A stake in the game: Can radiographer image interpretation improve X-ray quality? A scoping review

BACKGROUND

Image quality is an important factor in imaging optimisation and diagnosis. Many determinants of image quality are controlled by the radiographer; therefore, radiographer-led strategies may be key to improving X-ray image quality. This review examines the literature on radiographer-led diagnostic evaluation to establish its potential to improve X-ray image quality.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-analyses Extension for Scoping Reviews and the Joanna Briggs Institute Manual for Evidence Synthesis Scoping Review were used to review studies relevant to the impact of radiographer-led diagnostic evaluation on image quality. CINHAL, Embase, Scopus, Web of Science and Medline databases were searched for relevant articles. Search terms synonymous with radiographer, commenting, and image quality were used and studies that examined any type of radiographer-led image interpretation and its relationship to image quality in X-ray based modalities were reviewed.

RESULTS

Fourteen studies that met the inclusion criteria were reviewed. All the studies reviewed unanimously reported a positive association between radiographer image interpretation and image quality in X-ray based modalities. Five emerging themes were identified to be responsible for the improvement in image quality: increased understanding of image quality requirements, improved technical skills, enhanced ability to utilise supplementary imaging and repeats, collaborative upskilling of colleagues, and a complementary interaction between diagnostic and radiographic skills that serves to enhance image quality.

CONCLUSIONS

The findings demonstrate that radiographer image interpretation is a useful strategy to optimise the quality of X-ray examinations.

IMPLICATIONS FOR PRACTICE

The findings highlight a new avenue to improve X-ray quality in the clinical environment and support evidence-based uptake of preliminary image evaluation systems. These findings also support the integration of radiographer commenting alongside technical image quality in teaching curricula.

Measurement of the Positive Muon Anomalous Magnetic Moment to 0.20 ppm

We present a new measurement of the positive muon magnetic anomaly, a_{μ}≡(g_{μ}-2)/2, from the Fermilab Muon g-2 Experiment using data collected in 2019 and 2020. We have analyzed more than 4 times the number of positrons from muon decay than in our previous result from 2018 data. The systematic error is reduced by more than a factor of 2 due to better running conditions, a more stable beam, and improved knowledge of the magnetic field weighted by the muon distribution, ω[over ˜]_{p}^{'}, and of the anomalous precession frequency corrected for beam dynamics effects, ω_{a}. From the ratio ω_{a}/ω[over ˜]_{p}^{'}, together with precisely determined external parameters, we determine a_{μ}=116 592 057(25)×10^{-11} (0.21 ppm). Combining this result with our previous result from the 2018 data, we obtain a_{μ}(FNAL)=116 592 055(24)×10^{-11} (0.20 ppm). The new experimental world average is a_{μ}(exp)=116 592 059(22)×10^{-11} (0.19 ppm), which represents a factor of 2 improvement in precision.

Can simulation-based education or other education interventions replace clinical placement in medical radiation sciences? A narrative review

OBJECTIVES

In response to increasing student enrolment and workload pressures from the Covid-19 pandemic, a recent focus on health student preparation programs has been on curricula adaptations and replacement of clinical placement time with alternative education activities. The aim of the narrative review was to explore the current evidence relating to education activities in Medical Radiation Sciences (MRS) used to replace clinical placements or part of clinical placements. Medline, CINAHL and Web of Science databases were used to search for articles published between 2017 and 2022. Data from the literature was summarised into (1) planning and development of clinical replacement learning activities in MRS, (2) evaluation of clinical replacement activities, and (3) benefits and challenges of clinical replacement in MRS.

KEY FINDINGS

Planning and development of clinical replacement learning activities in MRSrequires support from a wide range of stakeholders, and evidence from activities already implemented exists. Activities largely encompass an institution-specific focus. Developed clinical replacement activities use a blended approach, with simulation-based education (SBE) as a main teaching platform. Evaluation of clinical replacement activities are largely focused on students' achievement of learning objectives relating to practical and communication skills. Emerging evidence based on small student samples shows that clinical and clinical replacement activities provide similar results in terms of learning objectives.

