Targeted delivery of a PD-1-blocking scFv by CAR-T cells enhances anti-tumor efficacy in vivo.

The efficacy of chimeric antigen receptor (CAR) T cell therapy against poorly responding tumors can be enhanced by administering the cells in combination with immune checkpoint blockade inhibitors. Alternatively, the CAR construct has been engineered to coexpress factors that boost CAR-T cell function in the tumor microenvironment. We modified CAR-T cells to secrete PD-1-blocking single-chain variable fragments (scFv). These scFv-secreting CAR-T cells acted in both a paracrine and autocrine manner to improve the anti-tumor activity of CAR-T cells and bystander tumor-specific T cells in clinically relevant syngeneic and xenogeneic mouse models of PD-L1+ hematologic and solid tumors. The efficacy was similar to or better than that achieved by combination therapy with CAR-T cells and a checkpoint inhibitor. This approach may improve safety, as the secreted scFvs remained localized to the tumor, protecting CAR-T cells from PD-1 inhibition, which could potentially avoid toxicities associated with systemic checkpoint inhibition.

Toxicity and management in CAR T-cell therapy.

T cells can be genetically modified to target tumors through the expression of a chimeric antigen receptor (CAR). Most notably, CAR T cells have demonstrated clinical efficacy in hematologic malignancies with more modest responses when targeting solid tumors. However, CAR T cells also have the capacity to elicit expected and unexpected toxicities including: cytokine release syndrome, neurologic toxicity, "on target/off tumor" recognition, and anaphylaxis. Theoretical toxicities including clonal expansion secondary to insertional oncogenesis, graft versus host disease, and off-target antigen recognition have not been clinically evident. Abrogating toxicity has become a critical step in the successful application of this emerging technology. To this end, we review the reported and theoretical toxicities of CAR T cells and their management.

Driving CAR T-cells forward.

The engineered expression of chimeric antigen receptors (CARs) on the surface of T cells enables the redirection of T-cell specificity. Early clinical trials using CAR T cells for the treatment of patients with cancer showed modest results, but the impressive outcomes of several trials of CD19-targeted CAR T cells in the treatment of patients with B-cell malignancies have generated an increased enthusiasm for this approach. Important lessons have been derived from clinical trials of CD19-specific CAR T cells, and ongoing clinical trials are testing CAR designs directed at novel targets involved in haematological and solid malignancies. In this Review, we discuss these trials and present strategies that can increase the antitumour efficacy and safety of CAR T-cell therapy. Given the fast-moving nature of this field, we only discuss studies with direct translational application currently or soon-to-be tested in the clinical setting.

Overcoming Antigen Escape with CAR T-cell Therapy.

Sotillo and colleagues describe the molecular events associated with apparent loss of target antigen expression following CAR T-cell therapy. We propose that broader immune activation is required to prevent outgrowth of tumor antigen escape variants following targeted therapies.

Phase I Study of Vorinostat as a Radiation Sensitizer with 131I-Metaiodobenzylguanidine (131I-MIBG) for Patients with Relapsed or Refractory Neuroblastoma.

PURPOSE: (131)I-metaiodobenzylguanidine (MIBG) is a radiopharmaceutical with activity in neuroblastoma. Vorinostat is a histone deacetylase inhibitor that has radiosensitizing properties. The goal of this phase I study was to determine the MTDs of vorinostat and MIBG in combination. EXPERIMENTAL DESIGN: Patients ≤ 30 years with relapsed/refractory MIBG-avid neuroblastoma were eligible. Patients received oral vorinostat (dose levels 180 and 230 mg/m(2)) daily days 1 to 14. MIBG (dose levels 8, 12, 15, and 18 mCi/kg) was given on day 3 and peripheral blood stem cells on day 17. Alternating dose escalation of vorinostat and MIBG was performed using a 3+3 design. RESULTS: Twenty-seven patients enrolled to six dose levels, with 23 evaluable for dose escalation. No dose-limiting toxicities (DLT) were seen in the first three dose levels. At dose level 4 (15 mCi/kg MIBG/230 mg/m(2) vorinostat), 1 of 6 patients had DLT with grade 4 hypokalemia. At dose level 5 (18 mCi/kg MIBG/230 mg/m(2) vorinostat), 2 patients had dose-limiting bleeding (one grade 3 and one grade 5). At dose level 5a (18 mCi/kg MIBG/180 mg/m(2) vorinostat), 0 of 6 patients had DLT. The most common toxicities were neutropenia and thrombocytopenia. The response rate was 12% across all dose levels and 17% at dose level 5a. Histone acetylation increased from baseline in peripheral blood mononuclear cells collected on days 3 and 12 to 14. CONCLUSIONS: Vorinostat at 180 mg/m(2)/dose is tolerable with 18 mCi/kg MIBG. A phase II trial comparing this regimen to single-agent MIBG is ongoing.

