Imaging of the temporomandibular joint.

Temporomandibular disorders are common, especially in young to middle-aged women, and most settle with supportive treatment. Imaging is indicated for the small percentage of cases that do not respond to conservative management and when the diagnosis is no doubt. The temporomandibular joint (TMJ) is a bilateral synovial articulation between the mandible and skull base. It has an intra-articular disc dividing the joint into superior and inferior compartments and the articular surfaces are lined with fibrocartilage. The normal imaging anatomy of the TMJ is described and illustrated. Different movements occur in each joint compartments: a hinge movement in the inferior joint space and translation or gliding in the superior joint space. Internal derangement is the commonest disorder affecting the TMJ and is most commonly due to disc displacement, followed by osteoarthritis and inflammatory arthritides. The imaging findings, primarily on magnetic resonance imaging (MRI) and computed tomography (CT), of internal derangement and less common disorders of the joint, are reviewed and illustrated. Optimal imaging protocols are discussed with detailed reporting guidelines.

Systematic review of current randomised control trials in chronic subdural haematoma and proposal for an international collaborative approach.

BACKGROUND: Chronic subdural haematoma (CSDH) is a pathology that is frequently encountered by neurosurgeons. Nevertheless, there is a lack of guidelines based on solid evidence. There has been a recent and considerable increase in the interest on management and outcomes for CSDH. Therefore, we systematically reviewed all currently running randomised controlled trials (RCTs) in chronic subdural haematoma to understand the areas under investigation and plan future collaborative trials. METHODS: Clinical trials databases (Cochrane Controlled Register of Trials, WHO ICTRP and clinical trials.gov) were searched for trials relevant to chronic subdural haematoma. It was then established which trials were currently running and fulfilled robust research methodology for a RCT. RESULTS: There are 26 currently running RCTs in CSDH, with the most common topics covering application of steroids (7), surgical techniques (5) and tranexamic acid (5). Further to this, there are trials running on other pharmacological agents (4), middle meningeal artery (MMA) embolisation (2) and peri-operative management (3). CONCLUSIONS: Pharmacological agents are a particular focus of CSDH management currently, and a wealth of studies on steroids will hopefully lead to more harmonised, evidence-based practice regarding this in the near future. Surgical techniques and new procedures such as MMA embolisation are also important focuses for improving patient outcomes. There is an on-going need for future RCTs and evidence-based guidelines in CSDH, particularly including low- and middle-income countries, and it is hoped that the establishment of the iCORIC (International COllaborative Research Initiative on Chronic Subdural Haematoma) will help address this.

Determinants of assault-related violence in the community: potential for public health interventions in hospitals.

BACKGROUND: Data from emergency departments (EDs) in England describe the epidemiology of violent assaults. However, the potential of such data to inform hospital-based public health interventions remains unknown. OBJECTIVE: To identify determinants of assaults using ED data to inform development of programmes delivered in acute Trusts for reducing assault-related injuries in the community. METHODS: Data were collected from a large North London acute Trust on assault-related injuries reporting to A&E over 18 months (July 2010-February 2012). Information was recorded on patient demographics and assaults (place of assault, type of assault, relation to assailant) through questionnaires administered by ED reception staff. RESULTS: 1210 assaults were recorded between July 2010 and February 2012. 18% of assaults were severe (strangling, stabbings, sexual assaults). 75% of assault victims were men, 37% were young adults (20-30 years) and 15% were teenagers. A higher proportion of victims lived in more deprived areas. Apart from public streets (48%), the main location of assaults was at home (20%). Female compared with male victims were significantly more likely to be both assaulted at home (OR 6.13; 95% CI 4.41 to 8.54) and to be assaulted by a known assailant (family member, friend, partner/ex-partner; OR 8.20, 95% CI 5.85 to 11.48). CONCLUSIONS: The results highlight the notable contribution of domestic violence to assaults presenting to hospital ED. Such findings can be used to plan interventions such as screening hospital patients for domestic violence. ED data have the potential to inform hospital-based initiatives to address issues such as assaults in the local population.

Attitudes and barriers to employment in HIV-positive patients.

