Spinal cord injury: Current trends in acute management.

Introduction: Traumatic spinal cord injury (tSCI) is a profoundly debilitating condition necessitating prompt intervention. However, the optimal acute treatment strategy remains a subject of debate. Research question: The aim of this overview is to elucidate prevailing trends in the acute tSCI management. Material and Methods: We provided an overview using peer-reviewed studies. Results: Early surgical treatment (<24h after trauma) appears beneficial compared to delayed surgery. Nonetheless, there is insufficient evidence supporting a positive influence of ultra-early surgery on neurological outcome in tSCI. Furthermore, the optimal surgical approach to decompress the spinal cord remains unclear. These uncertainties extend to a growing aging population suffering from central cord syndrome (CCS). Additionally, there is a paucity of evidence supporting the beneficial effects of strict hemodynamic management. Discussion and Conclusion: This overview highlights the current literature on surgical timing, surgical techniques and hemodynamic management during the acute phase of tSCI. It also delves into considerations specific to the elderly population experiencing CCS.

Early ultrasonographic detection of low-volume intraneural injection.

BACKGROUND: Intraneural injection of local anaesthetic agents carries a risk of neurological complications. Early detection of intraneural needle-tip position is very important in the initial phase of injection. Ultrasound (US) characteristics for real-time detection of intraneural injections have been described, but only for relatively large volumes (5-40 ml). This study assesses the reliability of various US criteria to detect early low volume (0.5 ml) intraneural injections. Intraneural deposition of an injected dye was confirmed by cryomicrotomy. METHODS: In nine unembalmed human cadavers, 0.5 ml methylene blue was injected intraneurally into the supraclavicular brachial plexus and subgluteal sciatic nerve on both sides. The sites of injection were subsequently removed en bloc. Consecutive cryomicrotomy cross-sections with a 50 µm interval were obtained to assess intraneural presence of the injectate. Two independent experts separately reviewed US video clips of the injections and scored each US criterion. RESULTS: Of the 36 injections, cryomicrotome cross-sections showed intraneural staining in 33 and extraneural staining in three. The best US criterion was expansion of the nerve cross-sectional surface area together with a change in echogenicity. It was observed in 35 injections, including two false positives. There was one true negative. Test precision was 94% [95% confidence interval (CI), 87-100%]. The mean increase in surface area was 8.7% (95% CI, 5.6-11.9). CONCLUSIONS: Reliable detection of early low-volume intraneural injection using US is possible using expansion of the cross-sectional surface area of the nerve together with a change in echogenicity as markers.

Soft tissue landmark for ultrasound identification of the sciatic nerve in the infragluteal region: the tendon of the long head of the biceps femoris muscle.

BACKGROUND AND OBJECTIVES: The sciatic nerve block represents one of the more difficult ultrasound-guided nerve blocks. Easy and reliable internal ultrasound landmarks would be helpful for localization of the sciatic nerve. Earlier, during ultrasound-guided posterior approaches to the infragluteal sciatic nerve, the authors recognized a hyperechoic structure at the medial border of the long head of biceps femoris muscle (BFL). The present study was performed to determine whether this is a potential internal landmark to identify the infragluteal sciatic nerve. METHODS: The depth and the thickness of this hyperechoic structure, its relationship with the sciatic nerve and the ultrasound visibility of both were recorded in the proximal upper leg of 21 adult volunteers using a linear ultrasound probe in the range of 7-13 MHz. The findings were verified by an anatomical study in two cadavers. RESULTS: The hyperechoic structure at the medial border of the BFL extended in a dorsoventral direction between 1.4+/-0.6 cm (mean+/-SD) and 2.8+/-0.8 cm deep from the surface, with a width of 2.2+/-0.9 mm. Between 2.6+/-0.9 and 10.0+/-1.5 cm distal to the subgluteal fold, the sciatic nerve was consistently identified directly at the ventral end of the hyperechoic structure in all volunteers. The anatomical study revealed that this hyperechoic structure corresponds to tendinous fibres inside and at the medial border of the BFL. CONCLUSION: The hyperechoic BFL tendon might be a reliable soft tissue landmark for ultrasound localization of the infragluteal sciatic nerve.

Neurotrophin dependence domain: a domain required for the mediation of apoptosis by the p75 neurotrophin receptor.

