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Study Design: A single-institution, retrospective cohort study., Objective: The objective was to present demographic characteristics, mechanism of injuries, lengths of stay, intensive care unit (ICU) days, discharge locations, and causes of 90-day readmission for patients with subaxial spinal cord injuries resulting in paraplegia or tetraplegia., Summary of Background Data: Spinal cord injuries resulting in paraplegia or tetraplegia are rare injuries with debilitating outcomes. Numerous advances have occurred in caring for these patients, but patients still experience multiple complications. The severity of these injuries and numerous complications result in prolonged hospital stays and the need for extensive rehabilitation., Methods: Twelve patients with subaxial spinal cord injury resulting in paraplegia or tetraplegia from a level 1 adult trauma center were reviewed. The primary outcomes included hospital length of stay, ICU days, intrahospital complications, 90-day readmission rates, and discharge location. We reviewed the literature for these outcomes in spinal cord injuries., Results: For patients with subaxial spinal cord injuries resulting in paraplegia and tetraplegia, the average age was 36.0 years, and most were male [91.7% (11/12)]. The most common mechanism of injury was gunshot wounds[41.7% (5/12)]. Patients spent an average of 46.3 days in the hospital and 30.7 days in the ICU. Respiratory complications were the most common (9 patients). Fifty percent of patients (6/12) were discharged to the inpatient spinal cord rehab center, and 16.7% (2/12) expired while in the hospital. Two patients (20.0%) were readmitted within 90 days of discharge., Conclusions: Most patients with subaxial spinal cord injuries resulting in paraplegia or tetraplegia were young males with high-energy traumas. Many patients had intrahospital complications, and most were discharged to the hospital spinal rehab center. These findings likely stem from the severity of paraplegia and tetraplegia injuries and the need for rehabilitation., Competing Interests: The authors declare no conflict of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Introduction: With the increasing use of the internet for health information, it is essential to prioritize resources that match the reading level of patients and parents. Limited health literacy is a notable issue in the United States, creating a financial burden and negatively affecting patient outcomes. This study aimed to assess the availability and readability of pediatric hospital web pages concerning two prevalent spine conditions in children, spondylolisthesis and spondylolysis, specifically examining whether the available resources meet the recommended sixth grade reading level., Methods: A total of 179 pediatric hospital web pages were assessed for their availability and readability of spondylolisthesis and spondylolysis patient information. The web pages' readability was assessed using five readability formulae. Descriptive statistics and Student t-tests were performed on the collected scores with significance set at P < 0.05., Results: Among the analyzed hospitals, 40.2% had no information on spondylolisthesis or spondylolysis, 20.1% mentioned treating these conditions, 7.8% had < 100 dedicated words, and only 31.8% had dedicated web pages with more than 100 words on these conditions. The average reading grade level for the evaluated web pages was 12.0, indicating a high school education level is required for comprehension. None of the web pages were written below the recommended sixth grade reading level., Discussion: The readability of the limited resources was markedly higher than the recommended reading level. In addition, this study emphasizes the need for enhanced accessibility and readability of online patient information from pediatric hospitals to improve parental comprehension and informed decision-making. Physicians should consider identifying online resources that they consider of high quality and acceptable readability to support better patient understanding and outcomes., (Copyright © 2023 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Orthopaedic Surgeons.)

Background: Thoracolumbar fractures (TLFs) are the most common spinal fractures seen in patients with trauma. The Thoracolumbar Injury Classification and Severity (TLICS) classification system is commonly used to help clinicians make more consistent and objective decisions in assessing the indications for surgical intervention in patients with thoracolumbar fractures. Patients with TLICS scores <4 are treated conservatively, but a percentage of them will have failed conservative treatment and require surgery at a later date., Methods: All patients who received an orthopaedic consult between January 2016 and December 2020 were screened for inclusion and exclusion criteria. For patients meeting the study requirements, deidentified data were collected including demographics, diagnostics workup, and hospital course. Data analysis was conducted comparing length of stay, time between first consult and surgery, and time between surgery and discharge among each group., Results: 1.4% of patients with a TLICS score <4 not treated surgically at initial hospital stay required surgery at a later date. Patients with a TLICS score <4 treated conservatively had a statistically significant shorter hospital stay compared with those treated surgically. However, when time between initial consult and surgery was factored into the total duration of hospital stay for those treated surgically, the duration was statistically equivalent to those treated nonsurgically., Conclusion: For patients with a TLICS score <4 with delayed mobilization after 3 days in the hospital or polytraumatic injuries, surgical stabilization at initial presentation can decrease the percentage of patients who fail conservative care and require delayed surgery. Patients treated surgically have a longer length of stay than those treated conservatively, but there is no difference in stay when time between consult and surgery was accounted for. In addition, initial surgery in patients with delayed mobilization can prevent long waits to surgery, while conservative measures are exhausted., Level Iii Evidence: Retrospective cohort study., (Copyright © 2023 by the American Academy of Orthopaedic Surgeons.)