CONCLUSION

Benefits and challenges of clinical replacement in MRS are similar to those presented in the other health professions. The balance between quality and quantity of teaching and learning experiences for clinical skill development in MRS needs to be further investigated.

IMPLICATIONS FOR PRACTICE

To meet the dynamic challenges of the health care environment and MRS profession, a major goal in the future will be to affirm the benefit of clinical replacement activities for MRS students.

Measurement of the Positive Muon Anomalous Magnetic Moment to 0.46 ppm

We present the first results of the Fermilab National Accelerator Laboratory (FNAL) Muon g-2 Experiment for the positive muon magnetic anomaly a_{μ}≡(g_{μ}-2)/2. The anomaly is determined from the precision measurements of two angular frequencies. Intensity variation of high-energy positrons from muon decays directly encodes the difference frequency ω_{a} between the spin-precession and cyclotron frequencies for polarized muons in a magnetic storage ring. The storage ring magnetic field is measured using nuclear magnetic resonance probes calibrated in terms of the equivalent proton spin precession frequency ω[over ˜]_{p}^{'} in a spherical water sample at 34.7 °C. The ratio ω_{a}/ω[over ˜]_{p}^{'}, together with known fundamental constants, determines a_{μ}(FNAL)=116 592 040(54)×10^{-11} (0.46 ppm). The result is 3.3 standard deviations greater than the standard model prediction and is in excellent agreement with the previous Brookhaven National Laboratory (BNL) E821 measurement. After combination with previous measurements of both μ^{+} and μ^{-}, the new experimental average of a_{μ}(Exp)=116 592 061(41)×10^{-11} (0.35 ppm) increases the tension between experiment and theory to 4.2 standard deviations.

Nerve excitability changes related to muscle weakness in chronic progressive external ophthalmoplegia

OBJECTIVE

To explore potential spreading to peripheral nerves of the mitochondrial dysfunction in chronic progressive external ophthalmoplegia (CPEO) by assessing axonal excitability.

METHODS

CPEO patients (n=13) with large size deletion of mitochondrial DNA and matching healthy controls (n=22) were included in a case-control study. Muscle strength was quantified using MRC sum-score and used to define two groups of patients: CPEO-weak and CPEO-normal (normal strength). Nerve excitability properties of median motor axons were assessed with the TROND protocol and changes interpreted with the aid of a model.

RESULTS

Alterations of nerve excitability strongly correlated with scores of muscle strength. CPEO-weak displayed abnormal nerve excitability compared to CPEO-normal and healthy controls, with increased superexcitability and responses to hyperpolarizing current. Modeling indicated that the CPEO-weak recordings were best explained by an increase in the 'Barrett-Barrett' conductance across the myelin sheath.

CONCLUSION

CPEO patients with skeletal weakness presented sub-clinical nerve excitability changes, which were not consistent with axonal membrane depolarization, but suggested Schwann cell involvement.

SIGNIFICANCE

This study provides new insights into the spreading of large size deletion of mitochondrial DNA to Schwann cells in CPEO patients.

Simulation of dissolution in porous media in three dimensions with lattice Boltzmann, finite-volume, and surface-rescaling methods

We present a pore-scale dissolution model for the simulation of reactive transport in complex porous media such as those encountered in carbon-storage injection processes. We couple a lattice Boltzmann model for flow calculation with a finite-volume method for solving chemical transport equations, and allow the computational grid to change as mineral surfaces are dissolved according to first-order reaction kinetics. We appraise this scheme for use with high Péclet number flows in three-dimensional geometries and show how the popular first-order convection scheme is affected by severe numerical diffusion when grid Péclet numbers exceed unity, and confirm that this can be overcome relatively easily by using a second-order method in conjunction with a flux-limiter function. We then propose a surface rescaling method which uses parabolic elements to counteract errors in surface area exposed by the Cartesian grid and avoid the use of more complex embedded surface methods when surface reaction kinetics are incorporated. Finally, we compute dissolution in an image of a real porous limestone rock sample injected with HCl for different Péclet numbers and obtain dissolution patterns in concordance with theory and experimental observation. A low injection flow rate was shown to lead to erosion of the pore space concentrated at the face of the rock, whereas a high flow rate leads to wormhole formation.