The mechanisms underlying neurotrophin dependence, and cellular dependent states in general, are unknown. We show that a 29 amino acid region in the intracellular domain of the common neurotrophin receptor, p75NTR, is required for the mediation of apoptosis by p75NTR. Furthermore, contrary to results obtained with Fas, monomeric p75NTR is required for apoptosis induction, whereas multimerization inhibits the pro-apoptotic effect. Within the 29-residue domain required for apoptosis induction by p75NTR, a 14-residue region is sufficient as a peptide inducer of apoptosis. This 14-residue peptide requires the positively charged carboxyterminal residues for its effect on cell death, and these same residues are required by the full-length p75NTR. These studies define a novel type of domain that mediates neurotrophin dependence, and suggest that other cellular dependent states may be mediated by proteins displaying similar domains.

Long-term mortality after transsphenoidal surgery and adjunctive therapy for acromegaly.

To analyze the long term outcome after multimodality therapy for acromegaly, a retrospective review was performed on 162 patients who underwent transsphenoidal surgery at Massachusetts General Hospital between 1978 and 1996. The surgical cure rate for microadenomas was 91%, that for macroadenomas was 48%, and it was 57% overall. The surgical cure rate was significantly dependent on tumor size, but was not dependent on age or sex. An improvement in the surgical cure rate was noted over the course of the review, from 45% before 1987 to 73% since 1991. Long term follow-up was obtained in 99% of U.S. residents (149 of 151), with a mean follow-up period of 7.8 yr. Adjuvant radiation and/or pharmacological therapy was given to 61 patients. Of the entire group, 83% (124 of 149) were in biochemical remission as determined by normalization of serum insulin-like growth factor I levels or by GH suppression after oral glucose tolerance testing at last contact or at death. The recurrence rate was 6% at 10 yr and 10% at 15 yr after surgery in those patients who initially met the criteria for surgical cure. The 10-yr survival rate was 88%, and there were 12 deaths at postoperative intervals of 2-12 yr, with the most common cause of death being cardiovascular disease. A Cox proportional hazards model showed that patient-years with persistent disease carried a 3.5-fold [95% confidence interval (CI), 1.0-12; P = 0.02] relative mortality risk compared to those patient-years in remission. A Poisson person-years regression analysis showed no significant difference in survival between those 86 patients cured at operation and an age- and sex-matched sample from the U.S. population [standardized mortality ratio (SMR), 0.84; 95% CI, 0.3-2.2; P = 0.35]. A similar analysis on the entire group of 149 patients showed no significant difference in survival from that in a control sample (SMR, 1.16; 95% CI, 0.66-2.0; P = 0.3). Mortality risk for patient-years with persistent active disease after unsuccessful treatment vs. that in the U.S. population sample remained increased (SMR, 1.8; 95% CI, 0.9-3.6; P = .05). This analysis suggests that the decreased survival previously reported to be associated with acromegaly can be normalized by successful surgical and adjunctive therapy.

Spinal dural enhancement on magnetic resonance imaging associated with spontaneous intracranial hypotension. Report of three cases and review of the literature.

This report offers a description of typical changes seen on gadolinium-enhanced magnetic resonance (MR) imaging of the entire spine that indicate spontaneous intracranial hypotension (SIH). To the authors' knowledge, this is the first report of its kind. They describe three cases of SIH that were accompanied by dural enhancement throughout the neuraxis on imaging, with the evolution of associated subdural and epidural fluid collections in the spine. Recognition of this disorder is important to be able to distinguish it from an infectious or neoplastic process in which surgical intervention might be warranted. Evaluation using gadolinium-enhanced cranial and spinal MR imaging in patients with postural headaches and an (111)In-labeled cerebrospinal fluid leak study are discussed. Treatment with an epidural blood patch is shown to be particularly effective, with resolution of the radiological and clinical findings.

Leukemia inhibitory factor is expressed in astrocytes following cortical brain injury.