BACKGROUND: Unemployment in the human immunodeficiency virus (HIV) population remains a major issue. Recent changes in the benefits system have triggered concerns about (re)integration into work for adults with HIV. AIMS: To examine attitudes and barriers to employment in HIV patients. METHODS: We undertook a cross-sectional study in the Royal Free HIV outpatient department from December 2008 to February 2009. The questionnaire collected data on demographics, date of HIV diagnosis, combination antiretroviral therapy, CD4 count, employment status, attitudes to work, psychological health and perception of barriers to employment. Logistic regression analyses were used to assess factors associated with not working. RESULTS: Five hundred and forty-five HIV patients took part. Overall, 26% were not working and of these, half (53%) had been unemployed for >5 years. Associations with not working were having been diagnosed with HIV >10 years before, poor psychological health and poor attitudes to employment. There was no association between objective measures of health (CD4 count) and employment status. Those not working were less likely to agree with that 'work is good for physical and mental health' (90 versus 97%: P < 0.01) and more likely to agree that 'should only work if 100% fit and well' (76 versus 51%: P < 0.001) compared to workers. Those currently not working had negative perceptions of their abilities to gain employment and to remain in work. CONCLUSIONS: There are opportunities for HIV services to provide psychological support around attitudes associated with unemployment and to help HIV-positive men in particular obtain and remain in work.

A Role for PGC-1α in Transcription and Excitability of Neocortical and Hippocampal Excitatory Neurons.

The transcriptional coactivator peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) is a critical regulator of genes involved in neuronal metabolism, neurotransmission, and morphology. Reduced PGC-1α expression has been implicated in several neurological and psychiatric disorders. An understanding of PGC-1α's roles in different cell types will help determine the functional consequences of PGC-1α dysfunction and/or deficiency in disease. Reports from our laboratory and others suggest a critical role for PGC-1α in inhibitory neurons with high metabolic demand such as fast-spiking interneurons. Here, we document a previously unrecognized role for PGC-1α in maintenance of gene expression programs for synchronous neurotransmitter release, structure, and metabolism in neocortical and hippocampal excitatory neurons. Deletion of PGC-1α from these neurons caused ambulatory hyperactivity in response to a novel environment and enhanced glutamatergic transmission in neocortex and hippocampus, along with reductions in mRNA levels from several PGC-1α neuron-specific target genes. Given the potential role for a reduction in PGC-1α expression or activity in Huntington Disease (HD), we compared reductions in transcripts found in the neocortex and hippocampus of these mice to that of an HD knock-in model; few of these transcripts were reduced in this HD model. These data provide novel insight into the function of PGC-1α in glutamatergic neurons and suggest that it is required for the regulation of structural, neurosecretory, and metabolic genes in both glutamatergic neuron and fast-spiking interneuron populations in a region-specific manner. These findings should be considered when inferring the functional relevance of changes in PGC-1α gene expression in the context of disease.

D+ platelet transfusions in D- patients: cause for concern?

Patients whose RBCs are D- may produce anti-D if they are exposed to D on donor RBCs. Except in emergency situations, patients whose RBCs lack D are transfused with only D- RBCs. Platelets carry no Rh antigens, but platelet units may be contaminated by RBCs that could carry D when these units are collected from D+ donors. The purpose of this study was to determine whether our policy of allowing D+ platelets to be transfused to patients whose RBCs type as D-, without the use of prophylactic Rh immunoglobulin (RhIG), results in D alloimmunization. The transfusion records of all patients who received platelet transfusions from December 2004 to March 2007 were reviewed. Transfusion recipients were evaluated with pretransfusion ABO and D typings, and an antibody screen. Recipients were reevaluated in the same manner before subsequent transfusions. Transfusion records of 114 D- patients were analyzed. Overall, 104 patients received D+ platelets; 67 had repeat antibody screening after transfusion. No patients were shown to make anti-D after platelet transfusion. There was no evidence of D alloimmunization as a result of transfusion of D+ platelets in any D- patient during this study. The data do not support the practice of restricting D- patients to receiving only D- apheresis platelets, even among patients with chronic transfusion requirements. Prophylactic use of RhIG for D+ apheresis platelet transfusions in D- patients also appears to be unnecessary.

Crown and bridge disassembly--when, why and how.

Crown and bridgework has a finite life span and fails for a number of reasons. Removal is often by destructive means. There are a number of clinical circumstances, however, in which a conservative disassembly would aid the practitioner in completing restorative/endodontic procedures. The aims of this paper are to provide a classification for crown and bridge removal systems; describe how a number of such systems work; and when and why they might be considered.

Crown and bridge disassembly--when, why and how.

UNLABELLED: Crown and bridgework has a finite life span and fails for a number of reasons. Removal is often by destructive means. There are a number of clinical circumstances, however, in which a conservative disassembly would aid the practitioner in completing restorative/endodontic procedures. The aims of this paper are to provide a classification for crown and bridge removal systems; describe how a number of such systems work; and when and why they might be considered. CLINICAL RELEVANCE: Crown and bridge removal is a frequent occurrence for dentists. There are many situations in which salvaging extracoronal restorations may be more helpful than their destruction.