Increased levels of cerebrospinal fluid JNK3 associated with amyloid pathology: links to cognitive decline

BACKGROUND

Alzheimer disease is characterized by cognitive decline, senile plaques of β-amyloid (Aβ) peptides, neurofibrillary tangles composed of hyperphosphorylated τ proteins and neuronal loss. Aβ and τ are useful markers in the cerebrospinal fluid (CSF). C-Jun N-terminal kinases (JNKs) are serine-threonine protein kinases activated by phosphorylation and involved in neuronal death.

METHODS

In this study, Western blots, enzyme-linked immunosorbent assay and histological approaches were used to assess the concentrations of Aβ, τ and JNK isoforms in postmortem brain tissue samples (10 Alzheimer disease and 10 control) and in CSF samples from 30 living patients with Alzheimer disease and 27 controls with neurologic disease excluding Alzheimer disease. Patients with Alzheimer disease were followed for 1-3 years and assessed using Mini-Mental State Examination scores.

RESULTS

The biochemical and morphological results showed a significant increase of JNK3 and phosphorylated JNK levels in patients with Alzheimer disease, and JNK3 levels correlated with Aβ42 levels. Confocal microscopy revealed that JNK3 was associated with Aβ in senile plaques. The JNK3 levels in the CSF were significantly elevated in patients with Alzheimer disease and correlated statistically with the rate of cognitive decline in a mixed linear model.

LIMITATIONS

The study involved different samples grouped into 3 small cohorts. Evaluation of JNK3 in CSF was possible only with immunoblot analysis.

CONCLUSION

We found that JNK3 levels are increased in brain tissue and CSF from patients with Alzheimer disease. The finding that increased JNK3 levels in CSF could reflect the rate of cognitive decline is new and merits further investigation.

Effect of active Aβ immunotherapy on neurons in human Alzheimer's disease

Amyloid β peptide (Aβ) immunization of Alzheimer's disease (AD) patients has been reported to induce amyloid plaque removal, but with little impact on cognitive decline. We have explored the consequences of Aβ immunotherapy on neurons in post mortem brain tissue. Eleven immunized (AN1792, Elan Pharmaceuticals) AD patients were compared to 28 non-immunized AD cases. Immunohistochemistry on sections of neocortex was performed for neuron-specific nuclear antigen (NeuN), neurofilament protein (NFP) and phosphorylated-(p)PKR (pro-apoptotic kinase detected in degenerating neurons). Quantification was performed for pPKR and status spongiosis (neuropil degeneration), NeuN-positive neurons/field, curvature of the neuronal processes and interneuronal distance. Data were corrected for age, gender, duration of dementia and APOE genotype and also assessed in relation to Aβ42 and tau pathology and key features of AD. In non-immunized patients, the degree of neuritic curvature correlated with spongiosis and pPKR, and overall the neurodegenerative markers correlated better with tau pathology than Aβ42 load. Following immunization, spongiosis increased, interneuronal distance increased, while the number of NeuN-positive neurons decreased, consistent with enhanced neuronal loss. However, neuritic curvature was reduced and pPKR was associated with Aβ removal in immunized patients. In AD, associations of spongiosis status, curvature ratio and pPKR load with microglial markers Iba1, CD68 and CD32 suggest a role for microglia in neurodegeneration. After immunization, correlations were detected between the number of NeuN-positive neurons and pPKR with Iba1, CD68 and CD64, suggesting that microglia are involved in the neuronal loss. Our findings suggest that in established AD this form of active Aβ immunization may predominantly accelerate loss of damaged degenerating neurons. This interpretation is consistent with in vivo imaging indicating an increased rate of cerebral atrophy in immunized AD patients.