The neuropoietic cytokine leukemia inhibitory factor (LIF) can act as a trophic factor, enhancing neuronal survival, and as a differentiation factor altering neuronal and glial gene expression. LIF also plays a role in the response to injury of the peripheral nervous system, as indicated by an increase in the amount of its mRNA within nonneuronal injury response in LIF knock-out mice. To determine if LIF is regulated after injury to the central nervous system, we surgically lesioned the cortex in adult rat brain. Using a quantitative RNAse protection assay, we find that LIF mRNA increases 30-fold following injury. The amount of this transcript goes up within 6 h after injury, reaches a peak at 24 h and returns to baseline by 7 days postlesion. In situ hybridization analysis reveals LIF transcript-containing cells scattered throughout the ipsilateral cortex close, but not immediately adjacent to the lesion site. Double-labeling with a variety of antibodies reveals that LIF mRNA is induced in GFAP-positive astrocytes as well as in a small number of microglial cells. The striking induction of LIF transcripts in glia suggests that this cytokine may play a key injury-response role in the CNS as it does in the PNS, where LIF has been demonstrated to regulate neuropeptide expression both in vivo and in vitro.

Appearance of a cavernous hemangioma in the cerebral cortex after a biopsy of a deeper lesion.

Cavernous hemangiomas are vascular malformations that can occur throughout the central nervous system. In certain patients, multiple lesions are known to occur. We present a patient with multiple cavernous hemangiomas who had a computed tomography-guided biopsy of a deep parieto-occipital lesion through a burr hole. Several passes of a biopsy needle were used. During a 5-year interval, the patient developed a new lesion directly under the burr hole on the cortical surface. The new lesion appears to have occurred from the implantation and growth of a cavernous hemangioma secondary to the biopsy.

Efficacy of a Proteus mirabilis outer membrane protein vaccine in preventing experimental Proteus pyelonephritis in a BALB/c mouse model.

A BALB/c mouse model of nonobstructive, ascending Proteus mirabilis pyelonephritis was characterized bacteriologically, histologically, and serologically from 3 to 28 days. Intravesicular administration of 2 X 10(8) P. mirabilis K7 resulted in the septic death of 9 (16%) of 57 mice by day 15. Among the survivors, K7 colonized the kidneys in great numbers until day 21. Histological examination of the kidneys revealed acute inflammation which was characterized by neutrophil infiltration by day 3, renal necrosis by day 7, and fibroblastic infiltration by day 14 which persisted at least until day 28. The immunoglobulin G response to the outer membrane proteins (OMP) was assessed by enzyme-linked immunosorbent assay and Western blotting (immunoblotting). Anti-OMP immunoglobulin G antibodies were detected as early as day 7, and the reciprocals of their titers rose progressively up to day 28 (i.e., greater than or equal to 500). This model was also used to assess the efficacy of OMP and lipopolysaccharide (LPS) immunization in preventing renal infection. K7 OMP or LPS (100 micrograms) preparations were administered intramuscularly in Freund's complete adjuvant. After 2 weeks, mice were intravesicularly challenged with 2 X 10(8) bacteria of the homologous K7 strain or one of four heterologous strains. Compared with the saline-immunized control group and K7 LPS-immunized mice, K7 OMP recipients were protected from death when challenged by homologous or heterologous strains. In addition, K7 OMP recipients were protected (P less than 0.003) from subsequent renal infection when challenged by the K7 strain and had more rapid bacterial renal clearance when challenged by three of four heterologous strains. OMP recipients produced antibodies which bound major OMP moieties (viz., 36- to 39-kDa cell wall constituents) as assessed by Western blotting. These results support the concept that immunization with selected bacterial protein surface coat constituents can prevent uromucosal infection by interfering with colonization or renal injury.

Aggregates of acetylcholinesterase induced by acetylcholine receptor-aggregating factor.

Basal lamina-rich extracts of Torpedo californica electric organ contain a factor that causes acetylcholine receptors (AChRs) on cultured myotubes to aggregate into patches. Our previous studies have indicated that the active component of these extracts is similar to the molecules in the basal lamina which direct the aggregation of AChRs in the muscle fibre plasma membrane at regenerating neuromuscular junctions in vivo. Because it can be obtained in large amounts and assayed in controlled conditions in cell culture, the AChR-aggregating factor from electric organ may be especially useful for examining in detail how the postsynaptic apparatus of regenerating muscle is assembled. Here we demonstrate that the electric organ factor causes not only the formation of AChR aggregates on cultured myotubes, but also the formation of patches of acetylcholinesterase (AChE). This finding, together with the observation that basal lamina directs the formation of both AChR and AChE aggregates at regenerating neuromuscular junctions in vivo, leads us to hypothesize that a single component of the synaptic basal lamina causes the formation of both these synaptic specializations on regenerating myofibres.