Improving Pediatric Fellows' Feedback Skills and Confidence Through Objective Structured Examinations.

Background Medical trainees must learn how to provide effective feedback as an essential communication skill, yet few models exist for training and assessing these skills. Objective To develop an observed structured feedback examination (OSFE) to provide feedback training to pediatric fellows and assess changes in skills and self-reported confidence. Methods This educational study was conducted from 2019 to 2020 at an academic children's hospital. Our team developed the OSFE and trained standardized feedback recipients and faculty. Fellows completed baseline self-assessments (31 items) on prior exposure to feedback training, application of skills, and confidence. They then participated in the OSFE, giving feedback to a standardized recipient using a standardized scenario, and were scored by faculty and recipients using a 15-item checklist for performance. Next, fellows participated in feedback training and received individualized feedback, after which they repeated the OSFE and confidence self-assessment. Three months later, fellows completed self-assessments on confidence and application of skills and another OSFE to assess retention. Descriptive statistics and signed rank sum test were used for analysis. Results Of 60 eligible fellows, 19 participated (32%), with 100% follow-up. After training and individualized feedback, all fellows improved feedback skills as measured by OSFE performance (mean change +0.89). All items, measured on a 5-point Likert scale, were sustained 3 months later (mean change +0.92). All fellows reported improved confidence in feedback knowledge (mean change +2.07 post, +1.67 3 months post). Conclusions Feedback training using simulation and individualized feedback moderately improved fellows' performance, confidence, and 3-month retention of feedback skills.

Risk of bacterial bloodstream infection does not vary by central-line type during neutropenic periods in pediatric acute myeloid leukemia.

BACKGROUND: Bloodstream infections (BSIs) are a frequent cause of morbidity in patients with acute myeloid leukemia (AML), due in part to the presence of central venous access devices (CVADs) required to deliver therapy. OBJECTIVE: To determine the differential risk of bacterial BSI during neutropenia by CVAD type in pediatric patients with AML. METHODS: We performed a secondary analysis in a cohort of 560 pediatric patients (1,828 chemotherapy courses) receiving frontline AML chemotherapy at 17 US centers. The exposure was CVAD type at course start: tunneled externalized catheter (TEC), peripherally inserted central catheter (PICC), or totally implanted catheter (TIC). The primary outcome was course-specific incident bacterial BSI; secondary outcomes included mucosal barrier injury (MBI)-BSI and non-MBI BSI. Poisson regression was used to compute adjusted rate ratios comparing BSI occurrence during neutropenia by line type, controlling for demographic, clinical, and hospital-level characteristics. RESULTS: The rate of BSI did not differ by CVAD type: 11 BSIs per 1,000 neutropenic days for TECs, 13.7 for PICCs, and 10.7 for TICs. After adjustment, there was no statistically significant association between CVAD type and BSI: PICC incident rate ratio [IRR] = 1.00 (95% confidence interval [CI], 0.75-1.32) and TIC IRR = 0.83 (95% CI, 0.49-1.41) compared to TEC. When MBI and non-MBI were examined separately, results were similar. CONCLUSIONS: In this large, multicenter cohort of pediatric AML patients, we found no difference in the rate of BSI during neutropenia by CVAD type. This may be due to a risk-profile for BSI that is unique to AML patients.

Malnutrition from anorexia nervosa triggers severe complications of hereditary spherocytosis in an adolescent girl: A case report.

Hemolytic crises and aplastic crises in hereditary spherocytosis (HS) are most commonly triggered by viral infections. We present the case of an adolescent girl with HS who developed unexpected and life-threatening complications of her inherited hemolytic anemia as a consequence of anorexia nervosa and severe malnutrition.

Characterization of the Serpentine Adeno-Associated Virus (SAAV) Capsid Structure: Receptor Interactions and Antigenicity.