CD8 encephalitis in HIV-infected patients receiving cART: a treatable entity

BACKGROUND

Despite its overall efficacy, combined antiretroviral therapy (cART) has failed to control human immunodeficiency virus (HIV) infection of the central nervous system (CNS). New acute and chronic neurological complications continue to be reported.

METHODS

We conducted a retrospective study of 14 HIV-infected patients with documented encephalitis, which was initially attributed to an undetermined origin. Brain magnetic resonance imaging (MRI) uniformly revealed unusual, multiple linear gadolinium-enhanced perivascular lesions.

RESULTS

All patients had manifested acute or subacute neurological symptoms; the brain MRIs indicating diffuse brain damage. The mean duration of HIV infection was approximately 10 years, and 8 patients were immunovirologically stable. Cerebrospinal fluid abnormalities with mildly elevated protein and pleocytosis with >90% lymphocytes, predominantly CD8, were found in all but 1 patient. The mean cerebral spinal fluid HIV load was 5949 copies/mL. Six patients reported a minor infection a few days prior to neurological symptoms, 2 patients presented criteria for the immune reconstitution inflammatory syndrome of the CNS, 2 were in virological escape, and 1 developed encephalitis after interruption of cART. Brain biopsies revealed inflammatory encephalitis associated with astrocytic and microglial activation as well as massive perivascular infiltration by polyclonal CD8(+) lymphocytes. All patients had been treated with glucocorticosteroids. The long-term therapeutic response varied from excellent, with no sequalae (n = 5), to moderate, with cognitive disorders (n = 4). The mean survival time was 8 years; however, 5 patients died within 13 months of initiation of treatment.

CONCLUSIONS

CD8 encephalitis in HIV-infected patients receiving cART is a clinical entity that should be added to the list of HIV complications.

Encephalitis with infiltration by CD8+ lymphocytes in HIV patients receiving combination antiretroviral treatment

We report the neuropathological findings in 10 HIV-infected patients treated by combination antiretroviral therapy who developed subacute encephalopathy of rapidly progressive onset. Brain biopsy showed encephalitic lesions variably associated with myelin loss and slight axonal damage. There was inconstant, weak expression of HIV protein p24; tests for other pathogens were negative. The most striking feature was diffuse, perivascular and intraparenchymal infiltration by CD8+ T-lymphocytes. Six patients improved after the treatment. Four had an unfavorable outcome and died within a year. Post-mortem in one case confirmed HIV leukoencephalitis with p24-positive multinucleated giant cells, associated with acute demyelinating encephalomyelitis (ADEM) in the cerebellum. There was diffuse infiltration by CD8+ lymphocytes; CD4+ cells were virtually absent. These cases may represent a specific clinicopathological entity, of which a few comparable cases have been already described. They can be included in the wide framework of immune reconstitution disease. Such syndromes have been described with opportunistic infections, but only seldom with HIV infection of the central nervous system (CNS). Our findings support the hypothesis that CD8+ cytotoxic lymphocytes can be harmful in immune reconstitution disease, particularly in the absence of CD4+ lymphocytes. CD8 cytotoxicity produces an acutization of a smoldering infection and/or an immunopathological reaction similar to ADEM.

A novel hereditary extensive vascular leukoencephalopathy mapping to chromosome 20q13

OBJECTIVE

The detection of a leukoencephalopathy is a frequent situation in neurologic practice. In a number of cases, the etiology remains obscure despite extensive investigations. We characterized the clinical, pathologic, and genetic features of a novel hereditary vascular leukoencephalopathy.

METHODS

After the observation of a similar leukoencephalopathy in 2 sisters, clinical, neuroimaging, and molecular genetics investigations were conducted in 21 of their consenting relatives. Pathologic data were obtained in one patient.

