediate control of V(D)J recombination.

Immunoglobulin heavy chain (IgH) variable region exons are assembled from V(H), D and J(H) gene segments in developing B lymphocytes. Within the 2.7-megabase mouse Igh locus, V(D)J recombination is regulated to ensure specific and diverse antibody repertoires. Here we report in mice a key Igh V(D)J recombination regulatory region, termed intergenic control region 1 (IGCR1), which lies between the V(H) and D clusters. Functionally, IGCR1 uses CTCF looping/insulator factor-binding elements and, correspondingly, mediates Igh loops containing distant enhancers. IGCR1 promotes normal B-cell development and balances antibody repertoires by inhibiting transcription and rearrangement of D(H)-proximal V(H) gene segments and promoting rearrangement of distal V(H) segments. IGCR1 maintains ordered and lineage-specific V(H)(D)J(H) recombination by suppressing V(H) joining to D segments not joined to J(H) segments, and V(H) to DJ(H) joins in thymocytes, respectively. IGCR1 is also required for feedback regulation and allelic exclusion of proximal V(H)-to-DJ(H) recombination. Our studies elucidate a long-sought Igh V(D)J recombination control region and indicate a new role for the generally expressed CTCF protein.

Anesthetic considerations for pediatric electroconvulsive therapy.

Electroconvulsive therapy is being used more frequently in the treatment of many chronic and acute psychiatric illnesses in children. The most common psychiatric indications for pediatric electroconvulsive therapy are refractory depression, bipolar disorder, schizophrenia, catatonia, and autism. In addition, a relatively new indication is the treatment of pediatric refractory status epilepticus. The anesthesiologist may be called upon to assist in the care of this challenging and vulnerable patient population. Unique factors for pediatric electroconvulsive therapy include the potential need for preoperative anxiolytic and inhalational induction of anesthesia, which must be weighed against the detrimental effects of anesthetic agents on the evoked seizure quality required for a successful treatment. Dexmedetomidine is likely the most appropriate preoperative anxiolytic as oral benzodiazepines are relatively contraindicated. Methohexital, though becoming less available at many institutions, remains the gold standard for induction of anesthesia for pediatric electroconvulsive therapy though ketamine, propofol, and sevoflurane are becoming increasingly viable options. Proper planning and communication between the multidisciplinary teams involved in the care of children presenting for electroconvulsive therapy treatments is vital to mitigating risks and achieving the greatest therapeutic benefit.

Is the robotic approach feasible for repair of iatrogenic injuries of the lower ureter?

OBJECTIVES: To analyze the robotic approach as treatment of iatrogenic ureteral injuries. METHODS: Medical records were reviewed for patients undergoing robotic-assisted laparoscopic ureteral reimplantation at the University of Missouri from 2009 to 2014. Patient charts were analyzed for demographics, prior abdominal surgeries, circumstances of injury, outcomes, and other relevant information. RESULTS: Nine patients met inclusion criteria. The average age was 44.6. Patients had an average of 4.3 abdominal surgeries. Injury occurred during hysterectomy (open, laparoscopic, or vaginal) in eight patients (88.9 %), five cases were laparoscopic, two utilized robotic assistance, and one injury occurred during uterosacral vault suspension. All cases were related to gynecological procedures. On average, ureteral injury was detected 17.2 days after the initial surgery and repaired 62.3 days after initial operation. The average surgical repair time was 295.9 min (range 168-498) with an average blood loss of 77.2 mL (range 20-150). Four patients required a psoas hitch, with one receiving both a psoas hitch and a Boari flap. Postoperatively, patients had an average hospital stay of 2.7 days. One patient had ileus for greater than 3 days, and another was readmitted within 30 days for pain control and antiemetics following stent removal. One patient underwent open reimplantation 3 years after original surgery for development of ureteral stricture. At follow-up, all patients had returned to baseline renal function. CONCLUSIONS: Robotic approach is feasible and a safe option for distal iatrogenic ureteral injuries occurring during gynecological procedures. Prior abdominal surgery or delayed repair does not preclude a robotic approach.

Fluoroscopically guided tunneled trans-caudal epidural catheter technique for opioid-free neonatal epidural analgesia.

Epidural analgesia confers significant perioperative advantages to neonates undergoing surgical procedures but may be very technically challenging to place using a standard interlaminar loss-of-resistance to saline technique given the shallow depth of the epidural space. Thoracic epidural catheters placed via the caudal route may reduce the risk of direct neural injury from needle placement, but often pose higher risks of infection and/or improper positioning if placed without radiographic guidance. We present a detailed method of placing a fluoroscopically guided, tunneled transcaudal epidural catheter, which may reduce both of these risks. The accuracy and precision of this technique often provides adequate analgesia to allow for opioid-free epidural infusions as well as significant reductions in systemic opioids through the perioperative period. Opioid-free analgesia using a regional anesthetic technique allows for earlier extubation and reduced perioperative sedation, which may have a less deleterious neurocognitive effect on the developing brain of the neonate.