Vincenzo Albanese

Metabotropic glutamate receptor expression in cultured rat astrocytes and human gliomas

In order to confirm the existence of metabotropic glutamate receptors in astroglial cultures and to provide information on different receptor subtypes, the expression of different mOIuRs was analysed in cultures highly enriched in rat astroglial cells. mRNA levels for mGluR1, 2, 3, 4, 7 were undetectable by Northern blot analysis in primary type-1 astroglial cultures derived from total cerebral hemispheres, cerebral cortex and striatum. Interestingly, these cultures expressed a low, but detectable, level of mGluR5 mRNA. The more sensitive technique Reverse Transcription-Polymerase Chain Reaction (RT-PCR) confirmed the presence of mGluR5 transcript in cultured astrocytes and, in addition, revealed the presence of mGluR3 mRNA. The lack of expression of mGluR5 in CG-4 cells, a rat cell line able to differentiate in type-2 astrocytes or oligodendrocytes depending on the culture conditions, suggested that the presence of mGluR5 was not a general feature of cells of glial origin. Moreover, all the examined mGluR transcripts were undetectable by RT-PCR in CG4 cells. In order to confirm the possible expression of mGluR5 in cell of glial origin we examined the mRNA levels for this receptor in tissue samples from human gliomas obtained after surgical resection of the tumors: only 1 sample (grade II astrocytoma), out of 8 examined, showed the presence of mGluR5 mRNA. In conclusion our data show that the only cloned metabotropic receptor linked to phosphoinositide hydrolysis, whose expression is detectable in cultured type-1 astrocytes, is mGluR5. It remains to be established if the low level of expression of mGluR3 could be responsible for the group II metabotropic glutamate receptor activity previously observed in cultured astroglial cells.

A global perspective on the outcomes of surgical decompression in patients with cervical spondylotic myelopathy: results from the prospective multicenter AOSpine international study on 479 patients.

Study Design. Prospective, multicenter international cohort. Objective. To evaluate outcomes of surgical decompression for cervical spondylotic myelopathy (CSM) at a global level. Summary of Background Data. CSM is a degenerative spine disease and the most common cause of spinal cord dysfunction worldwide. Surgery is increasingly recommended as the preferred treatment strategy for CSM to improve neurological and functional status and quality of life. The outcomes of surgical intervention for CSM have never been evaluated at an international level. Methods. Between October 2007 and January 2011, 479 symptomatic patients with image evidence of CSM were enrolled in the prospective, multicenter AOSpine CSM-International study from 16 global sites. Preoperative and postoperative clinical status, functional impairment, and quality of life were evaluated using the modified Japanese Orthopaedic Assessment Scale, Nurick Scale, Neck Disability Index, and Short-Form-36v2. Preoperative and 12- and 24-month postoperative outcomes were compared using mixed-model analysis of covariance for repeated measurements. Results. The study cohort consisted of 310 males and 169 females, with a mean age of 56.37 ± 11.91 years. There were significant differences in age, etiology, and surgical approaches between the regions. At 24 months postoperatively, the mean modified Japanese Orthopaedic Assessment Scale score improved from 12.50 (95% confidence interval [CI], 12.24–12.76) to 14.90 (95% CI, 14.64–15.16); the Neck Disability Index improved from 36.38 (95% CI, 34.33–38.43) to 23.20 (95% CI, 21.24–25.15); and the SF36v2 Physical Component Score and Mental Composite Score improved from 34.28 (95% CI, 33.46–35.10) to 40.76 (95% CI, 39.71–41.81) and 39.45 (95% CI, 38.25–40.64) to 46.24 (95% CI, 44.94–47.55), respectively. The rate of neurological complications was 3.13%. Conclusion. Surgical decompression for CSM is safe and results in improved functional status and quality of life in patients around the world, irrespective of differences in medical systems and sociocultural determinants of health. Level of Evidence: 3

Positioning on surgical table

Positioning on the surgical table is one of the most important steps in any spinal surgical procedure. The “prone position” has traditionally been and remains the most common position used to access the dorsolumbar-sacral spine. Over the years, several authors have focused their attention on the anatomy and pathophysiology of both the vascular system and ventilation in order to reduce the amount of venous bleeding, as well as to prevent other complications and facilitate safe posterior approaches. The present paper reviews the pertinent literature with the aim of highlighting the advantages and disadvantages of various frames and positions currently used in posterior spinal surgery.

