Kunitz-type protease inhibitor TFPI2 remodels stemness and immunosuppressive tumor microenvironment in glioblastoma.

Glioblastoma (GBM) tumors consist of multiple cell populations, including self-renewing glioblastoma stem cells (GSCs) and immunosuppressive microglia. Here we identified Kunitz-type protease inhibitor TFPI2 as a critical factor connecting these cell populations and their associated GBM hallmarks of stemness and immunosuppression. TFPI2 promotes GSC self-renewal and tumor growth via activation of the c-Jun N-terminal kinase-signal transducer and activator of transcription (STAT)3 pathway. Secreted TFPI2 interacts with its functional receptor CD51 on microglia to trigger the infiltration and immunosuppressive polarization of microglia through activation of STAT6 signaling. Inhibition of the TFPI2-CD51-STAT6 signaling axis activates T cells and synergizes with anti-PD1 therapy in GBM mouse models. In human GBM, TFPI2 correlates positively with stemness, microglia abundance, immunosuppression and poor prognosis. Our study identifies a function for TFPI2 and supports therapeutic targeting of TFPI2 as an effective strategy for GBM.

PRMT6 methylation of RCC1 regulates mitosis, tumorigenicity, and radiation response of glioblastoma stem cells.

Aberrant cell proliferation is a hallmark of cancer, including glioblastoma (GBM). Here we report that protein arginine methyltransferase (PRMT) 6 activity is required for the proliferation, stem-like properties, and tumorigenicity of glioblastoma stem cells (GSCs), a subpopulation in GBM critical for malignancy. We identified a casein kinase 2 (CK2)-PRMT6-regulator of chromatin condensation 1 (RCC1) signaling axis whose activity is an important contributor to the stem-like properties and tumor biology of GSCs. CK2 phosphorylates and stabilizes PRMT6 through deubiquitylation, which promotes PRMT6 methylation of RCC1, which in turn is required for RCC1 association with chromatin and activation of RAN. Disruption of this pathway results in defects in mitosis. EPZ020411, a specific small-molecule inhibitor for PRMT6, suppresses RCC1 arginine methylation and improves the cytotoxic activity of radiotherapy against GSC brain tumor xenografts. This study identifies a CK2α-PRMT6-RCC1 signaling axis that can be therapeutically targeted in the treatment of GBM.

Context-Dependent Glioblastoma-Macrophage/Microglia Symbiosis and Associated Mechanisms.

Glioblastoma (GBM) is a lethal form of primary brain tumor in human adults. The impact of tumor-intrinsic alterations is not exclusively confined to cancer cells but can also be extended to the tumor microenvironment (TME). Glioblastoma-associated macrophages/microglia (GAMs) are a prominent type of immune cells that account for up to 50% of total cells in GBM. Emerging evidence suggests that context-dependent GBM-GAM symbiotic interactions are pivotal for tumor growth and progression. Here, we discuss how specific genetic alterations in GBM cells affect GAM biology and, reciprocally, how GAMs support GBM progression. We hypothesize that understanding context-dependent GBM-GAM symbiosis may reveal the molecular basis of GBM tumorigenesis and lead to novel candidate treatment approaches aiming to improve GBM patient outcomes.

Percutaneous cecostomy: 25-year two institution experience.

