Second-look surgery in postoperative pediatric low-grade glioma.

OBJECTIVE: To review the literature on second-look surgery in pediatric low-grade gliomas (LGG) with a view to presenting both sides of the picture of re-exploration. METHODS: Collection of material from recent literature on pediatric LGG. This was a retrospective review of these publications. RESULTS: There are a number of publications recommending second-look surgery in selected cases, provided morbidity of the second surgery is minimum, and indeed some in which there is improvement in the neurodeficit after the second resection. CONCLUSION: There seems a fair balance of articles recommending and dissuading the practice of second-look surgery, but in our limited experience we have found it useful in selected patients.

Pediatric spinal instrumentation.

This article reviews the evolution of spinal instrumentation in the pediatric age group, starting with the cervical spine and atlantoaxial area and ending with the lower spine. The congenital and the acquired conditions which require instrumentation are described. The technical details regarding pediatric instrumentation are alluded to, and finally an attempt is made to predict the future of spinal instrumentation in this age group.

B-site order/disorder in A2BB'O6and its correlation with their magnetic property.

The disorder in any system affects their physical behavior. In this scenario, we report the possibility of disorder in A2BB'O6oxides and their effect on different magnetic properties. These systems show anti-site disorder by interchanging B and B' elements from their ordered position and giving rise to an anti-phase boundary. The presence of disorder leads to a reduction in saturationMand magnetic transition temperature. The disorder prevents the system from sharp magnetic transition which originates short-range clustered phase (or Griffiths phase) in the paramagnetic region just above the long-range magnetic transition temperature. Further, we report that the presence of anti-site disorder and anti-phase boundary in A2BB'O6oxides give different interesting magnetic phases like metamagnetic transition, spin-glass, exchange bias, magnetocaloric effect, magnetodielectric, magnetoresistance, spin-phonon coupling, etc.

Hypophysitis - A Review of Fourteen Cases.

Background: Primary hypophysitis is a rare condition, usually diagnosed retrospectively after surgery for a suspected pituitary adenoma. Improved awareness of the condition and better imaging have resulted in more patients being diagnosed without surgery. Objective: A retrospective chart analysis study of hypophysitis from a single secondary endocrine and neurosurgical referral center in eastern India was conducted between 1999 and 2021 to assess the diagnostic and therapeutic challenges posed by these patients. Methods and Material: Fourteen patients presented to the center between 1999 and 2021. All patients had an MRI of the head with contrast and a full clinical workup. Twelve patients had headache, of whom one had progressive visual impairment. One patient had severe weakness, attributed later to hypoadrenalism and one had sixth nerve palsy. Results: Six patients had glucocorticoids as their primary treatment, four refused treatment, and one was on glucocorticoid replacement. One patient had decompressive surgery because of progressive visual loss, and two had surgery because of a presumptive diagnosis of pituitary adenoma. There was no difference between the patients who had glucocorticoids and those who did not. Conclusions: Our data suggest that it is possible to identify most patients with hypophysitis on clinical and radiological grounds. In the largest published series on this subject and in ours, glucocorticoid treatment did not alter the outcome.

An Automated, Home-Cage, Video Monitoring-based Mouse Frailty Index Detects Age-associated Morbidity in C57BL/6 and Diversity Outbred Mice.

Frailty indexes (FIs) provide quantitative measurements of nonspecific health decline and are particularly useful as longitudinal monitors of morbidity in aging studies. For mouse studies, frailty assessments can be taken noninvasively, but they require handling and direct observation that is labor-intensive to the scientist and stress inducing to the animal. Here, we implement, evaluate, and provide a refined digital FI composed entirely of computational analyses of home-cage video and compare it to manually obtained frailty scores in both C57BL/6 and genetically heterogeneous Diversity Outbred mice. We show that the frailty scores assigned by our digital index correlate with both manually obtained frailty scores and chronological age. Thus, we provide an automated tool for frailty assessment that can be collected reproducibly, at scale, without substantial labor cost.