131I-metaiodobenzylguanidine with intensive chemotherapy and autologous stem cell transplantation for high-risk neuroblastoma. A new approaches to neuroblastoma therapy (NANT) phase II study.

(131)I-Metaiodobenzylguanidine ((131)I-MIBG) has been used as a single agent or in combination with chemotherapy for the treatment of high-risk neuroblastoma. The activity and toxicity of (131)I-MIBG when combined with carboplatin, etoposide, and melphalan (CEM) and autologous stem cell transplantation (SCT) are now investigated in a phase II multicenter study. Fifty patients with MIBG-avid disease were enrolled into 2 cohorts, stratified by response to induction therapy. The primary study endpoint was response of patients with refractory (n = 27) or progressive disease (n = 15). A second cohort of patients (n = 8) with a partial response (PR) to induction therapy was included to obtain preliminary response data. (131)I-MIBG was administered on day -21 to all patients, with CEM given days -7 to -4, and SCT given on day 0. (131)I-MIBG dosing was determined by pre-therapy glomerular filtration rate (GFR), with 8 mCi/kg given if GFR was 60 to 99 mL/minute/1.73 m(2) (n = 13) and 12 mCi/kg if GFR ≥ 100 mL/minute/1.73 m(2) (n = 37). External beam radiotherapy was delivered to the primary and metastatic sites, beginning approximately 6 weeks after SCT. Responses (complete response + PR) were seen in 4 of 41 (10%) evaluable patients with primary refractory or progressive disease. At 3 years after SCT, the event-free survival (EFS) was 20% ± 7%, with overall survival (OS) 62% ± 8% for this cohort of patients. Responses were noted in 3 of 8 (38%) of patients with a PR to induction, with 3-year EFS 38% ± 17% and OS 75% ± 15%. No statistically significant difference was found comparing EFS or OS based upon pre-therapy GFR or disease cohort. Six of 50 patients had nonhematologic dose-limiting toxicity (DLT); 1 of 13 in the low GFR and 5 of 37 in the normal GFR cohorts. Hepatic sinusoidal obstructive syndrome (SOS) was seen in 6 patients (12%), with 5 events defined as dose-limiting SOS. The median times to neutrophil and platelet engraftment were 10 and 15 days, respectively. Patients received a median 163 cGy (61 to 846 cGy) with (131)I-MIBG administration, with 2 of 3 patients receiving >500 cGy experiencing DLT. The addition of (131)I-MIBG to a myeloablative CEM regimen is tolerable and active therapy for patients with high-risk neuroblastoma.

Abnormal development of thalamic microstructure in premature neonates with congenital heart disease.

Preterm birth is associated with alteration in corticothalamic development, which underlies poor neurodevelopmental outcomes. Our hypothesis was that preterm neonates with CHD would demonstrate abnormal thalamic microstructure when compared to critically ill neonates without CHD. A secondary aim was to identify any association between thalamic microstructural abnormalities and perioperative clinical variables. We compared thalamic DTI measurements in 21 preterm neonates with CHD to two cohorts of neonates without CHD: 28 term and 27 preterm neonates, identified from the same neonatal intensive care unit. Comparison was made with three other selected white matter regions using ROI manual-based measurements. Correlation was made with post-conceptional age and perioperative clinical variables. In preterm neonates with CHD, there were age-related differences in thalamic diffusivity (axial and radial) compared to the preterm and term non-CHD group, in contrast to no differences in anisotropy. Contrary to our hypothesis, abnormal thalamic and optic radiation microstructure was most strongly associated with an elevated first arterial blood gas pO2 and elevated preoperative arterial blood gas pH (p < 0.05). Age-related thalamic microstructural abnormalities were observed in preterm neonates with CHD. Perinatal hyperoxemia and increased perioperative serum pH were associated with abnormal thalamic microstructure in preterm neonates with CHD. This study emphasizes the vulnerability of thalamocortical development in the preterm neonate with CHD.