BACKGROUND: Reports of technical success, adverse events, and long-term outcome of percutaneous cecostomy in children are limited. OBJECTIVE: To characterize technical success, 30-day severe adverse events, and long-term outcome of percutaneous cecostomy at two centers. MATERIALS AND METHODS: A retrospective review of hospital course and long-term follow-up (through May 2022) of percutaneous cecostomy tubes placed May 1997 to August 2011 at two children's hospitals was used. Outcomes assessed included technical success (defined as successful tube placement into the colon allowing antegrade colonic enemas), length of stay, 30-day severe adverse events, surgery consults, surgical repair, VP shunt infection, ongoing flushes, tube removal, duration between maintenance tube exchanges, and deaths. RESULTS: A total of 215 procedures were performed in 208 patients (90 institution A, 125 institution B). Tubes were placed for neurogenic bowel (72.1%, n = 155) and functional constipation (27.9%, n = 60). Technical success was 98.1% (211/215) and did not differ between centers (p = 0.74). Surgical repair was required for bowel leakage in 5.1% (11/215) and VP shunt infection was managed in 2.1% (2/95). Compared to functional constipation, patients with neurogenic bowel had higher % tube remaining (65.3% [96/147] versus 25.9% [15/58], p < 0.001) and higher ongoing flushes at follow-up (42.2% [62/147] versus 12.1% [7/58], p < 0.001). Tube removal for dissatisfaction occurred in 15.6% [32/205] and did not differ between groups (p = 0.98). Eight deaths due to co-morbidity occurred after a median of 7.4 years (IQR 9.3) of tube access. CONCLUSION: Percutaneous cecostomy is technically successful in the vast majority of patients and provided durable access in most. Bowel leakage and VP shunt infection are uncommon, severe adverse events.

Establishing a pediatric interventional radiology inpatient consult service.

OBJECTIVE: To delineate pediatric interventional radiology (IR) inpatient consult growth and resulting collections after implementation of a pediatric IR consult service. METHODS: An inpatient IR consult process was created at a single academic children's hospital in October 2019. IR consult note templates were created in Epic (Epic Systems Corporation, Verona, Wisconsin) and utilized by 4 IR physicians. Automatic charge generation was linked to differing levels of evaluation and management (E&M) service relating to current procedural terminology (CPT) inpatient consult codes 99251-99255. The children's hospital informatics division identified IR consult notes entered from the implementation of the consult service: October 2019 to January 2022. The university radiology department billing office provided IR service E&M charge, payment, and relative value units (RVU) information during this study period. A chart review was performed to determine the IR procedure conversion rate. Mann-Whitney and a two-sample t-test statistical analyses compared use of the 25-modifier, monthly consult growth and monthly payment growth. P-value < 0.05 was considered statistically significant.  RESULTS: Within this 27-month period, a total of 2153 inpatient IR consults were performed during 1757 Epic hospital encounters; monthly consult peak was reached 5 months into the study period. Consult level breakdown by CPT codes: 99251-8.7%, 99252-81.7%, and 99253-8.8%. 69.7% of IR consults had consult-specific billing with payments in 96.4% resulting in $143,976 new revenue. From 2020 to 2021, IR consult volume trended upward by 13.4% (P =0.069), and consult-specific payments increased by 84.1% (P<0.001). IR consult procedure conversion rate was 96.5%. CONCLUSION: An inpatient pediatric IR consult service was quickly established and maintained by four physicians over a 27-month study period. Annual IR consult volume trended upward and consult-specific payments increased, resulting in previously uncaptured IR service revenue.

Fully automated leg tracking of Drosophila neurodegeneration models reveals distinct conserved movement signatures.

Some neurodegenerative diseases, like Parkinsons Disease (PD) and Spinocerebellar ataxia 3 (SCA3), are associated with distinct, altered gait and tremor movements that are reflective of the underlying disease etiology. Drosophila melanogaster models of neurodegeneration have illuminated our understanding of the molecular mechanisms of disease. However, it is unknown whether specific gait and tremor dysfunctions also occur in fly disease mutants. To answer this question, we developed a machine-learning image-analysis program, Feature Learning-based LImb segmentation and Tracking (FLLIT), that automatically tracks leg claw positions of freely moving flies recorded on high-speed video, producing a series of gait measurements. Notably, unlike other machine-learning methods, FLLIT generates its own training sets and does not require user-annotated images for learning. Using FLLIT, we carried out high-throughput and high-resolution analysis of gait and tremor features in Drosophila neurodegeneration mutants for the first time. We found that fly models of PD and SCA3 exhibited markedly different walking gait and tremor signatures, which recapitulated characteristics of the respective human diseases. Selective expression of mutant SCA3 in dopaminergic neurons led to a gait signature that more closely resembled those of PD flies. This suggests that the behavioral phenotype depends on the neurons affected rather than the specific nature of the mutation. Different mutations produced tremors in distinct leg pairs, indicating that different motor circuits were affected. Using this approach, fly models can be used to dissect the neurogenetic mechanisms that underlie movement disorders.

