Sergei Spektor

Gliomas display a microRNA expression profile reminiscent of neural precursor cells

Gliomas express many genes that play a role in neural precursor cells (NPCs), but no direct comparison between glioma and stem cell (SC) gene expression profiles has been performed. To investigate the similarities and differences between gliomas and SCs, we compared the microRNA (miRNA) expression signatures of glial tumors, embryonic SCs (ESCs), NPCs, and normal adult brains from both human and mouse tissues. We demonstrated that both human gliomas (regardless of their grade) and methylcholanthrene-induced mouse glioma shared an miRNA expression profile that is reminiscent of NPCs. About half of the miRNAs expressed in the shared profile clustered in seven genomic regions susceptible to genetic/epigenetic alterations in various cancers. These clusters comprised the miR17 family, mir183-182, and the SC-specific clusters mir367-302 and mir371-373, which are upregulated in gliomas, ESCs, and NPCs. The bipartite cluster of 7 + 46 miRNAs on chromosome 14q32.31, which might represent the largest tumor suppressor miRNA cluster, was downregulated in the shared expression profile. This study provides the first evidence for association between these clusters and gliomas. Despite the broad similarity in the miRNA expression profiles, 15 miRNAs showed disparate expression between SC and gliomas. Ten miRNAs belong to the 2 SC-specific clusters and the remaining (mir135b, mir141, mir205, mir200C, and mir301a) have been previously shown to associate with malignancies. Our finding showed that all gliomas displayed NPC-like miRNA signatures, which may have implications for studies of glioma origins. Furthermore, careful study of the 15 miRNAs that differ in expression between SCs and gliomas, particularly those 5 that are not SC-specific, may enhance our understanding of gliomagenesis.

The role of hair shaving in skull base surgery.

OBJECTIVE: We sought to evaluate surgical wound infection rates in patients undergoing skull base surgery without hair removal. METHODS: We undertook a retrospective study of 175 skull base operations performed without hair removal. Anterior operations were conducted via the subcranial approach (n = 120) and lateral or posterior procedures via various approaches (n = 55). Wounds were examined daily during hospitalization and at routine outpatient follow-up (8 to 45 months) and classified according to the Center for Disease Control and Prevention guidelines. RESULTS: The overall surgical wound infection rate was 1.1% (2 of 175): 0.8% (1 of 120) for anterior and 1.8% (1 of 55) for lateral or posterior procedures. It was similar for clean operations (lateral and posterior) and clean-contaminated (anterior) procedures and was less than or similar to the rates reported for skull base procedures with hair removal. No wound infection occurred among the infected (trauma, fungal infections, and brain abscess) patients. CONCLUSIONS: Skull base surgery without hair removal is safe and not associated with increased risk of wound infection. The method may prevent additional psychologic stress, promote restoration of the patients self-image, and accelerate his or her return to normal life.

Anterior skull base surgery without prophylactic airway diversion procedures

OBJECTIVE Although anterior skull base surgery has become a relatively safe and effective procedure, postoperative complications remain a serious problem. One of the most devastating complications of anterior skull base procedures is tension pneumocephalus (TP). In order to prevent TP, authors have recommended the use of prophylactic airway diversion procedures, such as prolonged endotracheal intubation or prophylactic tracheostomy. However, these procedures may mask neurologic deterioration, delay treatment, and prolong rehabilitation. The purpose of this study was to determine the need for airway diversion procedures in anterior skull base surgery. STUDY DESIGN Eighty-five patients underwent anterior skull base operations through the subcranial approach without prophylactic airway diversion. Sixty-four patients underwent resection of tumors, 12 patients underwent repair of cerebrospinal fluid leak, 6 patients underwent surgery due to anterior skull base fungal infections, and 3 patients underwent anterior skull base reconstruction procedures. RESULTS The complication rate of TP was 1.2% (1/85). This complication rate is similar to that previously reported for operations performed with airway diversion procedures. CONCLUSION Prophylactic airway diversion procedures are unnecessary in routine anterior skull base operations. Airway diversion should be indicated only when factors that might predispose the patient to risk of TP have been identified (ie, chronic cough or obstructive pulmonary diseases).

Cyst Wall Enhancement in Pilocytic Astrocytoma: Neoplastic or Reactive Phenomena

Cystic pilocytic astrocytomas (CPA) consist of a mural nodule and an accompanying cyst, which may prominently enhance on MRI after contrast administration. This raises the question whether an enhanced wall represents a tumor and thus should be resected together with the solid nodule, as radical tumor surgery is associated with better prognosis. Until now, no systematic histopathological examinations of cyst walls have been reported in correlation with MRI, intraoperative appearance and postoperative clinical and MRI follow-up. We present 3 patients with CPAs and brightly enhanced cyst walls on MRI. Because of the benign, transparent appearance of the cyst wall intraoperatively, it was biopsied but not resected, and only radical removal of the nodule and its immediate surroundings was performed. Separate specimens taken from the cyst wall showed no tumor. MRI performed annually, up to 48–56 months after surgery showed no recurrence of the cyst or the tumor. In such cases of CPA, we suggest that enhancement of cyst walls may represent reactive rather than tumoral tissue, and may be left intact without risking worse prognosis. Mechanisms leading to cyst wall enhancement and the optimal surgical treatment are discussed.

Rathke’s Cleft Cyst Abscess

Pituitary abscesses are rare. Occasionally they will arise in pre-existing pituitary pathology. We report such an occurrence within a Rathke’s cleft cyst. On the basis of history and imaging, this was indistinguishable from more commonly encountered pituitary pathology.

Epidural hematoma in infants: a different entity?

BACKGROUND Epidural hematoma (EDH) in infants may be difficult to diagnose. The mechanism of injury and the clinical presentation are different from those in older children. We characterized the clinical and radiologic parameters of EDH in infants and correlated them with outcome. Because there are no optimal prognostic tools or clear guidelines to perform computed tomography in this unique population, a new approach of neurotrauma scoring is suggested. METHODS Eleven infants (<2 years old) operated on for EDH were studied. Childrens Glasgow Coma Scale (CCS) score was applied, and diagnosis was confirmed by computed tomography. RESULTS Age was 13+/-5 months. Seven infants (63.6%) fell from less than 1 m. CCS score on admission was 10.7+/-3.9. Five infants (45%) were unconscious, yet two (18.2%) had CCS scores of 15. Pupillary abnormalities were found in two infants and lateralizing signs in five infants. Eight infants (72.7%) had subgaleal hematomas. Mortality and morbidity were 9% each. CONCLUSION We suggest that a Trauma Infant Neurologic Score be used when dealing with EDH in infants. Lateralizing signs, pupillary abnormalities, mechanism of trauma, and scalp injuries should be included because these are objective relevant parameters.

Syndrome of Overdrainage Associated with Disconnection of a Ventriculoperitoneal Shunt

We present the case of a child who developed the syndrome of cerebrospinal fluid (CSF) overdrainage with slit-like ventricles on CT in the setting of a disconnected distal shunt valve. Upgrading the shunt alleviated his symptoms. It is suggested that the presence of a patent fibrous tract allowed the overdrainage of CSF.