The impact of intraoperative microbreaks with exercises on surgeons: A multi-center cohort study.

Recent literature has demonstrated ergonomic risk to surgeons in the operating room. One method used in other industries to mitigate these ergonomic risks is the incorporation of microbreaks. Thus, intraoperative microbreaks with exercises in a non-crossover design were studied. Fifty-six attending surgeons from 4 Medical Centers volunteered first in a day of their regular surgeries and then second day where there were microbreaks with exercises that could be performed in the sterile field, answering questions after each case, without significantly increasing the duration of their surgeries. Surgeons self-reported improvement or no change in their mental focus (88%) and physical performance (100%) for the surgical day incorporating microbreaks with exercises. Discomfort in the shoulders was significantly reduced while distractions and flow impact was minimal. Eighty-seven percent of the surgeons wanted to incorporate the microbreaks with exercises into their OR routine. Intraoperative microbreaks with exercises may be a way to mitigate work-related musculoskeletal fatigue, pain and injury.

Low-Dose CT for Craniosynostosis: Preserving Diagnostic Benefit with Substantial Radiation Dose Reduction.

BACKGROUND AND PURPOSE: Given the positive impact of early intervention for craniosynostosis, CT is often performed for evaluation but radiation dosage remains a concern. We evaluated the potential for substantial radiation dose reduction in pediatric patients with suspected craniosynostosis. MATERIALS AND METHODS: CT projection data from pediatric patients undergoing head CT for suspected craniosynostosis were archived. Simulated lower-dose CT images corresponding to 25%, 10%, and 2% of the applied dose were created using a validated method. Three neuroradiologists independently interpreted images in a blinded, randomized fashion. All sutures were evaluated by using 3D volume-rendered images alone, and subsequently with 2D and 3D images together. Reference standards were defined by reader agreement by using routine dose and 2D and 3D images. Performance figures of merit were calculated based on reader response and confidence. RESULTS: Of 33 pediatric patients, 21 had craniosynostosis (39 positive sutures and 225 negative sutures). The mean volume CT dose index was 15.5 ± 2.3 mGy (range, 9.69-19.38 mGy) for the routine dose examination. Average figures of merit for multireader analysis ranged from 0.92 (95% CI, 0.90-0.95) at routine pediatric dose to 0.86 (95% CI, 0.79-0.94) at 2% dose using 3D images alone. Similarly, pooled reader figures of merit ranged from 0.91 (95% CI, 0.89-0.95) at routine pediatric dose to 0.85 (95% CI, 0.76-0.95) at 2% dose using 2D and 3D images together. At 25% and 10% dose, 95% CI of the difference in figures of merit from routine dose included 0, suggesting similar or noninferior performance. CONCLUSIONS: For pediatric head CT for evaluation of craniosynostosis, dose reductions of 75%-90% were possible without compromising observer performance.

Sylvian fissure asymmetries in monozygotic twins: a test of laterality in schizophrenia.

To address prior reports that schizophrenia is associated with loss of normal brain asymmetry and that it might be linked to a defect of a gene controlling cerebral lateralization, we measured on three-dimensional cortical renderings from magnetic resonance imaging (MRI) scans the lengths and angles of the sylvian fissures in 10 normal monozygotic (MZ) twin pairs (n = 10 pairs) and in 10 MZ pairs discordant for schizophrenia (n = 10 pairs). We confirmed in both sets of twins the expected normal asymmetries of length and angle of the sylvian fissure. We also confirmed that the length asymmetry occurs solely in the region of the planum temporale. In the discordant twins, affected and unaffected twins did not differ in asymmetry measures, thus failing to support an association between illness per se and diminished asymmetry. Moreover, the discordant twins as a group did not differ from the normal twins as a group, thus failing to confirm the hypothesis of a genetic association with abnormal asymmetry. The implications of variations in methodology and patient samples are discussed.

Cortical gyral anatomy and gross brain dimensions in monozygotic twins discordant for schizophrenia.