Efficacy of standardizing fibrinolytic therapy for parapneumonic effusion.

BACKGROUND: While chest tube placement with pleural fibrinolytic medication is the established treatment of pediatric empyema, treatment failure is reported in up to 20% of these children. OBJECTIVE: Standardizing fibrinolytic administration among interventional radiology (IR) physicians to improve patient outcomes in pediatric parapneumonic effusion. MATERIALS AND METHODS: We introduced a hospital-wide clinical pathway for parapneumonic effusion (1-2 mg tissue plasminogen activator [tPA] twice daily based on pleural US grade); we then collected prospective data for IR treatment May 2017 through February 2020. These data included demographics, co-morbidities, pediatric intensive care unit (PICU) admission, pleural US grade, culture results, daily tPA dose average, twice-daily dose days, skipped dose days, pleural therapy days, need for chest CT/a second IR procedure/surgical drainage, and length of stay. We compared the prospective data to historical controls with IR treatment from January 2013 to April 2017. RESULTS: Sixty-three children and young adults were treated after clinical pathway implementation. IR referrals increased (P = 0.02) and included higher co-morbidities (P = 0.005) and more PICU patients (P = 0.05). Mean doses per day increased from 1.5 to 1.9 (P < 0.001), twice-daily dose days increased from 38% to 79% (P < 0.001) and median pleural therapy days decreased from 3.5 days to 2.5 days (P = 0.001). No IR patients needed surgical intervention. No statistical differences were observed for gender/age/weight, US grade, need for a second IR procedure or length of stay. US grade correlated with greater positive cultures, need for chest CT/second IR procedure, and pleural therapy days. CONCLUSION: Interventional radiology physician standardization improved on a clinical pathway for fibrinolysis of parapneumonic effusion. Despite higher patient complexity, pleural therapy duration decreased. There were no chest tube failures needing surgical drainage.

Radiation therapy and molecular-targeted agents in preclinical testing for immunotherapy, brain tumors, and sarcomas: Opportunities and challenges.

Despite radiation therapy (RT) being an integral part of the treatment of most pediatric cancers and the recent discovery of novel molecular-targeted agents (MTAs) in this era of precision medicine with the potential to improve the therapeutic ratio of modern chemoradiotherapy regimens, there are only a few preclinical trials being conducted to discover novel radiosensitizers and radioprotectors. This has resulted in a paucity of translational clinical trials combining RT and novel MTAs. This report describes the opportunities and challenges of investigating RT together with MTAs in preclinical testing for immunotherapy, brain tumors, and sarcomas in pediatric oncology. We discuss the need for improving the collaboration between radiation oncologists, biologists, and physicists to improve the reliability, reproducibility, and translational potential of RT-based preclinical research. Current translational clinical trials using RT and MTAs for immunotherapy, brain tumors, and sarcomas are described. The technologic advances in experimental RT, availability of novel experimental tumor models, advances in immunology and tumor biology, and the discovery of novel MTAs together hold considerable promise for good quality preclinical and clinical multimodality research to improve the current rates of survival and toxicity in children afflicted with cancer.

The Masquelet Technique: Can Disposable Polypropylene Syringes be an Alternative to Standard PMMA Spacers? A Rat Bone Defect Model.