Developing consensus for the management of pediatric cervical spine disorders and stabilization: a modified Delphi study.

OBJECTIVE: Cervical spine disorders in children are relatively uncommon; therefore, paradigms for surgical and nonsurgical clinical management are not well established. The purpose of this study was to bring together an international, multidisciplinary group of pediatric cervical spine experts to build consensus via a modified Delphi approach regarding the clinical management of children with cervical spine disorders and those undergoing cervical spine stabilization surgery. METHODS: A modified Delphi method was used to identify consensus statements for the management of children with cervical spine disorders requiring stabilization. A survey of current practices, supplemented by a literature review, was electronically distributed to 17 neurosurgeons and orthopedic surgeons experienced with the clinical management of pediatric cervical spine disorders. Subsequently, 52 summary statements were formulated and distributed to the group. Statements that reached near consensus or that were of particular interest were then discussed during an in-person meeting to attain further consensus. Consensus was defined as ≥ 80% agreement on a 4-point Likert scale (strongly agree, agree, disagree, strongly disagree). RESULTS: Forty-five consensus-driven statements were identified, with all participants willing to incorporate them into their practice. For children with cervical spine disorders and/or stabilization, consensus statements were divided into the following categories: A) preoperative planning (12 statements); B) radiographic thresholds of instability (4); C) intraoperative/perioperative management (15); D) postoperative care (11); and E) nonoperative management (3). Several important statements reaching consensus included the following recommendations: 1) to obtain pre-positioning baseline signals with intraoperative neuromonitoring; 2) to use rigid instrumentation when technically feasible; 3) to provide postoperative external immobilization for 6-12 weeks with a rigid cervical collar rather than halo vest immobilization; and 4) to continue clinical postoperative follow-up at least until anatomical cervical spine maturity was reached. In addition, preoperative radiographic thresholds for instability that reached consensus included the following: 1) translational motion ≥ 5 mm at C1-2 (excluding patients with Down syndrome) or ≥ 4 mm in the subaxial spine; 2) dynamic angulation in the subaxial spine ≥ 10°; and 3) abnormal motion and T2 signal change on MRI seen at the same level. CONCLUSIONS: In this study, the authors have demonstrated that a multidisciplinary, international group of pediatric cervical spine experts was able to reach consensus on 45 statements regarding the management of pediatric cervical spine disorders and stabilization. Further study is required to determine if implementation of these practices can lead to reduced complications and improved outcomes for children.

Double glassy states and large spontaneous and conventional exchange bias in La1.5Ca0.5CoFeO6ferrimagnetic double perovskite.

The structural and magnetic properties of hole doped double perovskite La1.5Ca0.5CoFeO6have been investigated by measuring x-ray photoemission spectroscopy, neutron powder diffraction and magnetization. A ferrimagnetic transition is observed atTC∼ 167 K. The presence of anti-site disorder (ASD) in La1.5Ca0.5CoFeO6has also been demonstrated. Double re-entrant cluster glass transitions (T1∼ 11 K andTS∼ 35 K) were observed which has been attributed to the ASD effect. The presence of both large spontaneous exchange biasHSEB∼ 2.106 kOe and giant conventional exchange biasHCEB∼ 1.56 T at 5 K has also been observed which can be attributed to the coexistence of long range magnetic ordering and glassy state. The experimental observations were explained with the results obtained by the density functional theory calculation. The presence of double glassy states, large exchange-bias effect and different magnetic phases make this system a potential candidate for spintronic applications.

Anharmonic phonon interactions and the Kondo effect in a FeSe/Sb2Te3/FeSe heterostructure: a proximity effect between ferromagnetic chalcogenide and di-chalcogenide.