Adeno-associated viruses (AAVs) are being developed as clinical gene therapy vectors. One issue undermining their broad use in the clinical setting is the high prevalence of circulating antibodies in the general population capable of neutralizing AAV vectors. Hence, there is a need for AAV vectors that can evade the preexisting immune response. One possible source of human naive vectors are AAVs that do not disseminate in the primate population, and one such example is serpentine AAV (SAAV). This study characterizes the structural and biophysical properties of the SAAV capsid and its receptor interactions and antigenicity. Single particle cryo-electron microscopy (cryo-EM) and thermal stability studies were conducted to characterize the SAAV capsid structure at pH 7.4, 6.0, 5.5, and 4.0, conditions experienced during cellular trafficking. Cell binding assays using Chinese hamster ovary (CHO) cell lines identified terminal sialic acid as the primary attachment receptor for SAAV similar to AAV1, 4, 5, and 6. The binding site of sialic acid to the SAAV capsid was mapped near the 2-fold axis toward the 2/5-fold wall, in a different location than AAV1, 4, 5, and 6. Towards determining the SAAV capsid antigenicity native immunodot blots showed that SAAV evades AAV serotype-specific mouse monoclonal antibodies. However, despite its reptilian origin, it was recognized by ~25% of 50 human sera tested, likely due to the presence of cross-reactive antibodies. These findings will inform future gene delivery applications using SAAV-based vectors and further aid the structural characterization and annotation of the repertoire of available AAV capsids. IMPORTANCE AAVs are widely studied therapeutic gene delivery vectors. However, preexisting antibodies and their detrimental effect on therapeutic efficacy are a primary challenge encountered during clinical trials. In order to circumvent preexisting neutralizing antibodies targeting mammalian AAV capsids, serpentine AAV (SAAV) was evaluated as a potential alternative to existing mammalian therapeutic vectors. The SAAV capsid was found to be thermostable at a wide range of environmental pH conditions, and its structure showed conservation of the core capsid topology but displays high structural variability on the surface. At the same time, it binds to a common receptor, sialic acid, that is also utilized by other AAVs already being utilized in gene therapy trials. Contrary to the initial hypothesis, SAAV capsids were recognized by one in four human sera tested, pointing to conserved amino acids around the 5-fold region as epitopes for cross-reacting antibodies.

Medical Outcomes, Quality of Life, and Family Perceptions for Outpatient vs Inpatient Neutropenia Management After Chemotherapy for Pediatric Acute Myeloid Leukemia.