Time to disease progression in children with relapsed or refractory neuroblastoma treated with ABT-751: a report from the Children's Oncology Group (ANBL0621).

BACKGROUND: ABT-751, an orally bioavailable sulfonamide binds the colchicine site of beta-tubulin and inhibits microtubule polymerization. Prior phase I studies established the recommended dose in children with solid tumors as 200 mg/m(2) PO daily × 7 days every 21 days and subjects with neuroblastoma experienced prolonged stable disease. We conducted a phase 2 study (NCT00436852) in children and adolescents with progressive neuroblastoma to determine if ABT-751 prolonged the time to progression (TTP) compared to a hypothesized standard based on a historical control population. PROCEDURE: Children and adolescents (n = 91) with a median (range) age 7.7 (2.3-21.5) years and progressive neuroblastoma were enrolled and stratified by disease status into disease measureable by CT/MRI (n = 47) or disease assessable by (123) I-metaiodobenzylguanine scintigraphy (MIBG, n = 44). Response was evaluated using RECIST for measureable disease and the Curie score for MIBG-avid disease. RESULTS: ABT-751 was well tolerated. The objective response rate was 7%. The median TTP was 42 days (95% CI: 36, 56) in the measureable disease stratum and 45 days (95% CI: 42, 85) in the MIBG-avid disease stratum. TTP was similar to the historical control group (n = 136, median TTP 42 days). For the combined strata (n = 91), 1-year progression free survival (PFS) was 13 ± 4% and overall survival (OS) was 48 ± 5%. CONCLUSIONS: The low objective response rate and failure to prolong TTP indicate that ABT-751 is not sufficiently active to warrant further development for neuroblastoma. However, this trial demonstrates the utility of TTP as the primary endpoint in phase 2 trials in children and adolescents with neuroblastoma.

Phase I trial of fenretinide delivered orally in a novel organized lipid complex in patients with relapsed/refractory neuroblastoma: a report from the New Approaches to Neuroblastoma Therapy (NANT) consortium.

BACKGROUND: A phase I study was conducted to determine the maximum-tolerated dose, dose-limiting toxicities (DLTs), and pharmacokinetics of fenretinide (4-HPR) delivered in an oral powderized lipid complex (LXS) in patients with relapsed/refractory neuroblastoma. PROCEDURE: 4-HPR/LXS powder (352-2,210 mg/m(2) /day) was administered on Days 0-6, in 21-day courses, by standard 3 + 3 design. RESULTS: Thirty-two patients (median age = 8 years, range 3-27 years) enrolled with 30 evaluable for dose escalation. Prior therapies included stem cell transplantation/support (n = 26), 13-cis-retinoic acid (n = 22), (125/131) I-MIBG (n = 13), and anti-GD2 antibody (n = 6). 170+ courses were delivered. Course 1 DLTs were a Grade 3 (n = 1) alkaline phosphatase at 352 mg/m(2) /day. Other major toxicities were Grade 4 (n = 1) alkaline phosphatases on Courses 5 and 6 at 774 mg/m(2) /day, and Grade 3 (n = 1) ALT/AST elevation on Course 2 at 1,700 mg/m(2) /day. Of 29 response-evaluable patients, six had stable disease (SD) (4-26 courses); four with marrow- or bone disease-only had complete responses (CR) (10-46 courses). 4-HPR plasma levels were several folds higher (P < 0.05) than previously reported using capsular fenretinide. The Day 6 mean peak 4-HPR plasma level at 1,700 mg/m(2) /day was 21 µM. An MTD was not reached. CONCLUSIONS: 4-HPR/LXS oral powder obtained higher plasma levels, with minimal toxicity and evidence of anti-tumor activity, than a previous capsule formulation. A recommended phase II schedule of 4-HPR/LXS powder is 1,500 mg/m(2) /day, TID, on Days 0-6, of a 21-day course.