Experimental data about gene functions curated from the primary literature have enormous value for research scientists in understanding biology. Using the Gene Ontology (GO), manual curation by experts has provided an important resource for studying gene function, especially within model organisms. Unprecedented expansion of the scientific literature and validation of the predicted proteins have increased both data value and the challenges of keeping pace. Capturing literature-based functional annotations is limited by the ability of biocurators to handle the massive and rapidly growing scientific literature. Within the community-oriented wiki framework for GO annotation called the Gene Ontology Normal Usage Tracking System (GONUTS), we describe an approach to expand biocuration through crowdsourcing with undergraduates. This multiplies the number of high-quality annotations in international databases, enriches our coverage of the literature on normal gene function, and pushes the field in new directions. From an intercollegiate competition judged by experienced biocurators, Community Assessment of Community Annotation with Ontologies (CACAO), we have contributed nearly 5,000 literature-based annotations. Many of those annotations are to organisms not currently well-represented within GO. Over a 10-year history, our community contributors have spurred changes to the ontology not traditionally covered by professional biocurators. The CACAO principle of relying on community members to participate in and shape the future of biocuration in GO is a powerful and scalable model used to promote the scientific enterprise. It also provides undergraduate students with a unique and enriching introduction to critical reading of primary literature and acquisition of marketable skills., Competing Interests: The authors have declared that no competing interests exist.

Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) provides a unique in situ chemical profile that can include drugs, nucleic acids, metabolites, lipids, and proteins. MSI of individual cells (of a known cell type) affords a unique insight into normal and disease-related processes and is a prerequisite for combining the results of MSI and other single-cell modalities (e.g. mass cytometry and next-generation sequencing). Technological barriers have prevented the high-throughput assignment of MSI spectra from solid tissue preparations to their cell type. These barriers include obtaining a suitable cell-identifying image (e.g. immunohistochemistry) and obtaining sufficiently accurate registration of the cell-identifying and MALDI-MS images. This study introduces a technique that overcame these barriers by assigning cell type directly from mass spectra. We hypothesized that, in MSI from mice with a defined fluorescent protein expression pattern, the fluorescent protein's molecular ion could be used to identify cell cohorts. A method was developed for the purification of enhanced yellow fluorescent protein (EYFP) from mice. To determine EYFP's molecular mass for MSI studies, we performed intact mass analysis and characterized the protein's primary structure and post-translational modifications through various techniques. MALDI-MSI methods were developed to enhance the detection of EYFP in situ, and by extraction of EYFP's molecular ion from MALDI-MS images, automated, whole-image assignment of cell cohorts was achieved. This method was validated using a well-characterized mouse line that expresses EYFP in motor and sensory neurons and should be applicable to hundreds of commercially available mice (and other animal) strains comprising a multitude of cell-specific fluorescent labels.

Indications for elbow arthroscopy are expanding; however, it is uncommon compared with shoulder arthroscopy. Elbow arthroscopy can be complicated by positioning, including the need to obtain specific arm holders required by most operating rooms. Surgery can be performed in the supine, prone, or lateral position. Arm traction allows for distraction of the joint space, full insufflation, and therefore visualization of intra-articular anatomy. This article outlines a new technique using previously available shoulder arthroscopy equipment to avoid increased cost incurred by procuring new, elbow-specific equipment. This technique is performed in the supine position using a hydraulic system and a shoulder 3-point distractor. [Orthopedics. 2018; 41(1):e158-e160.]., (Copyright 2017, SLACK Incorporated.)