Importance: Pediatric acute myeloid leukemia (AML) requires multiple courses of intensive chemotherapy that result in neutropenia, with significant risk for infectious complications. Supportive care guidelines recommend hospitalization until neutrophil recovery. However, there are little data to support inpatient over outpatient management. Objective: To evaluate outpatient vs inpatient neutropenia management for pediatric AML. Design, Setting, and Participants: This cohort study used qualitative and quantitative methods to compare medical outcomes, patient health-related quality of life (HRQOL), and patient and family perceptions between outpatient and inpatient neutropenia management. The study included patients from 17 US pediatric hospitals with frontline chemotherapy start dates ranging from January 2011 to July 2019, although the specific date ranges differed for the individual analyses by design and relative timing. Data were analyzed from August 2019 to February 2020. Exposures: Discharge to outpatient vs inpatient neutropenia management. Main Outcomes and Measures: The primary outcomes of interest were course-specific bacteremia incidence, times to next course, and patient HRQOL. Course-specific mortality was a secondary medical outcome. Results: Primary quantitative analyses included 554 patients (272 [49.1%] girls and 282 [50.9%] boys; mean [SD] age, 8.2 [6.1] years). Bacteremia incidence was not significantly different during outpatient vs inpatient management (67 courses [23.8%] vs 265 courses [29.0%]; adjusted rate ratio, 0.73; 95% CI, 0.56 to 1.06; P = .08). Outpatient management was not associated with delays to the next course compared with inpatient management (mean [SD] 30.7 [12.2] days vs 32.8 [9.7] days; adjusted mean difference, -2.2; 95% CI, -4.1 to -0.2, P = .03). Mortality during intensification II was higher for patients who received outpatient management compared with those who received inpatient management (3 patients [5.4%] vs 1 patient [0.5%]; P = .03), but comparable with inpatient management at other courses (eg, 0 patients vs 5 patients [1.3%] during induction I; P = .59). Among 97 patients evaluated for HRQOL, outcomes did not differ between outpatient and inpatient management (mean [SD] Pediatric Quality of Life Inventory total score, 70.1 [18.9] vs 68.7 [19.4]; adjusted mean difference, -2.8; 95% CI, -11.2 to 5.6). A total of 86 respondents (20 [23.3%] in outpatient management, 66 [76.7%] in inpatient management) completed qualitative interviews. Independent of management strategy received, 74 respondents (86.0%) expressed satisfaction with their experience. Concerns for hospital-associated infections among caregivers (6 of 7 caregiver respondents [85.7%] who were dissatisfied with inpatient management) and family separation (2 of 2 patient respondents [100%] who were dissatisfied with inpatient management) drove dissatisfaction with inpatient management. Stress of caring for a neutropenic child at home (3 of 3 respondents [100%] who were dissatisfied with outpatient management) drove dissatisfaction with outpatient management. Conclusions and Relevance: This cohort study found that outpatient neutropenia management was not associated with higher bacteremia incidence, treatment delays, or worse HRQOL compared with inpatient neutropenia management among pediatric patients with AML. While outpatient management may be safe for many patients, course-specific mortality differences suggest that outpatient management in intensification II should be approached with caution. Patient and family experiences varied, suggesting that outpatient management may be preferred by some but may not be feasible for all families. Further studies to refine and standardize safe outpatient management practices are warranted.

Structural Study of Aavrh.10 Receptor and Antibody Interactions.

Recombinant adeno-associated virus (rAAV) vectors are one of the leading tools for the delivery of therapeutic genes in human gene therapy applications. For a successful transfer of their payload, the AAV vectors have to circumvent potential preexisting neutralizing host antibodies and bind to the receptors of the target cells. Both of these aspects have not been structurally analyzed for AAVrh.10. Here, cryo-electron microscopy and three-dimensional image reconstruction were used to map the binding site of sulfated N-acetyllactosamine (LacNAc; previously shown to bind AAVrh.10) and a series of four monoclonal antibodies (MAbs). LacNAc was found to bind to a pocket located on the side of the 3-fold capsid protrusion that is mostly conserved to AAV9 and equivalent to its galactose-binding site. As a result, AAVrh.10 was also shown to be able to bind to cell surface glycans with terminal galactose. For the antigenic characterization, it was observed that several anti-AAV8 MAbs cross-react with AAVrh.10. The binding sites of these antibodies were mapped to the 3-fold capsid protrusions. Based on these observations, the AAVrh.10 capsid surface was engineered to create variant capsids that escape these antibodies while maintaining infectivity. IMPORTANCE Gene therapy vectors based on adeno-associated virus rhesus isolate 10 (AAVrh.10) have been used in several clinical trials to treat monogenetic diseases. However, compared to other AAV serotypes little is known about receptor binding and antigenicity of the AAVrh.10 capsid. Particularly, preexisting neutralizing antibodies against capsids are an important challenge that can hamper treatment efficiency. This study addresses both topics and identifies critical regions of the AAVrh.10 capsid for receptor and antibody binding. The insights gained were utilized to generate AAVrh.10 variants capable of evading known neutralizing antibodies. The findings of this study could further aid the utilization of AAVrh.10 vectors in clinical trials and help the approval of the subsequent biologics.

Diagnostic and Treatment Challenges for Acquired Hemophilia A in Pediatrics: Report of 2 Cases.