Dose escalation study of no-carrier-added 131I-metaiodobenzylguanidine for relapsed or refractory neuroblastoma: new approaches to neuroblastoma therapy consortium trial.

UNLABELLED: (131)I-metaiodobenzylguanidine (MIBG) is specifically taken up in neuroblastoma, with a response rate of 20%-37% in relapsed disease. Nonradioactive carrier MIBG molecules inhibit uptake of (131)I-MIBG, theoretically resulting in less tumor radiation and increased risk of cardiovascular toxicity. Our aim was to establish the maximum tolerated dose of no-carrier-added (NCA) (131)I-MIBG, with secondary aims of assessing tumor and organ dosimetry and overall response. METHODS: Eligible patients were 1-30 y old with resistant neuroblastoma, (131)I-MIBG uptake, and cryopreserved hematopoietic stem cells. A diagnostic dose of NCA (131)I-MIBG was followed by 3 dosimetry scans to assess radiation dose to critical organs and soft-tissue tumors. The treatment dose of NCA (131)I-MIBG (specific activity, 165 MBq/µg) was adjusted as necessary on the basis of critical organ tolerance limits. Autologous hematopoietic stem cells were infused 14 d after therapy to abrogate prolonged myelosuppression. Response and toxicity were evaluated on day 60. The NCA (131)I-MIBG was escalated from 444 to 777 MBq/kg (12-21 mCi/kg) using a 3 + 3 design. Dose-limiting toxicity (DLT) was failure to reconstitute neutrophils to greater than 500/µL within 28 d or platelets to greater than 20,000/µL within 56 d, or grade 3 or 4 nonhematologic toxicity by Common Terminology Criteria for Adverse Events (version 3.0) except for predefined exclusions. RESULTS: Three patients each were evaluable at 444, 555, and 666 MBq/kg without DLT. The dose of 777 MBq/kg dose was not feasible because of organ dosimetry limits; however, 3 assigned patients were evaluable for a received dose of 666 MBq/kg, providing a total of 6 patients evaluable for toxicity at 666 MBq/kg without DLT. Mean whole-body radiation was 0.23 mGy/MBq, and mean organ doses were 0.92, 0.82, and 1.2 mGy/MBq of MIBG for the liver, lung, and kidney, respectively. Eight patients had 13 soft-tissue lesions with tumor-absorbed doses of 26-378 Gy. Four of 15 patients had a complete (n = 1) or partial (n = 3) response, 1 had a mixed response, 4 had stable disease, and 6 had progressive disease. CONCLUSION: NCA (131)I-MIBG with autologous peripheral blood stem cell transplantation is feasible at 666 MBq/kg without significant nonhematologic toxicity and with promising activity.

The significance of serial histopathology in a residual mass for outcome of intermediate risk stage 3 neuroblastoma.

BACKGROUND: To describe the serial histopathology of intermediate risk stage 3 neuroblastoma after chemotherapy, and correlate with residual mass at therapy completion and outcome. PROCEDURE: A retrospective review of intermediate risk stage 3 neuroblastoma patients treated 1989-2005 at Children's Hospital Los Angeles according to CCG 3881 or CCG 3961 protocols was performed, with central review of histopathology, radiology, and surgery. RESULTS: Eighteen patients treated per CCG 3881 (n = 9) or CCG 3961 (n = 9), with including 1 (n = 5), 2 (n = 9), ≥ 3 (n = 3), or unknown number (n = 1) of surgical procedures were included. At therapy completion, 10 patients had residual tumor: <10% original size (n = 3), >10% original size (n = 6) (5 MIBG avid; 4 with elevated catecholamines), and CT non-measurable MIBG avid tumor (n = 1). Post-chemotherapy histology showed tumor regression (n = 4); or maturation with (n = 6) or without (n = 2) Schwannian development. Histologic changes correlated with median tumor shrinkage of 80% (regressing tumors) and <25% (maturing tumors). Tumor size increased in one patient with maturing tumor and Schwannian development. Overall survival was 100%. CONCLUSION: Post-chemotherapy histopathology of intermediate risk stage 3 neuroblastoma was characterized by regression or maturation. Persisting residual and maturing tumors were not associated with tumor progression, despite MIBG uptake and/or elevated catecholamines, supporting observation only. Histopathology should be obtained in future studies to confirm these findings, and guide length of chemotherapy.