In this report, we have introduced magnetic ordering into the nontrivial system of conventional topological insulators (TIs) by creating magnetic interfaces. In this context, antimony di-chalcogenide Sb2Te3 sandwiched between two thin layers of FeSe was prepared using the pulsed laser deposition (PLD) technique. The prepared heterostructure demonstrated good crystallinity along with homogeneous morphology displaying pyramid-shaped characteristic triangular islands. To comprehend the temperature and magnetic field modulated inter-layer properties of the prepared hetero-structure, transport, magneto-transport and magnetic properties were investigated. These properties establish the signature of the Kondo effect below 15 K, which has been attributed to the antiferromagnetic spin alignment in that temperature range. At around 150 K, longitudinal and transverse resistivity shows the metal-semiconductor transition, which was further elucidated through the anharmonic decay model in vibration phonon modes using Raman spectroscopy. Furthermore, a significant local spin evolution was explored at around 475 K by studying the magnetic properties of the system. The temperature dependency of the Raman modes confirmed the spin-phonon coupling initiated by local charge ordering at the proximity of the interface in the prepared hetero-structure.

Ventriculocholecystal Shunt as a Salvage Procedure in Shunt Dependent Hydrocephalic Children with Compromised Peritoneal Cavity.

Multiple shunt revisions are a formidable challenge in neurosurgery, as the surgeon faces progressive difficulties in finding suitable distal sites for implantation. Gallbladder offers an alternative safe implantation site of distal catheter in case of repeated peritoneal failures. We describe two such cases done in our institute in this brief report. One case has long term functioning shunt, whist other had complications. Relevant literature is also briefly reviewed here.

Comparison of Frozen Section and Squash Cytology as Intra-Operative Diagnostic Tool in Pediatric CNS Tumors.

Background: Pediatric central nervous system (CNS) tumors have a different histological spectrum as compared to adults with the infantile group having even more varied and distinct histological profiles. Intra-operative diagnosis is especially important as it guides the neurosurgeon to tailor an approach which is best suited for a particular case. The aim of the study was to evaluate the diagnostic accuracy, sensitivity, specificity, positive predictive value, negative predictive value of frozen section (FS) and squash cytology and to find out the degree of correlation (kappa value) between the two procedures. Materials and Methods: A prospective study was conducted on 55 pediatric patients with clinicoradiologically diagnosed CNS lesions for a period of 2.5 years. Intra-operative squash smears and FS were made and stained with hematoxylin and eosin stain. Diagnosis made subsequently on paraffin embedded sections was taken as the gold standard. Results: Although the specificity (90%) and positive predictive value (96%) were comparable between the two procedures, sensitivity (91.4%) and negative predictive value (75%) of FS was more as compared to squash cytology. Both the diagnostic modalities showed substantial agreement (k = 0.728). Conclusion: Even though the histological spectrum of pediatric CNS tumors is more varied than adults, FS gives a reasonable intra-operative diagnosis and better results when compared to squash alone.

Quantitative Metaproteomics and Activity-based Protein Profiling of Patient Fecal Microbiome Identifies Host and Microbial Serine-type Endopeptidase Activity Associated With Ulcerative Colitis.

The gut microbiota plays an important yet incompletely understood role in the induction and propagation of ulcerative colitis (UC). Organism-level efforts to identify UC-associated microbes have revealed the importance of community structure, but less is known about the molecular effectors of disease. We performed 16S rRNA gene sequencing in parallel with label-free data-dependent LC-MS/MS proteomics to characterize the stool microbiomes of healthy (n = 8) and UC (n = 10) patients. Comparisons of taxonomic composition between techniques revealed major differences in community structure partially attributable to the additional detection of host, fungal, viral, and food peptides by metaproteomics. Differential expression analysis of metaproteomic data identified 176 significantly enriched protein groups between healthy and UC patients. Gene ontology analysis revealed several enriched functions with serine-type endopeptidase activity overrepresented in UC patients. Using a biotinylated fluorophosphonate probe and streptavidin-based enrichment, we show that serine endopeptidases are active in patient fecal samples and that additional putative serine hydrolases are detectable by this approach compared with unenriched profiling. Finally, as metaproteomic databases expand, they are expected to asymptotically approach completeness. Using ComPIL and de novo peptide sequencing, we estimate the size of the probable peptide space unidentified ("dark peptidome") by our large database approach to establish a rough benchmark for database sufficiency. Despite high variability inherent in patient samples, our analysis yielded a catalog of differentially enriched proteins between healthy and UC fecal proteomes. This catalog provides a clinically relevant jumping-off point for further molecular-level studies aimed at identifying the microbial underpinnings of UC.