Objective: The authors describe a modified technique for placement of the C1 lateral mass screw using a Steinmann pin as a guide. This technique minimizes dissection and provides atlantoaxial stabilization during arthrodesis., Methods: In our technique, a nonthreaded 1.6-mm spade-tip Steinmann pin is placed into the lateral mass of C1 to serve as a guide over which a powered drill is used for screw insertion. Perioperative data were collected for consecutive patients who underwent a C1-2 arthrodesis that involved the modified technique between March 2010 and July 2016. Data included blood loss, operative times, and C2 nerve root injury., Results: The data for 93 patients were reviewed. Most (91.4%) patients presented with a fracture from an acute trauma. A mean of 1.97 levels was fused in these patients, with a mean blood loss of 76 mL and a mean operative time of 144 minutes. The overall morbidity and mortality rate was 10.7%. The morbidity rate of 7.5% included 30-day postoperative complications of respiratory failure and dysphasia. There were no postoperative vertebral artery injuries, hardware failures, or instances of occipital neuralgia., Conclusions: The use of Steinmann pins to guide the placement of C1 lateral mass screws is safe and effective in C1-2 arthrodesis. Limiting dissection minimizes blood loss and injury, maintains efficient operative time, and assists in accurate placement of the screws. Furthermore, with less manipulation and retraction of the C2 nerve root, postoperative occipital neuralgia and the need for C2 root transection are avoided., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Control of the agitated patient in the emergency department is challenging. Many options exist for chemical sedation, but most have suboptimal pharmacodynamic action, and many have undesirable adverse effects. There are reports of ketamine administration for control of agitation prehospital and in traumatically injured patients. Ketamine is a noncompetitive N-methyl-D-aspartic acid receptor antagonist, making it an effective dissociative agent. We present 5 cases of ketamine administration to manage agitated adolescent patients with underlying psychiatric disease and/or drug intoxication. Ketamine, as a dissociative agent, may be an alternative pharmacological consideration for the control of agitation in patients with undifferentiated agitated delirium.

Imaging mass spectrometry (IMS) is a novel quantitative technique used to investigative diverse biomolecules in tissue sections. Specifically, IMS uses analytical separation of mass spectrometry to determine the spatial distribution of certain lipids and/or proteins located directly on biological sections from a single tissue sample. Typically, IMS is combined with histological analysis to reveal additional distribution details of characterized biomolecules including cell type and/or subcellular localization. In this chapter, we describe the use of Matrix-Assisted Laser Desorption/Ionization (MALDI) Time-Of-Flight/Time-Of-Flight (TOF/TOF) to analyze various cholesterol and phosphatidylcholine species in atherosclerotic plaque of murine heart aortic valves. In particular, we detail animals used, tissue collection, preparation, matrix application, spectra acquisition for generating a color-coded image based on IMS spectral characteristics.

Copper has many roles in biology that involve the change of coordination sphere and/or oxidation state of the copper ion. Consequently, the study of copper in heterogeneous environments is an important area in biophysics. EPR is a primary technique for the investigation of paramagnetic copper, which is usually the isolated Cu(II) ion, but sometimes as Cu(II) in different oxidation states of multitransition ion clusters. The gross geometry of the coordination environment of Cu(II) can often be determined from a simple inspection of the EPR spectrum, recorded in the traditional X-band frequency range (9-10 GHz). Identification and quantitation of the coordinating ligand atoms, however, is not so straightforward. In particular, analysis of the superhyperfine structure on the EPR spectrum, to determine the number of coordinated nitrogen atoms, is fraught with difficulty at X-band, despite the observation that the overwhelming number of EPR studies of Cu(II) in the literature have been carried out at X-band. Greater reliability has been demonstrated at S-band (3-4 GHz), using the low-field parallel (gz) features. However, analysis relies on clear identification of the outermost superhyperfine line, which has the lowest intensity of all the spectral features. Computer simulations have subsequently indicated that the much more intense perpendicular region of the spectrum can be reliably interpreted at L-band (2 GHz). The present work describes the development of L-band EPR of Cu(II) into a routine method that is applicable to biological samples., (© 2015 Elsevier Inc. All rights reserved.)