BACKGROUND: Usually, the two-stage Masquelet induced-membrane technique for extremity reconstruction begins with a polymethylmethacrylate (PMMA) cement spacer-driven membrane, followed by an autologous cancellous bone graft implanted into the membrane cavity to promote healing of large bone defects. In exceptional cases, spacers made of polypropylene disposable syringes were successfully used instead of the usual PMMA spacers because of a PMMA cement shortage caused by a lack of resources. However, this approach lacks clinical evidence and requires experimental validation before being recommended as an alternative to the conventional technique. QUESTIONS/PURPOSES: To (1) develop and (2) validate a critical-sized femoral defect model in rats for two stages of the Masquelet technique and to (3) compare the biological and bone healing properties of polypropylene-induced membranes and PMMA-induced membranes in this model. METHODS: Fifty male Sprague Dawley rats aged 8 weeks old received a 6-mm femur defect, which was stabilized with an external fixator that was converted into an internal device. In the development phase, the defect was filled with PMMA in 16 rats to determine the most favorable timing for bone grafting. Two rats were excluded since they died of anesthetic complications. The other 14 were successively euthanized after 2 weeks (n = 3), 4 weeks (n = 4), 6 weeks (n = 4), and 8 weeks (n = 3) for induced membrane analyses. In the validation phase, 12 rats underwent both stages of the procedure using a PMMA spacer and were randomly assigned to two groups, whether the induced membrane was preserved or removed before grafting. To address our final objective, we implanted either polypropylene or PMMA spacers into the defect (Masquelet technique Stage 1; n = 11 rats per group) for the period established by the development phase. In each group, 6 of 11 rats were euthanized to compare the biological properties of polypropylene-induced membranes and PMMA-induced membranes using histological qualitative analysis, semiquantitative assessment of the bone morphogenic protein-2 content by immunostaining, and qualitative assessment of the mesenchymal stromal cell (MSC; CD31-, CD45-, CD90+, and CD73+ phenotypes) content by flow cytometry. Quantitative measurements from serum bone turnover markers were also performed. The five remaining rats of each group were used for Masquelet technique Stage 2, in which rat bone allografts were implanted in the induced membrane cavity after the polypropylene or PMMA spacers were removed. These rats recovered for 10 weeks before being euthanized for microCT quantitative measurements and bone histology qualitative assessment to evaluate and compare the extent of bone regeneration between groups. RESULTS: Induced membrane analyses together with serum bone turnover measurements indicated that a 4-week interval time between stages was the most favorable. Removal of the induced membrane before grafting led to almost constant early implant failures with poor bone formation. Four-week-old rats with polypropylene-triggered induced membranes displayed similar histologic organization as rats with PMMA-driven induced membranes, without any difference in the cell density of the extracellular matrix (4933 ± 916 cells per mm2 for polypropylene versus 4923 ± 1284 cells per mm2 for PMMA; p = 0.98). Induced membrane-derived MSCs were found in both groups with no difference (4 of 5 with polypropylene versus 3 of 3 with PMMA; p > 0.99). Induced membrane bone morphogenic protein-2 immunolabeling and serum bone turnover marker levels were comparable between the polypropylene and PMMA groups. MicroCT analysis found that bone regeneration in the polypropylene group seemed comparable with that in the PMMA group (29 ± 26 mm3 for polypropylene versus 24 ± 18 mm3 for PMMA; p > 0.99). Finally, qualitative histological assessment revealed a satisfactory endochondral ossification maturation in both groups. CONCLUSION: Using a critical-sized femoral defect model in rats, we demonstrated that polypropylene spacers could induce membrane encapsulation with histologic characteristics and bone regenerative capacities that seem like those of PMMA spacers. CLINICAL RELEVANCE: In a same bone site, polymers with close physical properties seem to lead to similar foreign body reactions and induce encapsulating membranes with comparable bone healing properties. Polypropylene spacers made from disposable syringes could be a valuable alternative to PMMA. These results support the possibility of a cementless Masquelet technique in cases of PMMA shortage caused by a lack of resources.

Leveraging Multimedia Patient Engagement to Address Minority Cerebrovascular Health Needs: Prospective Observational Study.