AMPA receptor subunits are differentially expressed in parvalbumin- and calretinin-positive neurons of the rat hippocampus

Recent studies suggest a functional diversity of native α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazole propionate‐type glutamate receptor channels (AMPARs). In several types of interneurons, AMPARs are characterized by higher Ca2+ permeability and faster kinetics than AMPARs in principal cells. We studied the expression profile of AMPAR subunits in the hippocampal parvalbumin (PV)‐ and calretinin (CR)‐positive cells, which represent different populations of non‐principal cells. To this end, non‐radioactive in situ hybridization with AMPAR subunit specific cRNAs was combined with immunocytochemistry for PV or CR. Double‐immunolabelling using antibodies against AMPAR subunits and PV or CR was also performed. PV‐containing neurons represent a fairly homogeneous population of cells expressing high levels of GluR‐A and GluR‐D mRNAs, moderate levels of GluR‐C and low levels of GluR‐B mRNAs in all the examined regions of hippocampus. The vast majority of CR‐containing cells have a much lower expression of GluR‐A, ‐C and ‐D mRNA than PV‐positive neurons, although similarly featuring low levels of GluR‐B mRNA. Only a subpopulation of CR‐containing cells, the spiny neurons of the dentate gyrus and CA3 region of the hippocampus were characterized by a strong expression of GluR‐A and ‐D subunit mRNAs. The differential pattern found for the AMPAR subunit mRNA expression was confirmed by immunocytochemistry at protein level. Despite the common feature of low GluR‐B subunit expression, PV‐ and CR‐containing interneurons differ with respect to the density and combination of their expressed AMPAR subunits. The different combination of subunits might subserve different properties of the AMPA channels featured by these cell types, with implications for the functioning of the hippocampal network.

Choroid plexus papilloma of the third ventricle

Choroid plexus papillomas are rarely located in the third ventricle. The case of a 49-year-old man who had a total microsurgical excision of such a lesion is reported. The neuroradiological features and the surgical results are discussed, with a review of 25 other cases reported in the literature. Microsurgical technique made possible a good exposure and successful complete removal of the tumor.

Multiloculated Hydrocephalus in Infants

The clinical features and the neuroradiological appearance of multiloculated hydrocephalus that followed meningitis and ventriculitis in five newborn infants are presented. Several factors probably involved in the pathogenesis are discussed. Computed tomography is particularly helpful in the recognition of this entity and in the evaluation of its course. However, ventriculograms are advised to document the communication of the septated cavities. Of four infants treated by ventriculoatrial shunting, two died and two are mentally and neurologically disabled. Another infant, who underwent craniotomy and fenestration of the ventricular membranes, died accidentally 3 months after operation. In light of similar cases reported in the literature, the prognosis seems very poor. Craniotomy with fenestration of the ventricular septa seems a promising procedure, although further supportive evidence is needed.

Intramedullary spinal cystic teratoma of the conus medullaris with caudal exophytic development: Case report

Spinal intramedullary teratoma is a rare tumor. A case of intramedullary teratoma of the conus medullaris with caudal exophytic development is presented. The patient underwent magnetic resonance imaging and then the tumor was removed surgically. This is the sixth case of intramedullary teratoma reported in the literature.

High levels of connexin 43 mRNA in high grade astrocytomas. Study of 32 cases with in situ hybridization

Gap junctions are composed of a family of evolutionarily conserved integral plasma membrane proteins termed connexins. The aims of the research reported here were (1) to evaluate the Cx43 protein and mRNA of both low histological grade and high histological grade astrocyte tumors; (2) to evaluate if the immunohistochemistry of the Cx43 protein in astrocytomas could be correlated to histological grade, to proliferative activity (Ki67/Mib1-index) and to immunolabelling of the epidermal growth factor receptor (EGFR); (3) to evaluate if the reduction in levels of the Cx43 protein correlates with reduction in levels of the Cx43 mRNA. This study showed that the immunohistochemical labelling of Cx43 is reduced in grade III and grade IV. Decreased gap junction-mediated intercellular communication corresponds to decreased Cx43 and increased cellular proliferation rates, as measured by immunolabelling of the Ki67 nuclear antigen. This study demonstrated also the persistence in high grade astrocytomas of elevated levels of Cx43 mRNA. The reduced levels of Cx43 protein should not to be ascribed to a reduced genetic transcription, but to an alteration of the post-transcriptional mechanisms such as the regulation of its synthesis and/or the intracellular transport to membrane sites.