Non-adiabatic rapid sweep (NARS) EPR spectroscopy has been introduced for application to nitroxide-labeled biological samples (Kittell et al., 2011). Displays are pure absorption, and are built up by acquiring data in spectral segments that are concatenated. In this paper we extend the method to frozen solutions of copper-imidazole, a square planar copper complex with four in-plane nitrogen ligands. Pure absorption spectra are created from concatenation of 170 5-gauss segments spanning 850 G at 1.9 GHz. These spectra, however, are not directly useful since nitrogen superhyperfine couplings are barely visible. Application of the moving difference (MDIFF) algorithm to the digitized NARS pure absorption spectrum is used to produce spectra that are analogous to the first harmonic EPR. The signal intensity is about four times higher than when using conventional 100 kHz field modulation, depending on line shape. MDIFF not only filters the spectrum, but also the noise, resulting in further improvement of the SNR for the same signal acquisition time. The MDIFF amplitude can be optimized retrospectively, different spectral regions can be examined at different amplitudes, and an amplitude can be used that is substantially greater than the upper limit of the field modulation amplitude of a conventional EPR spectrometer, which improves the signal-to-noise ratio of broad lines., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Brain atlases are important tools of neuroscience. Traditionally prepared in paper book format, more and more commonly they take digital form which extends their utility. To simplify work with different atlases, to lay the ground for developing universal tools which could abstract from the origin of the atlas, efforts are being made to provide common interfaces to these atlases. 3D Brain Atlas Reconstructor service (3dBARs) described here is a repository of digital representations of different brain atlases in CAF format which we recently proposed and a repository of 3D models of brain structures. A graphical front-end is provided for creating and viewing the reconstructed models as well as the underlying 2D atlas data. An application programming interface (API) facilitates programmatic access to the service contents from other websites. From a typical user's point of view, 3dBARs offers an accessible way to mine publicly available atlasing data with a convenient browser based interface, without the need to install extra software. For a developer of services related to brain atlases, 3dBARs supplies mechanisms for enhancing functionality of other software. The policy of the service is to accept new datasets as delivered by interested parties and we work with the researchers who obtain original data to make them available to the neuroscience community at large. The functionality offered by the 3dBARs situates it at the core of present and future general atlasing services tying it strongly to the global atlasing neuroinformatics infrastructure.

Cu(II) is an essential element for life but is also associated with numerous and serious medical conditions, particularly neurodegeneration. Structural modeling of crystallization-resistant biological Cu(II) species relies on detailed spectroscopic analysis. Electron paramagnetic resonance (EPR) can, in principle, provide spin hamiltonian parameters that contain information on the geometry and ligand atom complement of Cu(II). Unfortunately, EPR spectra of Cu(II) recorded at the traditional X-band frequency are complicated by (i) strains in the region of the spectrum corresponding to the g(∥) orientation and (ii) potentially very many overlapping transitions in the g(⊥) region. The rapid progress of density functional theory computation as a means to correlate EPR and structure, and the increasing need to study Cu(II) associated with biomolecules in more biologically and biomedically relevant environments such as cells and tissue, have spurred the development of a technique for the extraction of a more complete set of spin hamiltonian parameters that is relatively straightforward and widely applicable. EPR at L-band (1-2 GHz) provides much enhanced spectral resolution and straightforward analysis via computer simulation methods. Herein, the anisotropic spin hamiltonian parameters and the nitrogen coordination numbers for two hitherto incompletely characterized Cu(II)-bound species of a prion peptide complex are determined by analysis of their L-band EPR spectra.

The resolution of MALDI MS imaging is limited by the displacement of analytes during matrix deposition or by laser focal diameter. Here we present three methods that minimize the displacement of analytes during matrix deposition, including a method where image resolution is not limited by the laser focal diameter. The first method, matrix solution fixation, simultaneously fixes tissue while depositing matrix and is optimal for analyzing proteins and for applications requiring a fast preparation time. This method is characterized by compatibility with histology methods and laser focal diameter-limited resolution. The second method, a sensor controlled aerosol, is characterized by aerosol droplet size-limited resolution and is optimal for small molecules, including lipids, peptides, and drug-like molecules. The third method, microinjection with matrix, selectively deposits matrix upon cells of interest, offers cellular resolution and is compatible with most analytes. A flow chart summarizing methods is provided so that users may design a tissue preparation strategy based upon their resources and experimental goals.

Metallo-beta-lactamases are zinc-dependent hydrolases that inactivate beta-lactam antibiotics, rendering bacteria resistant to them. Asp-120 is fully conserved in all metallo-beta-lactamases and is central to catalysis. Several roles have been proposed for Asp-120, but so far there is no agreed consensus. We generated four site-specifically substituted variants of the enzyme BcII from Bacillus cereus as follows: D120N, D120E, D120Q, and D120S. Replacement of Asp-120 by other residues with very different metal ligating capabilities severely impairs the lactamase activity without abolishing metal binding to the mutated site. A kinetic study of these mutants indicates that Asp-120 is not the proton donor, nor does it play an essential role in nucleophilic activation. Spectroscopic and crystallographic analysis of D120S BcII, the least active mutant bearing the weakest metal ligand in the series, reveals that this enzyme is able to accommodate a dinuclear center and that perturbations in the active site are limited to the Zn2 site. It is proposed that the role of Asp-120 is to act as a strong Zn2 ligand, locating this ion optimally for substrate binding, stabilization of the development of a partial negative charge in the beta-lactam nitrogen, and protonation of this atom by a zinc-bound water molecule.

