ACR Appropriateness Criteria® Urinary Tract Infection-Child: 2023 Update.

Urinary tract infection (UTI) is a frequent infection in childhood. The diagnosis is usually made by history and physical examination and confirmed by urine analysis. Cystitis is infection or inflammation confined to the bladder, whereas pyelonephritis is infection or inflammation of kidneys. Pyelonephritis can cause renal scarring, which is the most severe long-term sequela of UTI and can lead to accelerated nephrosclerosis, leading to hypertension and chronic renal failure. The role of imaging is to guide treatment by identifying patients who are at high risk to develop recurrent UTIs or renal scarring. This document provides initial imaging guidelines for children presenting with first febrile UTI with appropriate response to medical management, atypical or recurrent febrile UTI, and follow-up imaging for children with established vesicoureteral reflux. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Indoximod-based chemo-immunotherapy for pediatric brain tumors: A first-in-children phase I trial.

BACKGROUND: Recurrent brain tumors are the leading cause of cancer death in children. Indoleamine 2,3-dioxygenase (IDO) is a targetable metabolic checkpoint that, in preclinical models, inhibits anti-tumor immunity following chemotherapy. METHODS: We conducted a phase I trial (NCT02502708) of the oral IDO-pathway inhibitor indoximod in children with recurrent brain tumors or newly diagnosed diffuse intrinsic pontine glioma (DIPG). Separate dose-finding arms were performed for indoximod in combination with oral temozolomide (200 mg/m2/day x 5 days in 28-day cycles), or with palliative conformal radiation. Blood samples were collected at baseline and monthly for single-cell RNA-sequencing with paired single-cell T cell receptor sequencing. RESULTS: Eighty-one patients were treated with indoximod-based combination therapy. Median follow-up was 52 months (range 39-77 months). Maximum tolerated dose was not reached, and the pediatric dose of indoximod was determined as 19.2 mg/kg/dose, twice daily. Median overall survival was 13.3 months (n = 68, range 0.2-62.7) for all patients with recurrent disease and 14.4 months (n = 13, range 4.7-29.7) for DIPG. The subset of n = 26 patients who showed evidence of objective response (even a partial or mixed response) had over 3-fold longer median OS (25.2 months, range 5.4-61.9, p = 0.006) compared to n = 37 nonresponders (7.3 months, range 0.2-62.7). Four patients remain free of active disease longer than 36 months. Single-cell sequencing confirmed emergence of new circulating CD8 T cell clonotypes with late effector phenotype. CONCLUSIONS: Indoximod was well tolerated and could be safely combined with chemotherapy and radiation. Encouraging preliminary evidence of efficacy supports advancing to Phase II/III trials for pediatric brain tumors.

Imaging of Vertebral Artery Dissection in Children: An Underrecognized Condition with High Risk of Recurrent Stroke.

Vertebral artery dissection (VAD) is a common cause of a rare condition, pediatric posterior circulation arterial ischemic stroke (PCAIS). VAD is clinically important due to the risk of multifocal and continuing infarcts from artery-to-artery thromboembolism, with the potential for occlusion of arteries that perfuse the brainstem. Early diagnosis is important, as recurrent stroke is a common effect of VAD in children. Although the relative efficacies of different treatment regimens for VAD in children remain unsettled, early initiation of treatment can mitigate the risk of delayed stroke. Clinical diagnosis of PCAIS may be delayed due to multiple factors, including nonspecific symptoms and the inability of younger patients to express symptoms. In fact, subacute or chronic infarcts are often present at initial imaging. Although the most common cause of isolated PCAIS is VAD, imaging of the cervical arteries has been historically underused in this setting. Cervical vascular imaging (MR angiography, CT angiography, and digital subtraction angiography) for VAD must be optimized to detect the sometimes subtle findings, which may be identified at initial or follow-up imaging. Osseous variants of the craniocervical junction and upper cervical spine and other extrinsic lesions that may directly injure the vertebral arteries or lead to altered biomechanics have been implicated in some cases. The authors review characteristic imaging features and optimized imaging of VAD and associated PCAIS and related clinical considerations. Identification of VAD has important implications for evaluation, treatment, and imaging follow-up, as this condition may result in progressive arteriopathy and recurrent stroke. © RSNA, 2023 Supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.

Single-molecule analysis of osmolyte-mediated nanomechanical unfolding behavior of a protein domain.

The small organic molecules, known as osmolytes being ubiquitously present in different cell types, affect protein folding, stability and aggregation. However, it is unknown how the osmolytes affect the nanomechanical unfolding behavior of protein domain. Here, we show the osmolyte-dependent mechanical unfolding properties of protein titin immunoglobulin-27 (I27) domain using an atomic force microscopy (AFM)-based single-molecule force spectroscopy. We found that amines and methylamines improved the mechanical stability of I27 domain, whereas polyols had no effect. Interestingly, glycine betaine (GB) or trimethylamine-N-oxide (TMAO) increased the average unfolding force of the protein domain. The kinetic parameters analyzed at single-molecule level reveal that stabilizing effect of osmolytes is due to a decrease in the unfolding rate constant of I27, which was confirmed by molecular dynamics simulations. Our study reveals different effects that diverse osmolytes have on the mechanical properties of the protein, and suggests the potential use of osmolytes in modulating the mechanical stability of proteins required for various nano-biotechnological applications.