Delayed diagnosis of injuries in pediatric trauma: the role of radiographic ordering practices.

OBJECTIVES: We sought to describe the use of radiographic studies in pediatric major trauma patients and determine the extent to which a selective, clinically guided use of imaging contributes to delayed diagnosis of injury (DDI). METHODS: We conducted a retrospective chart review of 324 consecutive pediatric major trauma patients at our level 1 trauma center. One radiologist reviewed all imaging. Delayed diagnosis of injury was defined as detection after more than 12 hours. Equivalency testing was performed to compare radiology use in patients with and without DDI. RESULTS: Twenty-six (8%) of 324 patients had 36 DDI; 27 (75%) of 36 were orthopedic injuries. Median time to DDI detection was 20.5 hours (interquartile range, 15-60.5). During initial evaluation, DDI patients had similar numbers of plain radiographs (3.5 vs 3, P = .54) but more computed tomographic (CT) scans (4 vs 3, P = .03) compared with patients without DDI. Sixteen percent of all patients received CT thorax; 55%, CT cervical spine; and 56%, CT abdomen. Only 1 clinically important DDI was detected solely on the basis of a later CT scan (0.3%; 95% confidence interval, 0-1.5). No cervical spine, intrathoracic, or intraabdominal DDI was attributable to failure to obtain a CT during initial evaluation. Patients with DDI had higher injury severity scores, intubation rates, and pediatric intensive care unit admission rates than those without DDI. CONCLUSIONS: Patients with DDI had similar initial plain x-ray evaluations to patients without DDI, despite DDI patients being more severely injured. Delayed diagnosis of injury was not attributable to inadequate CT use. Most DDIs were orthopedic, highlighting the importance of a tertiary survey and a low threshold for skeletal radiographs.

In utero detection of retinoblastoma with fetal magnetic resonance and ultrasound: initial experience.

Purpose Our aim was to evaluate and compare the ability of prenatal ultrasound (US) and fetal magnetic resonance imaging (MRI) to detect retinoblastoma lesions in utero. Methods Fetuses at risk for having bilateral retinoblastoma were enrolled in this prospective study. High-resolution US of the fetal eye was performed at 16 to 18 weeks' gestation, every 4 weeks until 32 weeks, then every 2 weeks until delivery. Fetal MRIs were performed every 8 weeks starting at 16 to 18 weeks of gestation. An exam under anesthesia (EUA) was performed postnatally, the gold standard of this study. Lesions were classified as being elevated or minimally elevated based upon their morphology. Results Of six fetuses suspected or confirmed to be at risk for developing bilateral retinoblastoma, one had tumors on her first postnatal EUA exam. A total of two minimally elevated lesions were seen by the EUA but not detected prenatally by imaging. One elevated lesion (2 mm in height) identified by postnatal EUA was initially identified by prenatal US. Fetal MRI did not detect any lesions. Conclusion Both prenatal US and fetal MRI are limited in the detection of minimally elevated retinoblastoma lesions. Prenatal US appears to be more sensitive than fetal MRI in the detection of elevated retinoblastoma lesions.

Hydrographic magnetic resonance imaging of the fetal eye.

Previous work has shown that fetal hydrographic magnetic resonance imaging (MRI) provided additional information complementary to T2-weighted single-shot fast spin echo (ssFSE) images. The objective of this study was to determine if hydrographic MRI provides better conspicuity of fetal eye structures compared with ssFSE MRI. ssFSE and hydrographic images were retrospectively examined in 82 consecutive fetal studies with normal central nervous system without sensitivity encoding. Relative signal intensity values on ssFSE and hydrographic MRI were obtained for vitreous and sclera. Ratios of the signal intensity of vitreous to the signal intensity of sclera were calculated to determine conspicuity. Similar measurements were obtained in a smaller separate data set (n = 41) using hydrographic imaging with sensitivity encoding techniques. The hydrographic images significantly demonstrated greater conspicuity (ratio of vitreous to sclera) than ssFSE images. This was consistent for both sensitivity encoding and no-sensitivity encoding groups. The difference in conspicuity was on average approximately two times greater in the hydrographic images compared with ssFSE images. Hydrographic MRI of the fetal eye provides on average two times greater conspicuity of fetal eye structures than ssFSE imaging. This enhancement is not affected by gestational age or the use of sensitivity encoding parallel imaging techniques.