BACKGROUND: Social inequities affecting minority populations after Hurricane Katrina led to an expansion of environmental justice literature. In August 2017, Hurricane Harvey rainfall was estimated as a 3000- to 20,000-year flood event, further affecting minority populations with disproportionate stroke prevalence. The Stomp Out Stroke initiative leveraged multimedia engagement, creating a patient-centered cerebrovascular health intervention. OBJECTIVE: This study aims to address social inequities in cerebrovascular health through the identification of race- or ethnicity-specific health needs and the provision of in-person stroke prevention screening during two community events (May 2018 and May 2019). METHODS: Stomp Out Stroke recruitment took place through internet-based channels (websites and social networking). Exclusively through web registration, Stomp Out Stroke participants (aged >18 years) detailed sociodemographic characteristics, family history of stroke, and stroke survivorship. Participant health interests were compared by race or ethnicity using Kruskal-Wallis or chi-square test at an α=.05. A Bonferroni-corrected P value of .0083 was used for multiple comparisons. RESULTS: Stomp Out Stroke registrants (N=1401) were 70% (973/1390) female (median age 45 years) and largely self-identified as members of minority groups: 32.05% (449/1401) Hispanic, 25.62% (359/1401) African American, 13.63% (191/1401) Asian compared with 23.63% (331/1401) non-Hispanic White. Stroke survivors comprised 11.55% (155/1401) of our population. A total of 124 stroke caregivers participated. Approximately 36.81% (493/1339) of participants had a family history of stroke. African American participants were most likely to have Medicare or Medicaid insurance (84/341, 24.6%), whereas Hispanic participants were most likely to be uninsured (127/435, 29.2%). Hispanic participants were more likely than non-Hispanic White participants to obtain health screenings (282/449, 62.8% vs 175/331, 52.9%; P=.03). Asian (105/191, 54.9%) and African American (201/359, 55.9%) participants were more likely to request stroke education than non-Hispanic White (138/331, 41.6%) or Hispanic participants (193/449, 42.9%). African American participants were more likely to seek overall health education than non-Hispanic White participants (166/359, 46.2% vs 108/331, 32.6%; P=.002). Non-Hispanic White participants (48/331, 14.5%) were less likely to speak to health care providers than African American (91/359, 25.3%) or Asian participants (54/191, 28.3%). During the 2018 and 2019 events, 2774 health screenings were completed across 12 hours, averaging four health screenings per minute. These included blood pressure (1031/2774, 37.16%), stroke risk assessment (496/2774, 17.88%), bone density (426/2774, 15.35%), carotid ultrasound (380/2774, 13.69%), BMI (182/2774, 6.56%), serum lipids (157/2774, 5.65%), and hemoglobin A1c (102/2774, 3.67%). Twenty multimedia placements using the Stomp Out Stroke webpage, social media, #stompoutstroke, television, iQ radio, and web-based news reached approximately 849,731 people in the Houston area. CONCLUSIONS: Using a combination of internet-based recruitment, registration, and in-person assessments, Stomp Out Stroke identified race- or ethnicity-specific health care needs and provided appropriate screenings to minority populations at increased risk of urban flooding and stroke. This protocol can be replicated in Southern US Stroke Belt cities with similar flood risks.

Dual bioluminescence and near-infrared fluorescence monitoring to evaluate spherical nucleic acid nanoconjugate activity in vivo.

RNA interference (RNAi)-based gene regulation platforms have shown promise as a novel class of therapeutics for the precision treatment of cancer. Techniques in preclinical evaluation of RNAi-based nanoconjugates have yet to allow for optimization of their gene regulatory activity. We have developed spherical nucleic acids (SNAs) as a blood-brain barrier-/blood-tumor barrier-penetrating nanoconjugate to deliver small interfering (si) and micro (mi)RNAs to intracranial glioblastoma (GBM) tumor sites. To identify high-activity SNA conjugates and to determine optimal SNA treatment regimens, we developed a reporter xenograft model to evaluate SNA efficacy in vivo. Engrafted tumors stably coexpress optical reporters for luciferase and a near-infrared (NIR) fluorescent protein (iRFP670), with the latter fused to the DNA repair protein O6-methylguanine-DNA-methyltransferase (MGMT). Using noninvasive imaging of animal subjects bearing reporter-modified intracranial xenografts, we quantitatively assessed MGMT knockdown by SNAs composed of MGMT-targeting siRNA duplexes (siMGMT-SNAs). We show that systemic administration of siMGMT-SNAs via single tail vein injection is capable of robust intratumoral MGMT protein knockdown in vivo, with persistent and SNA dose-dependent MGMT silencing confirmed by Western blotting of tumor tissue ex vivo. Analyses of SNA biodistribution and pharmacokinetics revealed rapid intratumoral uptake and significant intratumoral retention that increased the antitumor activity of coadministered temozolomide (TMZ). Our study demonstrates that dual noninvasive bioluminescence and NIR fluorescence imaging of cancer xenograft models represents a powerful in vivo strategy to identify RNAi-based nanotherapeutics with potent gene silencing activity and will inform additional preclinical and clinical investigations of these constructs.