Recurrent thoracic intramedullary schwannoma: report of two cases with long term follow up.

Occurrence of intramedullary schwannomas is rare as Schwann cells are generally present in the nerve root and not in the spinal cord. To date, approximately around 60 cases of intramedullary schwannoma in patients without neurofibromatosis have been reported in the English literature, of which only eight were children. We describe two cases of thoracic intramedullary schwannomas that recurred after primary excision. A 10 years old boy presented with weakness of both lower limbs. Magnetic resonance imaging showed a D10 to D12 intramedullary lesion, which was excised near totally and confirmed to be a schwannoma on histopathological examination. The tumour recurred twice after that and was re operated both times. Another 57 years old lady presented with weakness of both lower limbs and a history of being operated in the past for D9-D10 intramedullary lesion. She was re-operated with total removal of the lesion confirmed to be schwannoma on histopathological examination. Intramedullary schwannoma may recur after resection.

Pediatric thalamic incidentalomas: an international retrospective multicenter study.

OBJECTIVE: Widespread use of modern neuroimaging has led to a surge in diagnosing pediatric brain incidentalomas. Thalamic lesions have unique characteristics such as deep location, surgical complexity, and proximity to eloquent neuronal structures. Currently, the natural course of incidental thalamic lesions is unknown. Therefore, the authors present their experience in treating such lesions. METHODS: A retrospective, international multicenter study was carried out in 8 tertiary pediatric centers from 5 countries. Patients were included if they had an incidental thalamic lesion suspected of being a tumor and were diagnosed before the age of 20 years. Treatment strategy, imaging characteristics, pathology, and the outcome of operated and unoperated cases were analyzed. RESULTS: Overall, 58 children (23 females and 35 males) with a mean age of 10.8 ± 4.0 years were included. The two most common indications for imaging were nonspecific reasons (n = 19; e.g., research and developmental delay) and headache unrelated to small thalamic lesions (n = 14). Eleven patients (19%) underwent early surgery and 47 were followed, of whom 10 underwent surgery due to radiological changes at a mean of 11.4 ± 9.5 months after diagnosis. Of the 21 patients who underwent surgery, 9 patients underwent resection and 12 underwent biopsy. The two most frequent pathologies were pilocytic astrocytoma and WHO grade II astrocytoma (n = 6 and n = 5, respectively). Three lesions were high-grade gliomas. CONCLUSIONS: The results of this study indicate that pediatric incidental thalamic lesions include both low- and high-grade tumors. Close and long-term radiological follow-up is warranted in patients who do not undergo immediate surgery, as tumor progression may occur.

A general and concise stereodivergent chiral pool approach toward trans-(4S,5R)- and cis-(4R,5R)-5-alkyl-4-methyl-γ-butyrolactones: Syntheses of (+)-trans- and (+)-cis-whisky and cognac lactones from d-(+)-mannitol.

A straightforward synthesis of (+)-trans-(4S,5R)- and (+)-cis-(4R,5R)-whisky lactones starting from d-(+)-mannitol has been reported here in fewer number of efficient steps compared to existing literature processes involving d-mannitol as the chiral pool starting material. Chiron approach directly translated chirality of d-mannitol to one of the two chiral centers in these target molecules. Toward this end, stereoisomerically pure trans- and cis-iodomethyl-γ-lactones were formed in the penultimate step. These two acted as versatile advanced common intermediates as they were also converted to the (+)-trans-(4S,5R)- and (+)-cis-(4R,5R)-cognac lactones, respectively. To the best of our knowledge, till date no synthesis of cognac lactones starting from d-mannitol has been reported. All these lactones are identified as the key aroma components of aged alcoholic beverages.