RESULTS

Fourteen members presented with significant white matter lesions at MRI examination, among whom only 5 individuals were symptomatic. The main clinical manifestations included gait disturbances, transient movement disorders, stroke, and cognitive dysfunction. The 9 remaining members aged from 26 to 60 years were asymptomatic. The MRI pattern was highly stereotyped with symmetric white matter hyperintensities worsening with patient's age. We mapped the gene involved in this condition on chromosome 20q13. Neuropathologic examination suggested that this leukoencephalopathy is underlaid by a cerebral arteriolopathy affecting small preterminal arterioles, clearly distinct from amyloid angiopathy and hypertension-related small-vessel disease.

CONCLUSIONS

These data establish that this family is affected by a novel autosomal dominant vascular leukoencephalopathy mapping to chromosome 20q13. This disease is characterized by a progressive and age-related hemispheric and brainstem leukoencephalopathy contrasting with the paucity and late onset of clinical symptoms in most of the cases.

Impact of hyperglycemia on neuropathological alterations during critical illness

CONTEXT

Although preventing excessive hyperglycemia during critical illness may provide clinical neuroprotection, it remains debated whether normoglycemia is without risk for the brain.

OBJECTIVE

To address this question, we compared the neuropathological alterations in microglia, astrocytes, and neurons, with uncontrolled hyperglycemia, moderately controlled hyperglycemia, and normoglycemia during human critical illness. We further investigated the time course in an animal model.

DESIGN AND SETTING

We analyzed brain specimens from patients who died in the intensive care unit and from critically ill rabbits randomized to hyper- or normoglycemia. PATIENTS/OTHER PARTICIPANTS: We compared 10 critically ill patients randomized to normoglycemia (104 ±9 mg/dl) or moderate hyperglycemia (173 ±32 mg/dl), and five patients with uncontrolled hyperglycemia (254 ±83 mg/dl) with 16 controls (out of hospital sudden deaths). Critically ill rabbits were randomized to hyperglycemia (315 ±32 mg/dl) or normoglycemia (85 ±13 mg/dl) and studied after 3 and 7 d.

INTERVENTIONS

Insulin was infused to control blood glucose.

MAIN OUTCOME MEASURES AND RESULTS

Patients with uncontrolled hyperglycemia showed 3.7-6-fold increased microglial activation, 54-95% reduced number and activation of astrocytes, more than 9-fold increased neuronal and glial apoptosis, and a 1.5-2-fold increase in damaged neurons in hippocampus and frontal cortex (all P ≤ 0.05). Most of these abnormalities were attenuated with moderate hyperglycemia and virtually absent with normoglycemia. Frontal cortex of hyperglycemic rabbits that had been critically ill for 3 d only revealed microglial activation, followed after 7 d by astrocyte and neuronal abnormalities similar to those observed in patients, all prevented by normoglycemia.

CONCLUSIONS

Preventing hyperglycemia with insulin during critical illness reduced neuropathological abnormalities, with microglial activation being the earliest preventable event. Whether these pathological findings associate with neurological outcome remains unknown.

Oxidative stress increases BACE1 protein levels through activation of the PKR-eIF2α pathway

Beta-site APP cleaving enzyme 1 (BACE1) is the rate limiting enzyme for accumulation of amyloid β (Aβ)-peptide in the brain in Alzheimer's disease (AD). Oxidative stress (OS) that leads to metabolic dysfunction and apoptosis of neurons in AD enhances BACE1 expression and activity. The activation of c-jun N-terminal kinase (JNK) pathway was proposed to explain the BACE1 mRNA increase under OS. However, little is known about the translational control of BACE1 in OS. Recently, a post-transcriptional increase of BACE1 level controlled by phosphorylation of eIF2α (eukaryotic translation initiation factor-2α) have been described after energy deprivation. PKR (double-stranded RNA dependant protein kinase) is a pro-apoptotic kinase that phosphorylates eIF2α and modulates JNK activation in various cellular stresses. We investigated the relations between PKR, eIF2α and BACE1 in AD brains in APP/PS1 knock-in mice and in hydrogen peroxide-induced OS in human neuroblastoma (SH-SY5Y) cell cultures. Immunoblotting results showed that activated PKR (pPKR) and activated eIF2α (peIF2α) and BACE1 levels are increased in AD cortices and BACE1 correlate with phosphorylated eIF2α levels. BACE1 protein levels are increased in response to OS in SH-SY5Y cells and specific inhibitions of PKR-eIF2α attenuate BACE1 protein levels in this model. Our findings provide a new translational regulation of BACE1, under the control of PKR in OS, where eIF2α phosphorylation regulates BACE1 protein expression.