Imaging tryptophan uptake with positron emission tomography in glioblastoma patients treated with indoximod.

INTRODUCTION: Glioblastoma (GBM) is the most frequent and aggressive primary tumor of the central nervous system, accounting for over 50% of all primary malignant gliomas arising in the adult brain. Even after surgical resection, adjuvant radiotherapy (RT) and temozolomide (TMZ) chemotherapy, as well as tumor-treating fields, the median survival is only 15-20 months. We have identified a pathogenic mechanism that contributes to the tumor-induced immunosuppression in the form of increased indoleamine 2,3 dioxygenase 1 (IDO1) expression; an enzyme that metabolizes the essential amino acid, tryptophan (Trp), into kynurenine (Kyn). However, real-time measurements of IDO1 activity has yet to become mainstream in clinical protocols for assessing IDO1 activity in GBM patients. METHODS: Pre-treatment and on-treatment α-[11C]-methyl-L-Trp (AMT) positron emission tomography (PET) with co-registered MRI was performed on patients with recurrent GBM treated with the IDO1 pathway inhibitor indoximod (D1-MT) and TMZ. RESULTS: Regional intratumoral variability of AMT within enhancing and non-enhancing tumor was noted at baseline. On treatment imaging revealed decreased regional uptake suggesting IDO1 pathway modulation with treatment. CONCLUSIONS: Here, we have validated the ability to use PET of the Trp probe, AMT, for use in visualizing and quantifying intratumoral Trp uptake in GBM patients treated with an IDO1 pathway inhibitor. These data serve as rationale to utilize AMT-PET imaging in the future evaluation of GBM patients treated with IDO1 enzyme inhibitors.

Risk factors and failures in the management of limb injuries in combat casualties.

INTRODUCTION: Treatment of war wounds is based on a sequential surgical strategy, which frequently faces therapeutic failures, which then burden the final functional result. The aim of this study was to identify risk factors of failure of the different treatments to prevent the therapeutic failure. METHODS: A monocentric case-control study was done on French war-wounded soldiers treated for an open fracture caused by an invasive war weapon. The primary end point was the treatment failure three months after the injury. The risk factors of failure studied were the traumatic mechanism, the general and local lesional assessment, and the surgery performed. RESULTS: Between January 1, 2004 and December 31, 2016, 57 soldiers were included, with an average follow-up of 3.42 years. On 81 limb segments studied, the most injured segment was the leg (37.0%). A vital or urgent surgery requirement (OR = 1.56; p = 0.02) and bone loss substance (OR = 5.45; CI95% = 1.54-20.09) were risk factors of failure for limb salvage treatment. Improvised explosive device traumatic mechanism (OR = 1.56; p = 0.02) and the persistence of surgical site contamination after two debridement procedures (OR = 1.20; p = 0.04) were risk factors of failure for amputation procedures. CONCLUSIONS: Two main risk factors of treatment failure are highlighted: those in relation to traumatic mechanisms and general lesional assessment and those in relation to surgical site conditions. There is no over risk of failure in relation to surgical procedure and treatment.

An overview of meningiomas.

Meningiomas are the most common primary intracranial tumor. Important advances are occurring in meningioma research. These are expected to accelerate, potentially leading to impactful changes on the management of meningiomas in the near and medium term. This review will cover the histo- and molecular pathology of meningiomas, including recent 2016 updates to the WHO classification of CNS tumors. We will discuss clinical and radiographic presentation and therapeutic management. Surgery and radiotherapy, the two longstanding primary therapeutic modalities, will be discussed at length. In addition, data from prior and ongoing investigations of other treatment modalities, including systemic and targeted therapies, will be covered. This review will quickly update the reader on the contemporary management and future directions in meningiomas. [Formula: see text].

Diffuse vasospasm after transcortical temporal lobectomy for intractable epilepsy.