Calcium (Ca2+) is a key mediator of myocardial function. Calcium regulates contraction, and disruption of myocellular Ca2+ handling plays a role in cardiac pathologies such as arrhythmias and heart failure. This investigation examines sex differences in sensitivity of the contractile proteins to Ca2+ and myofibrillar Ca2+ delivery in the ventricular myocardium. Sensitivity of contractile proteins to Ca2+ was measured in weight-matched male and female Sprague-Dawley rats using the skinned ventricular papillary muscle fiber and Ca(2+)-stimulated Mg(2+)-dependent adenosine triphosphatase (ATPase) activity methodologies. Calcium delivery was examined by measuring the contractile response to a range of extracellular Ca2+ concentrations in isolated ventricular myocytes, papillary muscle, and the isolated perfused whole heart. Findings from studies in the whole heart suggest that at a fixed preload, the male left ventricle generates more pressure than a female ventricle over a range of extracellular Ca2+ concentrations. In contrast, results from myocyte and papillary muscle studies suggest that females require less extracellular Ca2+ to elicit a similar contractile response. Results obtained from the 2 methods used to determine sex differences in Ca2+ sensitivity were equivocal. Further studies are required to elucidate sex differences in myocardial Ca2+ handling and the reasons for disparate results in different heart muscle preparations. The results of these studies will lead to the design of sex-optimized therapeutic interventions for cardiac disease.

Study Design: Biomechanical testing of the pullout strengths of pedicle screws placed by two different techniques in adult human cadaveric cervical spines., Objectives: To determine whether there is a significant difference in screw purchase of two commonly proposed methods of cervical pedicle screw insertion., Summary of Background Data: Wiring techniques remain the gold standard for posterior cervical fixation. However, absent or deficient posterior elements may dictate the use of alternative fixation techniques. Cervical pedicle screws have been shown to have significantly higher pullout strength than lateral mass screws., Methods: Fifty fresh disarticulated human vertebrae (C3-C7) were evaluated with computed tomography for anatomic disease and pedicle morphometry. The right and left pedicles were randomly assigned to either a standard method or the Abumi insertion method. In the latter technique the cortex and cancellous bone of lateral mass are removed with a high-speed burr, which provides a direct view of the pedicle introitus. The pedicle is then probed and tapped and a 3.5-mm cortical screw inserted. Each screw was subjected to a uniaxial load to failure., Results: There was no significant difference in the mean pullout resistance between the Abumi (696 N) and standard (636.5 N) insertion techniques (P = 0.41). There was no difference in pullout resistance between vertebral levels or within vertebral levels. Two (4%) minor pedicle wall violations were observed., Conclusion: In selected circumstances pedicle screw instrumentation of the cervical spine may be used to manage complex deformities and patterns of instability. Surgeons need not be concerned about reduced screw purchase when deciding between the Abumi method and its alternatives.

Study Design: Independently assessed radiographic and anatomic comparison of device implantation methods., Objectives: To compare the relative accuracy of two techniques of inserting cervical pedicle screws., Summary of Background Data: In an attempt to define the anatomic risks of cervical pedicle screw insertion, image-guided stereotactic technology was shown to be superior to some other methods in vitro.- Meanwhile, in vivo experience with Abumi's technique of screw insertion has had few clinically relevant instances of screw malposition. There has been no direct comparison between current image-guided technology and Abumi's fluoroscopically assisted technique., Methods: The pedicles (C3-C7) of human cadaveric cervical spines were instrumented with 3.5-mm screws with either of two techniques. Cortical integrity and potential neurovascular injury were independently assessed by computed tomographic (CT) scans and anatomic dissection. A cortical breach was considered "critical" if the screw encroached on any vital structure. If any part of the screw violated the cortex of the pedicle but no vital structure was at risk for injury, the breach was classified as "noncritical.", Results: In Group I (StealthStation; Sofamor-Danek, Memphis, TN), 82% of screws were placed in the pedicle, and 18% had a critical breach. In Group II (Abumi technique), 88% of screws were placed in the pedicle, and 12% had a critical breach. No statistically significant differences were demonstrated between each group (P = 0.59). Regarding pedicle dimensions and safety of insertion, a critical pedicle diameter of 4.5 mm was determined to be the size below which a critical breach was likely, but above which there was a significantly greater likelihood for safe screw placement. The most common structure injured in each group was the vertebral artery., Conclusions: The use of a computer-assisted image guidance system did not enhance safety or accuracy in placing pedicle screws compared with Abumi's technique. Both techniques have a noteworthy risk of injuring a critical structure if inserted into the pedicles with a diameter of less than 4.5 mm. Under laboratory conditions, pedicles with a diameter of more than 4.5 mm have a significantly greater likelihood of being safely instrumented by either technique. These data indicate that cervical pedicle screw placement is feasible, but it should be reserved for selected circumstances with clear indications and in the presence of suitable pedicle morphology.