Quantification of adsorbed and dangling citrate ions on gold nanoparticle surface using thermogravimetric analysis.

A novel approach involving thermo-gravimetricanalysis (TGA) for the quantification of citrate ions present on the surface of gold nanoparticles has been reported. TGA study was carried out on AuNPs in response to parameters such as concentration of tri-sodium citrate and pH of gold nanoparticles depicting that the number of citrate ion present on gold nanoparticles is highly pH dependent. In general, the citrate ions were observed to be higher in alkaline conditions contradicting earlier beliefs. These results also underline the significance of TGA as a novel tool for quantification of citrate molecules present on gold nanoparticle surface. Thus, the present approach not only provides with an insight into mechanistic details of gold nanoparticle synthesis but also opens the usage of TGA for understanding the nano range association of molecules.

Head and Neck Sarcomas: A Review of Clinical and Imaging Findings Based on the 2013 World Health Organization Classification.

OBJECTIVE: Head and neck sarcomas are a complex, heterogeneous group of tumors that present a diagnostic challenge to radiologists because they have many overlapping imaging features. The purpose of this article is to review the imaging and clinical features and highlight distinguishing features of head and neck sarcomas. CONCLUSION: An understanding of characteristic imaging and clinical features of head and neck sarcomas is important for the radiologist to narrow the differential diagnosis and help guide management.

Peptide Functionalized Metallic Nanoconstructs: Synthesis, Structural Characterization, and Antimicrobial Evaluation.

Biomolecule based conjugation of metallic nanoparticles has become an important area of research lately especially considering the role of such nanoconjugates in diverse applications. Herein, synthesis of cationic dipeptide conjugated gold/silver nanoparticles through the covalent approach using carbodiimide cross-linker chemistry has been reported. Owing to the exceptional optoelectronic properties of metallic nanoparticles, peptide-gold/silver nanoparticle conjugates were synthesized employing 2-mercaptopropanoic acid as a cross-linker. The conjugates were further compared with their noncovalently synthesized counterparts using ultraviolet-visible spectroscopy. It was generally observed that the conjugates synthesized using the covalent approach were more stable than the conventional noncovalent approach. The synthesized conjugates were further evaluated for their antimicrobial efficacy. The experimental findings demonstrated that peptide capped silver nanoparticles possessed relatively better antimicrobial activity than peptide capped gold nanoparticles, native peptides as well as unconjugated gold/silver nanoparticles which was also evident in time kill assay studies. The morphological effects of active compounds on Escherichia coli and Candida albicans exhibited complete disruption of the cell wall. Thus, this study is an important step toward the opening up of avenues for the applicability of the covalent approach for functionalization of metallic nanoparticles with not only short peptide based systems but also for other biomolecules in areas such as anti-infectives, drug delivery, and bioimaging.

Stabilized cationic dipeptide capped gold/silver nanohybrids: Towards enhanced antibacterial and antifungal efficacy.

The nanoparticles of silver/gold and cationic peptides have been recognized as potent antimicrobials for long, but their combined effect has so far not been explored. The present study reports the green synthesis of short cationic dipeptide stabilized AuNPs/AgNPs based nanohybrid materials. It thoroughly investigates the effect of conjugation of short cationic peptides on the antimicrobial properties of metallic nanoparticles. In the context of the antimicrobial evaluation of synthesized nanoconjugates, it was observed that peptide capped AgNPs exhibited higher antimicrobial activity as compared to peptide capped AuNPs as well as native peptides and unconjugated metallic nanoparticles. Specifically, l-His-l-Arg-OMe capped AgNPs exhibited MIC of 0.50, 0.37 and 0.25µM against E.coli, S. aureus and S. typhimurium respectively and MIC of 0.80 and 10.00µM against C. albicans and C. glabrata respectively. These results indicate that synthetic dipeptides render AgNPs as better antimicrobial agents in comparison to the native AgNPs and positively charged dipeptides. In addition, the time kill profile of cationic peptide (l-His-l-Arg-OMe) capped AgNPs was found to be even better than the known antibiotics. The cytotoxic behavior of all synthesized nanoconjugates of cationic peptides was studied and was found to be within acceptable limits. The present study opens a completely new class of antimicrobials for combating a wide range of bacterial and fungal pathogens. Another interesting and crucial finding was that dipeptide capped AgNPs displayed maximum antimicrobial activity with observed approximate 2-10 fold reduction in nano formulation dosage against tested microbes.