BACKGROUND: This study combines recent advances in three-dimensional neuroimaging technology and the genetic constraints inherent in monozygotic (MZ) twins to examine surface gyral anatomy and gross brain dimensions in monozygotic twin pairs discordant for schizophrenia. Results are presented and evaluated with respect to prior observations of cortical anomalies in schizophrenia and the hypothesis that schizophrenia involves cortical maldevelopment. DESIGN: Three-dimensional renderings from volumetric magnetic resonance imaging (MRI) data of 13 MZ twin pairs discordant for schizophrenia and nine normal MZ pairs were studied. Qualitative assessments of left and right hemisphere surfaces were made by raters blind to diagnosis in an effect to identify developmental gyral abnormalities such as vertical temporal gyri or microgyria. Measurement of brain hemisphere length, area, and volume were also determined. These data were compared within discordant MZ schizophrenia pairs, within normal MZ pairs, and between matched unaffected discordant and normal MZ groups. RESULTS: Raters did not identify qualitatively abnormal gyri in the schizophrenia subjects to enable distinction from their unaffected co-twins or from normal controls. Brain hemisphere volumes in the affected DS were significantly smaller bilaterally by about 3% compared with their unaffected DS co-twins, who did not differ from normals on this measure. CONCLUSIONS: We were unable to confirm previous reports of vertical gyri or localized gyral thinning as being characteristic of the cortical anatomy of schizophrenia. If cortical maldevelopment is associated with schizophrenia it does not appear to disrupt gross gyral pattern formation in these ways. The quantitative results of diminished hemisphere volume and length in the twins with schizophrenia are consistent with previous reports of smaller brain size in schizophrenia. Our results suggest that this is a bilateral phenomenon that may be dependent, at least in part, on environmental factors.

Mice lacking the transcriptional coactivator PGC-1α exhibit alterations in inhibitory synaptic transmission in the motor cortex.

Peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) is a transcriptional coactivator known to regulate gene programs in a cell-specific manner in energy-demanding tissues, and its dysfunction has been implicated in numerous neurological and psychiatric disorders. Previous work from the Cowell laboratory indicates that PGC-1α is concentrated in inhibitory interneurons and is required for the expression of the calcium buffer parvalbumin (PV) in the cortex; however, the impact of PGC-1α deficiency on inhibitory neurotransmission in the motor cortex is not known. Here, we show that mice lacking PGC-1α exhibit increased amplitudes and decreased frequency of spontaneous inhibitory postsynaptic currents in layer V pyramidal neurons. Upon repetitive train stimulation at the gamma frequency, decreased GABA release is observed. Furthermore, PV-positive interneurons in PGC-1α -/- mice display reductions in intrinsic excitability and excitatory input without changes in gross interneuron morphology. Taken together, these data show that PGC-1α is required for normal inhibitory neurotransmission and cortical PV-positive interneuron function. Given the pronounced motor dysfunction in PGC-1α -/- mice and the essential role of PV-positive interneurons in maintenance of cortical excitatory:inhibitory balance, it is possible that deficiencies in PGC-1α expression could contribute to cortical hyperexcitability and motor abnormalities in multiple neurological disorders.

Calcium-permeable presynaptic kainate receptors involved in excitatory short-term facilitation onto somatostatin interneurons during natural stimulus patterns.

Schaffer collateral synapses in hippocampus show target-cell specific short-term plasticity. Using GFP-expressing Inhibitory Neuron (GIN) transgenic mice that express enhanced green fluorescent protein (EGFP) in a subset of somatostatin-containing interneurons (SOM interneurons), we previously showed that Schaffer collateral synapses onto SOM interneurons in stratum (S.) radiatum have unusually large (up to 6-fold) paired-pulse facilitation. This results from a low initial release probability and the enhancement of facilitation by synaptic activation of presynaptic kainate receptors. Here we further investigate the properties of these kainate receptors and examine their effects on short-term facilitation during physiologically derived stimulation patterns, using excitatory postsynaptic currents recorded in S. radiatum interneurons during Schaffer collateral stimulation in acute slices from juvenile GIN mice. We find that GluR5 and GluR6 antagonists decrease short-term facilitation at Schaffer collateral synapses onto SOM interneurons with no additive effects, suggesting that the presynaptic kainate receptors are heteromers containing both GluR5 and GluR6 subunits. The calcium-permeable receptor antagonist 1-napthyl acetyl spermine (NASPM) both mimics and occludes the effect of the kainate receptor antagonists, indicating that the presynaptic kainate receptors are calcium permeable. Furthermore, Schaffer collateral synapses onto SOM interneurons show up to 11-fold short-term facilitation during physiologically derived stimulus patterns, in contrast to other interneurons that have less than 1.5-fold facilitation. Blocking the kainate receptors reduces facilitation in SOM interneurons by approximately 50% during the physiologically derived patterns and reduces the dynamic range. Activation of calcium-permeable kainate receptors containing GluR5/GluR6 causes a dramatic increase in short-term facilitation during physiologically derived stimulus patterns, a mechanism likely to be important in regulating the strength of Schaffer collateral synapses onto SOM interneurons in vivo.