This review will summarize the major efforts currently underway to develop osteoinductive bone graft substitutes for minimally invasive spine fusions. The primary categories of substitute include purified bone growth factors, recombinant bone growth factors, and growth factors delivered by gene therapy approaches. Clinical trials are underway for the purified and recombinant bone growth factors and pre-clinical studies have yielded promising results for a variety of gene therapy techniques for generating bone.

Background: Few reports address the high-risk patient population with concomitant critical carotid and left main coronary disease with left ventricular dysfunction. To decrease the risks involved with the simultaneous and traditional staged surgical approaches, we developed a rapid staging strategy using an intraaortic balloon pump., Methods: Between 1992 and 1996, 20 patients presented with a high-risk "triad" defined by greater than 70% stenosis of the left main coronary artery, ejection fraction less than 0.30, and greater than 90% stenosis of the internal carotid artery. An intraaortic balloon pump was placed immediately before carotid endarterectomy under angiographic guidance. Less than 24 hours later (mean, 18 hours) coronary artery bypass grafting was performed, and the intraaortic balloon pump was removed the day of coronary artery bypass grafting in all cases (total IABP duration, <36 hours)., Results: Eighteen patients (18/20) were extubated on the day of coronary artery bypass grafting (mean, 12 hours). Sixteen patients (16/20) were transferred from the intensive care unit within 48 hours, with total hospital stay ranging from 6 to 12 days (mean, 8 days). There were no 30-day postoperative deaths, myocardial infarctions, or neurologic, vascular, bleeding, or other major complications. At a mean 29.4-month follow-up, there were two noncardiac deaths and no neurologic events. Six-month, 1-year, and 2-year follow-up ultrasounds showed all operative carotid arteries remained patent., Conclusions: A rapid staged procedure with angiographically guided placement of the intraaortic balloon pump was safe and effective in this very high risk patient population. It may be an option to decrease the risks involved with simultaneous operations and increase the efficiency and safety of "traditional" staged carotid and coronary artery bypass grafting procedures.

A fraction of each secreted protein is retained and degraded by the endoplasmic reticulum (ER) quality control apparatus that restricts export to correctly folded proteins. The intrinsic biophysical attributes that determine efficiency of escape from this proofreading process have been examined by expressing mutants of bovine pancreatic trypsin inhibitor (BPTI) in yeast. Secretion efficiency is strongly correlated with thermodynamic stability for a series of six point mutations of BPTI. No correlation of secretion efficiency with either oxidative folding or refolding rates in vitro is found; both the rapidly folded Y35L BPTI mutant and the slowly unfolded G36D BPTI mutant exhibit low secretion efficiency. Elimination of cysteines 14 and 38 by mutagenesis does not increase secretion efficiency, indicating that intramolecular thiol/disulfide rearrangements are not primarily responsible for retention and degradation of destabilized BPTI variants. Mutant yeast strains with diminished ER-associated degradation do not secrete BPTI more efficiently, indicating that retention and degradation are separable processes. These data support a model for ER quality control, wherein protein folding is functionally reversible and the relative rates of folding, unfolding, vesicular export, and retention determine secretion efficiency.

A chaperone from Methanococcus jannaschii has been purified to homogeneity with a single chromatographic step. The chaperone was identified and characterized using activity assays for characteristic chaperone abilities. The M. jannaschii chaperone binds unfolded proteins, protects proteins against heat-induced aggregation, and has a strongly temperature dependent ATPase activity. The chaperone has also been shown to inhibit the spontaneous refolding of a mesophilic protein at low temperatures. The purified chaperone complex has a M(r) of about 1,000,000 and consists of a single type of subunit with an approximate M(r) of 60,000. Analysis of partial sequence data reveals that this chaperone is the predicted protein product of the previously identified chaperonin gene in M. jannaschii (BULT et al., 1996). To our knowledge, this is the first functional characterization of a chaperone from a methanogen.