Self-assembly of aromatic α-amino acids into amyloid inspired nano/micro scaled architects.

In the pursuit for design of novel bio inspired materials, aromatic α-amino acids (phenylalanine, tyrosine, tryptophan and histidine) have been investigated for the generation of well-ordered self-assembled architects such as fibrils, rods, ribbons and twisted nanosheets in varying solvent systems. These nano/micro scaled architects were thoroughly characterized using FE-SEM, confocal microscopy, optical microscopy, 1H NMR, FTIR, XRD and TGA. These self-assembled architects were histologically stained with Congo red and thioflavin T dyes for investigation of amyloid morphology which revealed that the deposited state of ordered assemblies exhibit specific characteristic of amyloid deposits. The self-assembly of aromatic amino acids was observed to be driven by non-covalent forces such as π-π stacking, van der Waals and electrostatic interaction.

A simplified algorithm for diagnosis of spinal cord lesions.

Neuroimaging is indispensable for evaluation of Myelopathy not only for localization but also for etiologic determination. MRI is the preferred examination for further characterization of the majority of these conditions. These include traumatic, inflammatory, infections, compressive and neoplastic conditions. This article provides an overview of a variety of pathologies that afflict the spinal cord in an easy to understand format. Their respective imaging manifestations on MRI and differential diagnoses are focused in this review. Early diagnosis and treatment of Myelopathy is critical in preventing or arresting neurological morbidity.

One pot, rapid and efficient synthesis of water dispersible gold nanoparticles using alpha-amino acids.

A detailed study on the synthesis of spherical and monodispersed gold nanoparticles (AuNPs) using all of the 20 naturally occurring α-amino acids has been reported. The synthesized nanoparticles have been further characterized using various techniques such as absorbance spectroscopy, transmission electron microscopy, dynamic light scattering and nuclear magnetic resonance. Size control of the nanoparticles has been achieved by varying the ratio of the gold ion to the amino acid. These monodispersed water soluble AuNPs synthesized using non-toxic, naturally occurring α-amino acids as reducing and capping/stabilizing agents serve as a remarkable example of green chemistry.

Role of plain abdominal radiographs in predicting type of congenital pouch colon.

BACKGROUND: Congenital pouch colon (CPC) is a rare form of high ano-rectal malformation (ARM) in which part of or the entire colon is replaced by a pouch with a fistula to the genito-urinary tract. According to the Saxena-Mathur classification CPC is divided into five types. Although plain abdominal radiographs are taken in infants with suspicion of CPC to detect large dilatation of the pouch, the determination of the type of CPC is made during surgical exploration. Since large variations in the length of normal colon are present in the various types, management strategy options can be determined only at the time of surgery. OBJECTIVE: The aim of this study was to review abdominal radiographs of children with congenital pouch colon (CPC) and evaluate their value in determining the type of CPC prior to surgical exploration to assist pre-operative planning. MATERIALS AND METHODS: Over a 12-year period (1995-2007), CPC was documented in 80 children (52 boys and 28 girls, age range 1 day-9 years, median 2.4 days) and retrospective analysis of plain abdominal radiographs of 77 children at the time of presentation was performed. Radiographic findings were correlated with surgical findings. RESULTS: Of 77 children, 5 were excluded from the study since the pouch colon was perforated. The direction of the pouch apex was correlated with surgical findings to determine the CPC type (P<0.0001, Fisher exact test). Type 1 (17/18) and type 2 CPC (18/18) were characterized by a single large pouch with the apex positioned in the left hypochondrium. In type 3 CPC (2/2) the pouch apex was directed towards the right hypochondrium. In type 4 CPC the apex of the pouch was directed towards the right hypochondrium (28/33); however in 5 children it was towards the left hypochondrium. In type 5 CPC (n=1) the radiograph was inconclusive. CONCLUSION: Plain abdominal radiographs have a predictive value in determining the type of CPC and obviating the need for an invertogram.

Case report: Congenital absence of the dens.

A 36-year-old man presented with headache and right upper and lower limb weakness for 10 days. MRI revealed absence of the odontoid process of the C2 vertebral body, with resultant atlantoaxial dislocation along with myelomalacic changes involving the cervicomedullary junction.

Long-segment intramedullary spinal dermoid.

A 30-year-old man presented with a fairly large intramedullary mass lesion involving virtually the entire spinal cord. It was hyperintense on both T1W and T2W sequences, with signal suppression on fat-saturation images. Subsequent noncontrast CT scan of the spine confirmed the presence of fat and calcification within the lesion, thus leading to the diagnosis of an intramedullary dermoid.

Case report: Epidermoid cyst misdiagnosed as a loculated pericardial effusion.

A 25-year old man presented with a mediastinal lesion which was initially diagnosed as a loculated pericardial collection on echocardiography. Subsequent imaging showed it to be a cystic mediastinal mass, and following surgery and histopathology, it turned out to be an epidermoid cyst.