Emergence of metamagnetic transition, re-entrant cluster glass and spin phonon coupling in Tb2CoMnO6.

The double perovskite compound Tb2CoMnO6has been investigated using x-ray absorption spectroscopy (XAS), Raman spectroscopy, magnetic measurements andab initioband structure calculations. It is observed that both anti-ferromagnetic (AFM) and ferromagnetic (FM) phase coexist in this material. The presence of anti-site disorder (ASD) has been established from the analysis of neutron diffraction data. Moreover, a prominent metamagnetic transition is observed in theM(H) behavior that has been explained with the drastic reorientation of the pinned domain which are aligned antiparallel by the antiphase boundaries (APBs) at zero field. The ASD further gives rise to spin frustration at low temperature which leads to the re-entrant cluster glass ∼33 K. The coupling between phononic degree of freedom and spin in the system has also been demonstrated. It is observed that the theoretical calculation is consistent with that of the experimentally observed behavior.

Defect induced ferromagnetic ordering and room temperature negative magnetoresistance in MoTeP.

The magneto-transport, magnetization and theoretical electronic-structure have been investigated on type-II Weyl semimetallic MoTeP. The ferromagnetic ordering is observed in the studied sample and it has been shown that the observed magnetic ordering is due to the defect states. It has also been demonstrated that the presence of ferromagnetic ordering in effect suppresses the magnetoresistance (MR) significantly. Interestingly, a change-over from positive to negative MR is observed at higher temperature which has been attributed to the dominance of spin scattering suppression.

Amniotic band syndrome associated with limited dorsal myeloschisis: a case report of an unusual case and review of the literature.

Amniotic band syndrome (ABS) has been known since ancient times. Descriptions in modern medicine have occurred since the mid-nineteenth century. The association of the amniotic band syndrome with tethered cord is rare. It was generally thought to be incompatible with life. Of late, with better imaging, there have been case reports of amniotic bands causing cord tethering in neurosurgical literature, but its association with limited dorsal myeloschisis has hitherto not been described. We report a case of amniotic band syndrome (ABS) associated with a cervical limited dorsal myeloschisis (LDM) in a child of 2 and a half years old. The management of LDM in ABS is essentially the same as in isolated cases.

Outcome in 32 cases of tethered cord in adults-is intervention justified?

INTRODUCTION: Adults rarely present with tethered cord syndrome, and this review examines whether it is justifiable to perform surgical intervention in this group. METHODS: Between 2003 and 2017, we performed surgical intervention in 32 adults with tethered cord syndrome. The age range varied from 22 to 65 years. Twenty-six had pain, 20 had motor deficits, and 18 had sensory deficits, whereas 17 presented with sphincter disturbances. Three had undergone surgery for meningomyelocele as infants. Six patients had major spinal deformity in the shape of kyphosis or scoliosis. All patients underwent digital radiographs and MR scans of the whole spine. The oldest with a leaking open meningocele was 41 years old. RESULTS: The mean follow-up was 3.2 years. Twenty-one out of 26 patients presenting with pain had their VAS scores improve significantly; 14 had motor deficits which improved. However, sensory deficits got better in only 7 out of 18 patients, and sphincter improvement was documented (via urodynamics studies and bladder ultrasound) in only 4 out of 17 patients. In 15 cases, surgery was performed under neurophysiological monitoring, and overall improvement was documented in 11 of these patients compared with 7 of the remaining 17 patients. Surgery for spinal deformity was performed in 6 patients, and deformity correction as well as pain reduction was achieved in all. CONCLUSION: Surgery leads to significant reduction of pain by untethering and in those with spinal deformity by correction of the same. Improvement in sensory changes and sphincter problems occurred in few patients. Neuromonitoring certainly has improved our results.