Cerebral delayed ischemia due to arterial vasospasm is a rare complication following epilepsy surgery. Here we report the third known case and first of diffuse vasospasm. A 48-year-old woman underwent a transcortical anterior left temporal lobectomy. Eleven days later, she had new-onset expressive aphasia with narrowing of the anterior, middle, and posterior cerebral arteries, and increased velocities via transcranial Doppler. She was treated with fluids, nimodipine, and permissive hypertension. At 6 months, her speech was near baseline. Cerebral vasospasm may represent a rare cause of morbidity after anterior temporal lobectomy; a literature review on the subject is presented.

Targeting CD133 improves chemotherapeutic efficacy of recurrent pediatric pilocytic astrocytoma following prolonged chemotherapy.

BACKGROUND: Pilocytic astrocytomas (PAs) are the most common pediatric central nervous system neoplasms. In the majority of cases these tumors are benign and receive favorable prognosis following gross total surgical resection. In patients with progressive or symptomatic tumors, aggressive surgical resection is generally not feasible, thus radiation or chemotherapy are accepted initial or adjuvant interventions. Due to serious long-lasting side-effects, radiation is limited in young children; therefore, chemotherapy is widely practiced as an adjuvant treatment for these patients. However, chemotherapy can promote the emergence of multidrug resistant tumor cells that are more malignant than those of the original tumor. CD133, a putative stem cell marker in normal tissue and malignant brain tumors, enhances multidrug resistant gene 1 (MDR1) expression following chemotherapy in adult malignant glioblastomas. This study examines the relationship between CD133 and MDR1 in pediatric PAs exposed to chemotherapy, with the goal of identifying therapeutic targets that manifest as a result of chemotherapy. METHODS: Slides were obtained for 15 recurrent PAs, seven of which had received chemotherapy prior to surgical treatment for the recurrent tumor. These samples, as well as primary tumor tissue slides from the same patients were used to investigate CD133 and MDR1 expression via immunofluorescence. Archived frozen tissue samples from the same patients were used to examine CD133, MDR1 and PI3K-Akt-NF-κB signaling mediators, via western blot. Two drug resistant pediatric PA cell lines Res186 and Res199 were also used to evaluate the role of CD133 on cell response to cytotoxic therapy. RESULTS: CD133 and MDR1 were co-expressed and their expression was elevated in recurrent PAs from patients that had received chemotherapy, compared to patients that had not received chemotherapy. PI3K-Akt-NF-κB signaling mediator expression was also elevated in recurrent, chemotherapy-treated PA. Suppressing CD133 expression with siCD133 decreased levels of PI3K-Akt-NF-κB signaling mediators and MDR1, while increasing cell chemosensitivity, as indicated by quantification of apoptotic cells following chemotherapy. CONCLUSIONS: CD133 contributes to multidrug resistance by regulating MDR1 levels via the PI3K-Akt-NF-κB signal pathway not only in adult glioblastomas, but also in pediatric PAs. Targeting CD133, adjuvant to conventional chemotherapy may improve outcomes for children with recurrent PA.

Middle cerebral artery aneurysm rupture in a neonate with interrupted aortic arch: case report.

INTRODUCTION: Arterial cerebral aneurysms in the neonatal population are rare, and while the association of interrupted aortic arch and intracranial aneurysm has been reported in the adult and pediatric population (three cases each), to date, it has not been reported in the neonate. CASE REPORT: We report the case of a 26-day-old girl who presented with a generalized seizure 2 weeks after undergoing congenital heart surgery. Head CT revealed diffuse SAH with a 1.7 × 2.9-cm frontal intra-parenchymal hematoma with subdural extension producing 3 mm of midline shift. CTA evidenced a 2-mm left MCA bifurcation aneurysm, and the patient was taken to the operating room for clipping. Twenty-four-hour post-operative head CT showed ventriculomegaly and an EVD was placed. It was removed 4 days later without the need for permanent CSF diversion, and after this, her hospital stay was uneventful and she was discharged home. At 25 months of age, she was meeting developmental milestones. At this time, she underwent further heart surgery and expired shortly thereafter due to cardiomyopathy. CONCLUSION: Here, we report the successful treatment of a ruptured neonatal aneurysm, and the first known case associated with interrupted aortic arch. Given the time and presentation, this patient likely illustrates the role of hemodynamic factors in the rupture of neonatal aneurysms. In reviewing all of the reported cases of neonatal aneurysms, promptly securing the aneurysm by either open clipping, parent vessel occlusion, or endovascular coiling is strongly preferable to no surgical intervention.