Changes in CRH and ACTH synthesis during experimental and human septic shock

CONTEXT

The mechanisms of septic shock-associated adrenal insufficiency remain unclear. This study aimed at investigating the synthesis of corticotropin-releasing hormone (CRH) and vasopressin (AVP) by parvocellular neurons and the antehypophyseal expression of ACTH in human septic shock and in an experimental model of sepsis.

OBJECTIVE

To test the hypothesis that ACTH secretion is decreased secondarily to alteration of CRH or AVP synthesis, we undertook a neuropathological study of the antehypophyseal system in patients who had died from septic shock and rats with experimental faecal peritonitis.

METHODS

Brains obtained in 9 septic shock patients were compared to 10 nonseptic patients (controls). Parvocellular expression of AVP and CRH mRNA were evaluated by in situ hybridization. Antehypophyseal expression of ACTH, vasopressin V1b and CRH R1 receptors and parvocellular expression of iNOS in the PVN were evaluated by immunohistochemistry. The same experiments were carried out in a fecal peritonitis-induced model of sepsis. Data from septic rats with (n = 6) or without (n = 10) early death were compared to sham-operated (n = 8) animals.

RESULTS

In patients and rats, septic shock was associated with a decreased expression of ACTH, unchanged expression of V1B receptor, CRHR1 and AVP mRNA, and increased expression of parvocellular iNOS compared to controls. Septic shock was also characterized by an increased expression of CRH mRNA in rats but not in patients, who notably had a greater duration of septic shock.

CONCLUSION

The present study suggests that in humans and in rats, septic shock is associated with decreased ACTH synthesis that is not compensated by its two natural secretagogues, AVP and CRH. One underlying mechanism might be increased expression of iNOS in hypothalamic parvocellular neurons.

The PKR activator PACT is induced by Aβ: involvement in Alzheimer's disease

The neuropathological hallmarks of Alzheimer's disease (AD) include senile plaques made of Aβ peptide, neurofibrillary tangles containing hyperphosphorylated tau protein and neuronal loss. The pro-apoptotic kinase PKR can be activated by Aβ and can phosphorylate tau protein via GSK3β kinase activation. The activated form of PKR (pPKR) accumulates in affected neurons and could participate in neuronal degeneration in AD. The mechanism of abnormal PKR activation in AD is not elucidated but could be linked to the PKR activator PACT. PACT stainings, and levels were assessed in the brains of AD patients and in APP/PS1 knock-in transgenic mice and in cell cultures exposed to stresses. We showed that PACT and pPKR colocalizations are enhanced in AD brains. Their levels are increased and correlated in AD and APP/PS1 knock-in mice brains. In human neuroblastoma cells exposed to Aβ, tunicamycin or H2O2, PACT and pPKR concentrations are increased. PACT then PKR inhibitions indicate that PACT is upstream of PKR activation. Our findings demonstrate that PACT levels are enhanced in AD brains and could partly be caused by the action of Aβ. In addition, PACT participates in PKR activation. The PACT-PKR pathway represents a potential link between Aβ accumulation, PKR activation and tau phosphorylation.

Hyperglycaemia and apoptosis of microglial cells in human septic shock

Introduction

The effect of hyperglycaemia on the brain cells of septic shock patients is unknown. The objective of this study was to evaluate the relationship between hyperglycaemia and apoptosis in the brains of septic shock patients.