Lumbar Lateral Interbody Fusion (LLIF): Comparative Effectiveness and Safety versus PLIF/TLIF and Predictive Factors Affecting LLIF Outcome

Study Design Systematic review. Study Rationale The surgical treatment of adult degenerative lumbar conditions remains controversial. Conventional techniques include posterior lumbar interbody fusion (PLIF) or transforaminal lumbar interbody fusion (TLIF). A new direct approach known as lumbar lateral interbody fusion (LLIF), or extreme lateral interbody fusion (XLIF®) or direct lateral interbody fusion (DLIF), has been introduced. Objectives The objective of this article is to determine the comparative effectiveness and safety of LLIF, at one or more levels with or without instrumentation, versus PLIF or TLIF surgery in adults with lumbar degenerative conditions, and to determine which preoperative factors affect patient outcomes following LLIF surgery. Materials and Methods A systematic review of the literature was performed using PubMed and bibliographies of key articles. Articles were reviewed by two independent reviewers based on predetermined inclusion and exclusion criteria. Each article was evaluated using a predefined quality rating scheme. Results The search yielded 258 citations and the following met our inclusion criteria: three retrospective cohort studies (all using historical cohorts) (class of evidence [CoE] III) examining the comparative effectiveness and safety of LLIF/XLIF®/DLIF versus PLIF or TLIF surgery, and one prospective cohort study (CoE II) and two retrospective cohort studies (CoE III) assessing factors affecting patient outcome following LLIF. Patients in the LLIF group experienced less estimated blood loss and a lower mortality risk compared with the PLIF group. The number of levels treated and the preoperative diagnosis were significant predictors of perioperative or early complications in two studies. Conclusion There is insufficient evidence of the comparative effectiveness of LLIF versus PLIF/TLIF surgery. There is low-quality evidence suggesting that LLIF surgery results in fewer complications or reoperations than PLIF/TLIF surgery. And there is insufficient evidence that any preoperative factors exist that predict patient outcome after LLIF surgery.

The "sandwich phenomenon": a rare complication in adjacent, double-level X-stop surgery: report of three cases and review of the literature.

Study Design. Case reports. Objective. To report the atraumatic fracture of the intervening (L4) spinous process (SP) in patients treated with X-Stop at 2 adjacent levels and discuss the potential underlying causes. Summary of Background Data. Limited evidence on complications in double-level X-Stop surgery is available. Methods. Three men, 47, 63, and 75 years old, respectively, underwent surgery with insertion of X-Stop at L3–L4 and L4–L5 because of low back pain and neurogenic claudication due to degenerative lumbar spine conditions. Two 10 mm devices were implanted in the first patient and two 16 mm distractors in the second man. One 10 mm X-Stop at L3–L4 and one 12 mm at L4–L5, respectively, were implanted in the third patient. No intraoperative complications occurred and the postoperative course was uneventful, with symptoms relief. Results. The first 2 patients presented because of recurrent symptoms 4 and 6 months after surgery, respectively. Imaging revealed “spontaneous” fracture of the L4 SP in both of them. Revision surgery was required, with removal of the interspinous devices, decompression and fixation. In the third patient the L4 SP fracture was detected when the patient presented because of recurrent back pain 18 months after the index surgery, but revision surgery was not consented. Conclusion. To our knowledge this is the first report describing the “sandwich phenomenon,” i.e., the atraumatic fracture of the intervening SP in patients with adjacent, double-level X-Stop. Possible underlying theories and anatomic peculiarities which may predispose to this rare event are discussed.