Stratifying fibrinolytic dosing in pediatric parapneumonic effusion based on ultrasound grade correlation.

BACKGROUND: Complicated pleural effusion prolongs the hospital course of pneumonia. Chest tube placement with instillation of fibrinolytic medication allows efficient drain output and decreases hospital stay. OBJECTIVE: To evaluate experience with lower fibrinolytic dose for parapneumonic effusions and to assess potential dose stratification based on a simple ultrasound grading system. MATERIALS AND METHODS: We retrospectively reviewed the medical record to identify children and young adults who received fibrinolytic therapy for parapneumonic effusion and had chest tube placement by an interventional radiology service at a single children's hospital. We assessed tissue plasminogen activator (tPA) dosing and treatment duration, as well as the need for a second pleural procedure or surgical drainage. Diagnostic US images were classified as showing less than 50% pleural echogenicity (grade 1) or greater than 50% pleural echogenicity (grade 2) and were correlated with clinical parameters. RESULTS: Of 32 patients with parapneumonic effusion, all except one received at least some 1-mg tPA doses. Dosing was solely 1-mg tPA in 81% of subjects; 19% of subjects also received 2-mg tPA doses. Mean fibrinolytic duration was 3.1 days for grade 1 effusions compared to 5.4 days for grade 2 effusions. A second pleural procedure was required in 15.6% of children. Pleural drainage with fibrinolytic therapy was successful in 97%; only one child required surgical drainage. Grade 2 US differed significantly from grade 1 US, with grade 2 occurring in younger patients (P < 0.0001), smaller patients (P < 0.0001), those needing a second procedure (P = 0.001), those with positive pleural culture or polymerase chain reaction test (P = 0.006), and those with longer treatment duration (P = 0.03). CONCLUSION: A lower 1-mg dosing regimen of tissue plasminogen activator was effective in all children with less complex (grade 1 US imaging) parapneumonic effusions. Grade 2 US images correlated with younger and smaller children, presence of a pleural organism, and longer or more complicated chest tube duration.

Pediatric interventional radiology workforce survey: 10-year follow-up.

BACKGROUND: Pediatric interventional radiology is a distinct subspecialty differing from both pediatric diagnostic radiology and adult interventional radiology. We conducted a workforce survey in 2005 to evaluate the state of pediatric interventional radiology at that time. Since then there have been many advancements to the subspecialty, including the founding of the Society for Pediatric Interventional Radiology (SPIR). OBJECTIVE: To evaluate the current state of the pediatric interventional radiology workforce and compare findings with those of the initial 2005 workforce survey. MATERIALS AND METHODS: We sent a two-part survey electronically to members of SPIR, the Society for Pediatric Radiology (SPR), the Society of Chairmen of Radiology in Children's Hospitals (SCORCH) and the Society of Interventional Radiology (SIR). Part 1 focused on individual practitioners (n=177), while part 2 focused on group practices and was answered by a leader from each group (n=88). We examined descriptive statistics and, when possible, compared the results to the study from 2005. RESULTS: A total of 177 individuals replied (a 331% increase over the first study) and 88 pediatric interventional radiology (IR) service sites responded (a 131.6% increase). Pediatric IR has become a more clinically oriented specialty, with a statistically significant increase in services with admitting privileges, clinics and performance of daily rounds. Pediatric IR remains diverse in training and practice. Many challenges still exist, including anesthesia/hospital support, and the unknown impact of the new IR residency on pediatric IR training, although the workforce shortage has been somewhat alleviated, as demonstrated by the decreased mean call from 165 days/year to 67.2 days/year. CONCLUSION: Pediatric interventional radiology practitioners and services have grown significantly since 2005, although the profile of this small subspecialty has changed and some challenges remain.