Acquired hemophilia A (AHA) occurs rarely in children. We report 2 cases of adolescent females with AHA. The first case underwent bone marrow aspiration/biopsy during workup, which was complicated by bleeding. Bleeding resolved after initiation of therapy with cyclophosphamide and glucocorticoid, but despite the addition of rituximab, she did not achieve complete remission until treatment with intravenous immunoglobulin. In the second case, we observed that a mixing study without incubation will not detect an acquired factor VIII inhibitor, but further workup based on suspicion for AHA led to the correct diagnosis. Both had significant medication toxicity which required treatment modification.

Characterization of AAV-Specific Affinity Ligands: Consequences for Vector Purification and Development Strategies.

Affinity-based purification of adeno-associated virus (AAV) vectors has replaced density-based methods for vectors used in clinical settings. This method utilizes camelid single-domain antibodies recognizing AAV capsids. These include AVB Sepharose (AVB) and POROS CaptureSelect affinity ligand for AAV8 (CSAL8) and AAV9 (CSAL9). In this study, we utilized cryo-electron microscopy and 3D image reconstruction to map the binding sites of these affinity ligands on the capsids of several AAV serotypes, including AAV1, AAV2, AAV5, AAV8, and AAV9, representing the range of sequence and structure diversity among AAVs. The AAV-ligand complex structures showed that AVB and CSAL9 bound to the 5-fold capsid region, although in different orientations, and CSAL8 bound to the side of the 3-fold protrusion. The AAV contact residues required for ligand binding, and thus AAV purification, and the ability of the ligands to neutralize infection were analyzed. The data show that only a few residues within the epitopes served to block affinity ligand binding. Neutralization was observed for AAV1 and AAV5 with AVB, for AAV1 with CSAL8, and for AAV9 with CSAL9, associated with regions that overlap with epitopes for neutralizing monoclonal antibodies against these capsids. This information is critical and could be generally applicable in the development of novel AAV vectors amenable to affinity column purification.

Structural Characterization of Cuta- and Tusavirus: Insight into Protoparvoviruses Capsid Morphology.

Several members of the Protoparvovirus genus, capable of infecting humans, have been recently discovered, including cutavirus (CuV) and tusavirus (TuV). To begin the characterization of these viruses, we have used cryo-electron microscopy and image reconstruction to determine their capsid structures to ~2.9 Å resolution, and glycan array and cell-based assays to identify glycans utilized for cellular entry. Structural comparisons show that the CuV and TuV capsids share common features with other parvoviruses, including an eight-stranded anti-parallel ß-barrel, depressions at the icosahedral 2-fold and surrounding the 5-fold axes, and a channel at the 5-fold axes. However, the viruses exhibit significant topological differences in their viral protein surface loops. These result in three separated 3-fold protrusions, similar to the bufaviruses also infecting humans, suggesting a host-driven structure evolution. The surface loops contain residues involved in receptor binding, cellular trafficking, and antigenic reactivity in other parvoviruses. In addition, terminal sialic acid was identified as the glycan potentially utilized by both CuV and TuV for cellular entry, with TuV showing additional recognition of poly-sialic acid and sialylated Lewis X (sLeXLeXLeX) motifs reported to be upregulated in neurotropic and cancer cells, respectively. These structures provide a platform for annotating the cellular interactions of these human pathogens.

Mouse models of neutropenia reveal progenitor-stage-specific defects.

Advances in genetics and sequencing have identified a plethora of disease-associated and disease-causing genetic alterations. To determine causality between genetics and disease, accurate models for molecular dissection are required; however, the rapid expansion of transcriptional populations identified through single-cell analyses presents a major challenge for accurate comparisons between mutant and wild-type cells. Here we generate mouse models of human severe congenital neutropenia (SCN) using patient-derived mutations in the GFI1 transcription factor. To determine the effects of SCN mutations, we generated single-cell references for granulopoietic genomic states with linked epitopes1, aligned mutant cells to their wild-type equivalents and identified differentially expressed genes and epigenetic loci. We find that GFI1-target genes are altered sequentially, as cells go through successive states of differentiation. These insights facilitated the genetic rescue of granulocytic specification but not post-commitment defects in innate immune effector function, and underscore the importance of evaluating the effects of mutations and therapy within each relevant cell state.