Methods

In a prospective study of 17 patients who died from septic shock, hippocampal tissue was assessed for neuronal ischaemia, neuronal and microglial apoptosis, neuronal Glucose Transporter (GLUT) 4, endothelial inducible Nitric Oxide Synthase (iNOS), microglial GLUT5 expression, microglial and astrocyte activation. Blood glucose (BG) was recorded five times a day from ICU admission to death. Hyperglycaemia was defined as a BG 200 mg/dL g/l and the area under the BG curve (AUBGC) > 2 g/l was assessed.

Results

Median BG over ICU stay was 2.2 g/l. Neuronal apoptosis was correlated with endothelial iNOS expression (rho = 0.68, P = 0.04), while microglial apoptosis was associated with AUBGC > 2 g/l (rho = 0.70; P = 0.002). Neuronal and microglial apoptosis correlated with each other (rho = 0.69, P = 0.006), but neither correlated with the duration of septic shock, nor with GLUT4 and 5 expression. Neuronal apoptosis and ischaemia tended to correlate with duration of hypotension.

Conclusions

In patients with septic shock, neuronal apoptosis is rather associated with iNOS expression and microglial apoptosis with hyperglycaemia, possibly because GLUT5 is not downregulated. These data provide a mechanistic basis for understanding the neuroprotective effects of glycemic control.

Congenital muscular dystrophy type 1D (MDC1D) due to a large intragenic insertion/deletion, involving intron 10 of the LARGE gene

Mutation of the LARGE gene is the rarest of the six known genetic causes of α-dystroglycanopathy. We report further a family with MDC1D due to a complex genomic rearrangement that was not apparent on standard sequencing of LARGE. Two sisters in a consanguineous family had moderate mental retardation and cerebellar malformations, together with dystrophic changes and markedly reduced α-dystroglycan glycosylation staining on muscle biopsy. There was homozygous linkage to the LARGE locus but sequencing of LARGE coding regions was normal. Analysis of LARGE cDNA showed an abnormal sequence inserted between exons 10 and 11, in most of the transcripts, predicted to introduce a premature stop codon. The abnormal sequence mapped to a spliced EST (DA935254) of unknown function, normally located at 100 kb centromeric of LARGE on chromosome 22q12.3. Quantitative PCR analysis of the EST and adjacent regions showed twice the normal copy number in patients' genomic DNA samples, consistent with a large intra-chromosomal duplication inserted into intron 10 of LARGE in a homozygous state. This insertion was associated with deletion of a central region of intron 10, but the exact break points of the deletion/duplication were not found, suggesting that an even more complex rearrangement may have occurred. The exact function of LARGE, a golgi protein, remains uncertain. POMT and POMGnT enzyme activities were normal in patients' lymphoblast cells, suggesting that defects in LARGE do not affect the initiation of O-mannosyl glycans.

Intra-aneurysmal thrombosis as a possible cause of delayed aneurysm rupture after flow-diversion treatment

BACKGROUND AND PURPOSE

FD technology enables reconstructive repair of otherwise difficult-to-treat intracranial aneurysms. These stentlike devices may induce progressive aneurysm thrombosis without additional implants and may initiate complete reverse vessel remodeling. The associated vascular biologic processes are as yet only partially understood.

MATERIALS AND METHODS

From 12 different centers, 13 cases of delayed postprocedural aneurysm rupture were recorded and analyzed. Symptom, aneurysm location and morphology, and the time elapsed from treatment until rupture were analyzed.

RESULTS

There were 10 internal carotid and 3 basilar artery aneurysms. Mean aneurysm diameter was 22 ± 6 mm. Eleven patients were symptomatic before treatment. A single FD was used for all saccular aneurysms, while fusiform lesions were treated by using multiple devices. A supplementary loose coiling of the aneurysm was performed in 1 patient only. Ten patients developed early aneurysm rupture after FD treatment (mean, 16 days; range, 2-48 days); in 3 patients, rupture occurred 3-5 months after treatment. In all cases, most of the aneurysm cavity was thrombosed before rupture. The biologic mechanisms predisposing to rupture under these conditions are reviewed and discussed

CONCLUSIONS

FDs alone may modify hemodynamics in ways that induce extensive aneurysm thrombosis. Under specific conditions, however, instead of reverse remodeling and cicatrization, aggressive thrombus-associated autolysis of the aneurysm wall may result in delayed rupture.