Phase II study of oral capsular 4-hydroxyphenylretinamide (4-HPR/fenretinide) in pediatric patients with refractory or recurrent neuroblastoma: a report from the Children's Oncology Group.

PURPOSE: To determine the response rate to oral capsular fenretinide in children with recurrent or biopsy proven refractory high-risk neuroblastoma. EXPERIMENTAL DESIGN: Patients received 7 days of fenretinide: 2,475 mg/m(2)/d divided TID (<18 years) or 1,800 mg/m(2)/d divided BID (≥18 years) every 21 days for a maximum of 30 courses. Patients with stable or responding disease after course 30 could request additional compassionate courses. Best response by course 8 was evaluated in stratum 1 (measurable disease on CT/MRI ± bone marrow and/or MIBG avid sites) and stratum 2 (bone marrow and/or MIBG avid sites only). RESULTS: Sixty-two eligible patients, median age 5 years (range 0.6-19.9), were treated in stratum 1 (n = 38) and stratum 2 (n = 24). One partial response (PR) was seen in stratum 2 (n = 24 evaluable). No responses were seen in stratum 1 (n = 35 evaluable). Prolonged stable disease (SD) was seen in 7 patients in stratum 1 and 6 patients in stratum 2 for 4 to 45+ (median 15) courses. Median time to progression was 40 days (range 17-506) for stratum 1 and 48 days (range 17-892) for stratum 2. Mean 4-HPR steady-state trough plasma concentrations were 7.25 µmol/L (coefficient of variation 40-56%) at day 7 course 1. Toxicities were mild and reversible. CONCLUSIONS: Although neither stratum met protocol criteria for efficacy, 1 PR + 13 prolonged SD occurred in 14/59 (24%) of evaluable patients. Low bioavailability may have limited fenretinide activity. Novel fenretinide formulations with improved bioavailability are currently in pediatric phase I studies.

A phase I study of zoledronic acid and low-dose cyclophosphamide in recurrent/refractory neuroblastoma: a new approaches to neuroblastoma therapy (NANT) study.

BACKGROUND: Zoledronic acid, a bisphosphonate, delays progression of bone metastases in adult malignancies. Bone is a common metastatic site of advanced neuroblastoma. We previously reported efficacy of zoledronic acid in a murine model of neuroblastoma bone invasion prompting this Phase I trial of zoledronic acid with cyclophosphamide in children with neuroblastoma and bone metastases. The primary objective was to determine recommended dosing of zoledronic acid for future trials. PROCEDURE: Escalating doses of intravenous zoledronic acid were given every 28 days with oral metronomic cyclophosphamide (25 mg/m(2)/day). Toxicity, response, zoledronic acid pharmacokinetics, bone turnover markers, serum IL-6, and sIL-6R were evaluated. RESULTS: Twenty-one patients, median age 7.5 (range 0.8-25.6) years were treated with 2 mg/m(2) (n = 4), 3 mg/m(2) (n = 3), or 4 mg/m(2) (n = 14) zoledronic acid. Fourteen patients were evaluable for dose escalation. A median of one (range 1-18) courses was given. Two dose limiting toxicities (grade 3 hypophosphatemia) occurred at 4 mg/m(2) zoledronic acid. Other grades 3-4 toxicities included hypocalcemia (n = 2), elevated transaminases (n = 1), neutropenia (n = 2), anemia (n = 1), lymphopenia (n = 1), and hypokalemia (n = 1). Osteosclerosis contributed to fractures in one patient after 18 courses. Responses in evaluable patients included 1 partial response, 9 stable disease (median 4.5 courses, range 3-18), and 10 progressions. Zoledronic acid pharmacokinetics were similar to adults. Markers of osteoclast activity and serum IL-6 levels decreased with therapy. CONCLUSIONS: Zoledronic acid with metronomic cyclophosphamide is well tolerated with clinical and biologic responses in recurrent/refractory neuroblastoma. The recommended dose of zoledronic acid is 4 mg/m(2) every 28 days.