Adeno-Associated Virus VP1u Exhibits Protease Activity.

Adeno-associated viruses (AAVs) are being developed for gene delivery applications, with more than 100 ongoing clinical trials aimed at the treatment of monogenic diseases. In this study, the unique N-terminus of AAV capsid viral protein 1 (VP1u), containing a canonical group XIII PLA2 enzyme domain, was observed to also exhibit proteolytic activity. This protease activity can target casein and gelatin, two standard substrates used for testing protease function but does not self-cleave in the context of the capsid or target globular proteins, for example, bovine serum albumin (BSA). However, heated BSA is susceptible to VP1u-mediated cleavage, suggesting that disordered proteins are substrates for this protease function. The protease activity is partially inhibited by divalent cation chelators ethylenediaminetetraacetic acid (EDTA) and ethylene-bis(oxyethylenenitrilo)tetraacetic acid (EGTA), and human alpha-2-macroglobulin (A2M), a non-specific protease inhibitor. Interestingly, both the bovine pancreatic (group VIIA) and bee venom (group III) PLA2 enzymes also exhibit protease function against casein. This indicates that PLA2 groups, including VP1u, have a protease function. Amino acid substitution of the PLA2 catalytic motif (76HD/AN) in the AAV2 VP1u resulted in attenuation of protease activity, suggesting that the protease and PLA2 active sites are related. However, the amino acid substitution of histidine H38, which is not involved in PLA2 function, to alanine, also affects protease activity, suggesting that the active site/mechanism of the PLA2 and protease function are not identical.

Hematologic Manifestations of Nutritional Deficiencies: Early Recognition is Essential to Prevent Serious Complications.

Nutritional deficiencies, including deficiencies of vitamin B12, copper, and vitamin C, may result in cytopenias and hematologic symptoms. Early recognition of these deficiencies is imperative for prompt treatment and improvement in hematologic and other manifestations. We describe 5 cases which illustrate the hematologic manifestations of nutritional deficiencies and challenges to initial diagnosis and management. Supplementation of the deficient vitamin or micronutrient in all of these cases resulted in rapid resolution of cytopenias, hemorrhage, and other associated hematologic symptoms. We also review other nutritional deficiencies that manifest with hematologic symptoms and compile recommendations on treatment and expected time to response.

Transfusion practices and complications in thalassemia.

BACKGROUND: The severe forms of thalassemia are the most common inherited anemias managed with regular blood transfusion therapy. Transfusion policies and complications are critical to quality of life and survival, but there is a lack of standardized care. STUDY DESIGN AND METHODS: A survey of 58 items was completed in 2016 by 11 centers in California, Washington, Oregon, Nevada, and Arizona providing long-term care for thalassemia. The questionnaire addressed demographic information, transfusion practices and complications, and educational needs. RESULTS: The centers followed 717 patients with ß-thalassemia (314, 43.8%) or α-thalassemia (394, 55%). One-third (34.7%) of patients were transfusion-dependent. Indications and goals of transfusion therapy differed between centers. Prestorage leukoreduction was universal, while routine irradiation of units was limited to one site. Red blood cell antigen phenotype was determined before the first transfusion and patients received Rh/Kell-matched units. However, more than half of the transfused patients had received blood at multiple hospitals within or outside the United States. Alloantibodies were seen in 16.9% of transfused group, but management of such patients was variable. Unusual or emerging transfusion-transmitted pathogens were not observed. Multiple educational needs were recognized, with iron overload as the biggest challenge; the approach to iron chelation varied within the group. CONCLUSION: This study identified many patients not included in earlier surveys limited to major national centers, suggesting that the thalassemia population in the United States is vastly underestimated. Lack of evidence-based guidelines is a barrier to optimal care, which should be addressed through regional consortia of thalassemia centers.

Induction of antiinflammatory purinergic signaling in activated human iNKT cells.