Bovine pancreatic trypsin inhibitor (BPTI) has been widely used as a model protein to investigate protein structure and folding pathways. To study the role of its three disulfide bonds in folding, proofreading, and secretion of BPTI in an intact eucaryotic cell, BPTI was expressed and secreted from a synthetic gene in the yeast Saccharomyces cerevisiae. Site-directed mutagenesis was used to create all possible single and pairwise cysteine to alanine BPTI mutants, and the effect of these mutations on secretion efficiency was determined. The 5-55 disulfide bond is found to be essential for secretion-loss of either Cys5, Cys55, or both prevents secretion. Removal of the 14-38 disulfide bond results in a small reduction of secretion, but individual Cys14 or Cys38 replacements reduce secretion efficiency by 30%. Cys30 and Cys30-51 mutants are secreted at half the level of wild-type BPTI, while secretion of the Cys51 mutant is reduced by 90%. BPTI containing only a single disulfide bond (5-55) is not secreted. No relationship is observed between secretion efficiency and in vitro folding or unfolding rates, but mutant BPTI secretion is directly correlated with the in vitro unfolding temperature Tm and the free energy of stabilization provided by each of the three disulfides. These results indicate that structural fluctuations rather than the time-averaged structure observed by NMR or X-ray crystallography may determine recognition of a protein as misfolded and subsequent retention and degradation.

Study Design: This was a human cadaver study of the accuracy of biplanar roentgenography in determining pedicle screw position., Objective: To determine the independent accuracy of radiologic evaluation of screw placement and to determine if there are any particular screw malpositions that are more likely to produce a false sense of acceptable screw position., Summary of Background Data: Other investigators have reported the correlation between radiologic evaluation and anatomic dissection. However, in those studies the radiologic evaluation was not independent of the surgeons placing the screws. There has been no comment in the literature regarding particular screw malpositions that would lead the surgeon into a false sense of successful screw placement., Methods: Pedicle screws were placed in cadaver spines, and biplanar roentgenograms of the specimens were evaluated by independent observers. The results of the roantgenogram evaluation then were compared to those of the anatomic dissection., Results: The accuracy of roentgenogram evaluation varied from 73% to 83%, depending on the experience of the surgeon grading the roentgenograms. Screws misplaced medially into the spinal canal are more likely to give the surgeon a false sense of successful screw placement., Conclusions: The surgeon must not rely solely on the roentgenograms, but instead continue to use tactile sensory skills, anatomic knowledge, and additional modalities such as electromyography monitoring.

In this paper algorithms of neural-network type are introduced for solving estimation and classification problems when assumptions about independence, Gaussianity, and stationarity of the observation samples are no longer valid. Specifically, the asymptotic normality of several nonparametric classification tests is demonstrated and their implementation using a neural-network approach is presented. Initially, the neural nets train themselves via learning samples for nominal noise and alternative hypotheses distributions resulting in near optimum performance in a particular stochastic environment. In other than the nominal environments, however, high efficiency is maintained by adapting the optimum nonlinearities to changing conditions during operation via parallel networks, without disturbing the classification process. Furthermore, the superiority in performance of the proposed networks over more traditional neural nets is demonstrated in an application involving pattern recognition.

Two-dimensional 'joint' interval distributions of sequential interspike (ISIs) are a commonly used tool in neuronal spike train analysis. We present and evaluate here a modification of the joint interval plot using ranked ISIs. This modification provides clearer graphical evaluation of serial dependence in ISI sequences, a distribution-free basis for isolating changes in serial dependence across experimental treatments from changes in ISI distributions, and a basis for unambiguous statistical tests of serial dependence and stationarity. To validate this method and illustrate the advantages of its use we have applied it to both single-neuron spike trains recorded from cultured mammalian spinal cord neurons and artificial spike trains generated by stochastic models with defined burst envelopes and serial dependencies.

The results of diskectomy without fusion at L4-5 were compared with those at L5-S1. Strict indications for surgery had been applied to each group. Evaluation was carried out using the Oswestry Disability scale, as well as a modified Smiley-Webster scale, and a subjective improvement rating scale, as well as documenting work status, whether any future surgery was required, and other factors. Results were placed into categories based on these evaluation methods and were analyzed statistically. Average follow-up was 51 months with a minimum of 24 months. Overall excellent and good results occurred in 81% of patients in both groups. No difference in reoperation rate was detected between the two groups. Women were more likely to undergo a subsequent procedure, usually fusion. Equally satisfactory results can be obtained at L4-5 and L5-S1 if strict selection criteria are used.