Differential computed tomographic attenuation of metabolically active and inactive adipose tissues: preliminary findings.

This study investigates differences in computed tomography Hounsfield units between metabolically active (brown fat) and inactive adipose tissues (white fat) due to variations in their densities. Positron emission and computed tomographic data from 101 pediatric and adolescent patients were analyzed. Regions of metabolically active and inactive adipose tissues were identified, and standard uptake values and Hounsfield units were measured. Hounsfield units of active brown fat were more positive (P < 0.001) than inactive fat (-62.4 ± 5.3 vs -86.7 ± 7.0) and the difference was observed in both males and females.

Functional brown adipose tissue is related to muscle volume in children and adolescents.

OBJECTIVE: We examined whether the depiction of brown adipose tissue (BAT) with positron emission tomography/computed tomography (PET/CT) in pediatric patients is associated with anthropometric measures. STUDY DESIGN: We determined measures of body mass, adiposity, and musculature in 71 children and adolescents who underwent PET/CT examinations and compared patients with and without BAT. We used regression analyses to assess the relation between BAT and anthropometric measures. RESULTS: A total of 30 patients (42%) had BAT depicted on PET/CT, 10 of 26 girls (38%) and 20 of 45 boys (44%). Compared with patients without functional BAT, patients with BAT had significantly greater neck musculature (1880 ± 908 cm(3) versus 1299 ± 806 cm(3); P = .028 for boys and 1295 ± 586 cm(3) versus 854 ± 392 cm(3); P = .030 for girls) and gluteus musculature (1359 ± 373 cm(3) versus 1061 ± 500 cm(3); P = .032 for boys and 1138 ± 425 cm(3) versus 827 ± 297 cm(3); P = .038 for girls), but no differences in age, body mass index, or measures of subcutaneous fat. With logistic regression analyses, neck and pelvic musculature predicted the presence of BAT independently of age, sex, body size, and season of scan (P = .018 and .009, respectively). CONCLUSION: Pediatric patients with visualized BAT on PET/CT examinations had significantly greater muscle volume than patients with no visualized BAT.

Fatal infantile lactic acidosis and a novel homozygous mutation in the SUCLG1 gene: a mitochondrial DNA depletion disorder.

Mitochondrial DNA (mtDNA) depletion syndromes are autosomal recessive conditions in which the mtDNA copy number is greatly decreased in affected tissues. The encephalomyopathic group of these syndromes comprise mutations in SUCLA2 and SUCLG1 subunits [1]. In this report, we describe a patient with fatal infantile lactic acidosis associated with mutations in the SUCLG1 gene and mtDNA depletion. Histological and enzymatic abnormalities in skeletal muscle support the diagnosis of this recently described mitochondrial disorder. This case is unique in that prenatal imaging suggested the diagnosis and that the confirmatory molecular diagnosis was established at 2 weeks of age. We describe prenatal MRI and neonatal laboratory disturbances that can point the clinician toward consideration of this diagnosis when treating infantile lactic acidosis.

Contralateral hemimicrencephaly in neonatal hemimegalencephaly.

Identification of abnormalities in the contralateral hemisphere in patients with hemimegalencephaly is critical in their management. In this report, we present a 5-day-old neonate with hemimegalencephaly who demonstrated an enlarged ipsilateral cerebral hemisphere and diffuse volume loss in the contralateral hemisphere on conventional MR imaging sequences. The ipsilateral frontal white matter demonstrated relatively increased NAA, fractional anistropy, and cerebral blood volume values compared to published normative data. In addition, the white matter of the contralateral hemisphere demonstrated elevated lactate and increased mean diffusivity compared to published normative data, supporting the abnormal conventional MR findings. Advanced MR neuroimaging techniques may help further confirm and characterize abnormalities in the smaller contralateral hemisphere in neonatal hemimegalencephaly.