Invariant natural killer T (iNKT) cells are activated at sites of local tissue injury, or globally during vaso-occlusive episodes of sickle cell disease (SCD). Tissue damage stimulates production of CD1d-restricted lipid antigens that activate iNKT cells to produce Th1- and Th2-type cytokines. Here, we show that circulating iNKT cells in SCD patients express elevated levels of the ectonucleoside triphosphate diphosphosphohydrolase, CD39, as well the adenosine A2A receptor (A2AR). We also investigated the effects of stimulating cultured human iNKT cells on the expression of genes involved in the regulation of purinergic signaling. iNKT cell stimulation caused induction of ADORA2A, P2RX7, CD38, CD39, ENPP1, CD73, PANX1, and ENT1. Transcription of ADA, which degrades adenosine, was reduced. Induction of CD39 mRNA was associated with increased ecto-ATPase activity on iNKT cells that was blocked by POM1. Exposure of iNKT cells to A2AR agonists during stimulation reduced production of IFN-γ and enhanced production of IL-13 and CD39. Based on these findings, we define "purinergic Th2-type cytokine bias" as an antiinflammatory purinergic response to iNKT cell stimulation resulting from changes in the transcription of several genes involved in purine release, extracellular metabolism, and signaling.

Thermal Stability as a Determinant of AAV Serotype Identity.

Currently, there are over 150 ongoing clinical trials utilizing adeno-associated viruses (AAVs) to target various genetic diseases, including hemophilia (AAV2 and AAV8), congenital heart failure (AAV1 and AAV6), cystic fibrosis (AAV2), rheumatoid arthritis (AAV2), and Batten disease (AAVrh.10). Prior to patient administration, AAV vectors must have their serotype, concentration, purity, and stability confirmed. Here, we report the application of differential scanning fluorimetry (DSF) as a good manufacturing practice (GMP) capable of determining the melting temperature (Tm) for AAV serotype identification. This is a simple, rapid, cost effective, and robust method utilizing small amounts of purified AAV capsids (∼25 µL of ∼1011 particles). AAV1-9 and AAVrh.10 exhibit specific Tms in buffer formulations commonly used in clinical trials. Notably, AAV2 and AAV3, which are the least stable, have varied Tms, whereas AAV5, the most stable, has a narrow Tm range in the different buffers, respectively. Vector stability was dictated by VP3 only, specifically, the ratio of basic/acidic amino acids, and was independent of VP1 and VP2 content or the genome packaged. Furthermore, stability of recombinant AAVs differing by a single basic or acidic amino acid residue are distinguishable. Hence, AAV DSF profiles can serve as a robust method for serotype identification of clinical vectors.

Cost and safety of pediatric intensive care physician-placed broviac catheters.

OBJECTIVE: To compare the cost and safety of placement of Broviac catheters in children by pediatric intensivists in a sedation suite versus placement by pediatric surgeons in the operating room. DESIGN: Single-center retrospective analysis. SETTING: Pediatric sedation suite and operating rooms in a tertiary care children's hospital. PATIENTS: All pediatric patients with Broviac catheters placed (n = 253) at this institution over a 3-year period from 2007 to 2009. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We reviewed the charts of all pediatric patients with Broviac catheters placed, either by intensivists or surgeons, and compared cost and outcomes. Procedure safety was assessed and categorized into immediate, short-term (within 2 wk of procedure), and long-term outcomes. Anesthetic safety and billing data for the procedure were also collected. Among similar patient populations, immediate complications, such as pneumothorax, procedure failure (p > 0.999), and anesthetic complications (p = 0.60), were not significantly different. Short-term outcomes, including infection (p = 0.27) and catheter malfunction (p > 0.999), were not different. Long-term outcomes, including mean indwelling catheter days (p = 0.60) and removal due to catheter infection (p = 0.09), were not different between the groups. Overall cost of the procedure was significantly different: $7,031 (± $784) when performed by surgeons and $3,565 (± $311) when performed by intensivists (p < 0.001). CONCLUSIONS: Pediatric critical care physicians can place Broviac catheters as safely as pediatric surgeons and at a lower cost in a defined patient population.