A fifty-two-year-old woman with angina pectoris due to coronary-subclavian steal syndrome through a left internal mammary artery graft placed distal to a left anterior descending artery stenosis is presented. Retrograde flow through the mammary artery graft due to severe left subclavian stenosis was observed angiographically. Accordingly, left subclavian balloon angioplasty was performed, restoring normal antegrade flow through the internal mammary artery graft and resulting in resolution of the patient's symptoms. The patient was subsequently discharged with no evidence of angina. Carotid-subclavian bypass surgery was avoided, reducing patient discomfort, procedural risk, and expense.

This report describes the reluctance of individuals exposed to a man-made disaster to utilize formal mental health services. Measures were obtained in an initial screening 6 months after a shooting for 24 exposed school personnel. Data from the initial screening were compared for those who did not participate in a follow-up screening 12 months later (N = 11) and those who did (N = 13). Follow-up nonparticipants reported: more posttraumatic stress disorder symptoms, especially avoidance; recall of life threat during the event; feeling depressed; and an increase in positivity toward victims but not about their work or mental health professionals. The authors conclude that some individuals may avoid formal mental health services because they serve as cues for malignant memory retrieval and discuss implications for service delivery.

Sixty-four children and 66 adults were screened for post-traumatic stress disorder 6 to 14 months after a school shooting. Although there were no differences in overall frequencies of DSM-III-R diagnoses or cluster endorsements, there were developmental influences. Post-traumatic stress disorder was associated more with emotional states recalled from the disaster than with proximity. Emotional states mediated the formation of malignant memories leading to symptomatology, suggesting that postdisaster intervention be offered on the basis of degree of emotional reaction as well as proximity.

The temporal consistency of the WAIS-R Memory/Freedom from Distractibility factor and its intrafactorial components were measured over a 4-wk. period in a nonclinical sample of 22 undergraduates. A modest but significant consistency coefficient of .49 was obtained for Memory/Freedom from Distractibility. Neither intrafactorial component manifested significant temporal consistency over four weeks. Significant retest improvements were expected and observed on Memory/Freedom from Distractibility and Advanced Computation. These retest improvements were interpreted in terms of task familiarity rather than specific content recall. The reported temporal consistency coefficients appear to represent the lowest consistency for these neuropsychological constructs. The routine use of Memory/Freedom from Distractibility was questioned pending more comprehensive measurement of reliability.

Objective: The purpose of the study was to investigate the effect of symptom threshold and criteria set selections on the diagnosis of posttraumatic stress disorder (PTSD) in adults and children exposed to a man-made disaster and determine how well DSM-III and its successors agree., Method: Data gathered in the course of a voluntary clinical screening for PTSD in 66 adults and 64 children 6 to 14 months after exposure to a school shooting were analyzed according to DSM-III, DSM-III-R, and proposed DSM-IV criteria for PTSD diagnosis and cluster endorsement using liberal (occurring at least a little of the time), moderate (occurring at least some of the time), and conservative (occurring at least much or most of the time) symptom thresholds., Results: Within DSM-III, DSM-III-R, and proposed DSM-IV, selection of liberal, moderate, and conservative symptom thresholds had robust effects on rates of diagnoses; liberal thresholds allowed the greatest frequencies of diagnosis. Compared with DSM-III and proposed DSM-IV, DSM-III-R generally diagnosed the fewest cases. Agreements between DSM-III-R and proposed DSM-IV were good, while agreements between DSM-III and its successors varied for children and adults., Conclusions: Diagnostic rates and agreements were complexly influenced by interactions among threshold and revisions in symptom clusters. The present study suggests that attempts to refine PTSD classification consider specification of symptom threshold intensity and supports the view that modification of criteria sets be undertaken with caution.

The reliability coefficients of the normative WISC-R factors (Verbal Comprehension, Perceptual Organization, Freedom from Distractibility) were computed for each age level of the standardization sample from a formula provided by Tellengen and Briggs (1967). Results indicated that the Verbal Comprehension and Perceptual Organization factors possess generally equivalent reliability to their analogous intelligence quotients. Freedom from Distractibility possesses adequate reliability for routine clinical interpretation. Criticisms of the reliability of the third factor (Distractibility) as being too low for individual assessment appear unwarranted. A table of reliability coefficients is presented for each age level in the standardization sample.