NF-κB is activated in CD4+ iNKT cells by sickle cell disease and mediates rapid induction of adenosine A2A receptors.

Reperfusion injury following tissue ischemia occurs as a consequence of vaso-occlusion that is initiated by activation of invariant natural killer T (iNKT) cells. Sickle cell disease (SDC) results in widely disseminated microvascular ischemia and reperfusion injury as a result of vaso-occlusion by rigid and adhesive sickle red blood cells. In mice, iNKT cell activation requires NF-κB signaling and can be inhibited by the activation of anti-inflammatory adenosine A2A receptors (A2ARs). Human iNKT cells are divided into subsets of CD4+ and CD4- cells. In this study we found that human CD4+ iNKT cells, but not CD4- cells undergo rapid NF-κB activation (phosphorylation of NF-κB on p65) and induction of A2ARs (detected with a monoclonal antibody 7F6-G5-A2) during SCD painful vaso-occlusive crises. These findings indicate that SCD primarily activates the CD4+ subset of iNKT cells. Activation of NF-κB and induction of A2ARs is concordant, i.e. only CD4+ iNKT cells with activated NF-κB expressed high levels of A2ARs. iNKT cells that are not activated during pVOC express low levels of A2AR immunoreactivity. These finding suggest that A2AR transcription may be induced in CD4+ iNKT cells as a result of NF-κB activation in SCD. In order to test this hypothesis further we examined cultured human iNKT cells. In cultured cells, blockade of NF-κB with Bay 11-7082 or IKK inhibitor VII prevented rapid induction of A2AR mRNA and protein upon iNKT activation. In conclusion, NF-κB-mediated induction of A2ARs in iNKT cells may serve as a counter-regulatory mechanism to limit the extent and duration of inflammatory immune responses. As activated iNKT cells express high levels of A2ARs following their activation, they may become highly sensitive to inhibition by A2AR agonists.

Coming of age: steroid hormones of wild immature baboons (Papio cynocephalus).

Large gaps exist in our knowledge about common patterns and variability in the endocrinology of immature nonhuman primates, and even normal hormonal profiles during that life stage are lacking for wild populations. In the present study we present steroid profiles for a wild population of baboons (Papio cynocephalus) from infancy through reproductive maturation, obtained by noninvasive fecal analyses. Fecal concentrations of glucocorticoid (fGC) and testosterone (fT) metabolites for males, and of fGC, estrogen (fE), and progestin (fP) metabolites for females were measured by radioimmunoassay (RIA). In males, infancy was characterized by high and declining levels of fGC and fT, whereas steroid concentrations were low during the juvenile years. During the months immediately prior to testicular enlargement, fT (but not fGC) concentration tended to increase. Males that matured early consistently had higher fT and fGC concentrations than those that matured late, but not significantly so at any age. Individual differences in fT concentrations were stable across ages, and average individual fT and fGC concentrations were positively correlated. For females, high and declining levels of fE characterized infancy, and values increased again after 3.5 years of age, as some females reached menarche by that age. Both fP and fGC were relatively low and constant throughout infancy and the juvenile period. During the months immediately prior to menarche, fGC concentration significantly decreased, while no changes were observed for fE levels. fP exhibited a complicated pattern of decrease that was subsequently followed by a more modest and nonsignificant increase as menarche approached. Early- (EM) and late-maturing (LM) females differed only in fP concentration; the higher fP concentrations in EM females reached significance at 4-4.5 years of age. Maternal rank at offspring conception did not predict concentrations of any hormone for either sex. Our results demonstrate the presence of individual endocrine variability, which could have important consequences for the timing of sexual maturation and subsequently for individual reproductive success. Further evaluation of the factors that affect hormone concentrations during the juvenile and adolescent periods should lead to a better understanding of mechanisms of life-history variability.