Modulation of tau phosphorylation by the kinase PKR: implications in Alzheimer's disease

Double-stranded RNA dependent kinase (PKR) is a pro-apoptotic kinase that controls protein translation. Previous studies revealed that activated PKR is increased in brains with Alzheimer's disease (AD). Glycogen Synthase Kinase Aβ (GSK-3β) is responsible for tau phosphorylation and controls several cellular functions also including apoptosis. The goal of this work was to determine if PKR could concurrently trigger GSK-3β activation, tau phosphorylation and apoptosis. In AD brains, both activated kinases co-localize with phosphorylated tau in neurons. In SH-SY5Y cell cultures, tunicamycin and Aβ(1-42) activate PKR, GSK-3β and induce tau phosphorylation and all these processes are attenuated by PKR inhibitors or PKR siRNA. Our results demonstrate that neuronal PKR co-localizes with GSK-3β and tau in AD brains and is able to modulate GSK-3β activation, tau phosphorylation and apoptosis in neuroblastoma cells exposed to tunicamycin or Aβ. PKR could represent a crucial signaling point relaying stress signals to neuronal pathways leading to cellular degeneration in AD.

Unilateral carotid granulomatous arteritis and Crohn's disease

Chronic idiopathic granulomatous arteritis of the large vessels - and, specifically, "Takayasu's arteritis" and "giant cell arteritis" - is an unusual condition that rarely leads to stroke and is only occasionally associated with Crohn's disease. We report here on a unique case of a 56-year-old man with a 25-year history of Crohn's disease who also had a 4-year history of recurrent right-sided ischaemic strokes and partial seizures, and a unilateral progressive retrograde occlusion of the right internal and common carotid arteries. Biopsies of the temporal and carotid arteries showed large-vessel granulomatous arteritis, with features of both giant cell and Takayasu's arteritis.

Vasopressin synthesis by the magnocellular neurons is different in the supraoptic nucleus and in the paraventricular nucleus in human and experimental septic shock

Impaired arginine vasopressin (AVP) synthesis and release by the neurohypophyseal system, which includes the neurohypophysis and magnocellular neurons of the paraventricular and supraoptic nuclei, have been postulated in septic shock, but changes in this system have never been assessed in human septic shock, and only partially experimentally. We investigated AVP synthesis and release by the neurohypophyseal system in 9 patients who died from septic shock and 10 controls, and in 20 rats with fecal peritonitis-induced sepsis and 8 sham-operation controls. Ten rats died spontaneously from septic shock, and the others were sacrificed. In patients with septic shock, as in rats that died spontaneously following sepsis induction, AVP immunohistochemical expression was decreased in the neurohypophysis and supraoptic magnocellular neurons, whereas it was increased in the paraventricular magnocellular neurons. No significant change was observed in AVP messenger RiboNucleic Acid (mRNA) expression assessed by in situ hybridization in either paraventricular or supraoptic magnocellular cells. This study shows that both in human and experimental septic shock, AVP posttranscriptional synthesis and transport are differently modified in the magnocellular neurons of the supraoptic and paraventricular nuclei. This may account for the inappropriate AVP release in septic shock and suggests that distinct pathogenic mechanisms operate in these nuclei.

Expression profiling of ependymomas unravels localization and tumor grade-specific tumorigenesis

BACKGROUND

Ependymomas derive from ependymal cells that cover the cerebral ventricles and the central canal of the spinal cord. The molecular alterations leading to ependymomal oncogenesis are not completely understood.

METHODS

The authors performed array-based expression profiling on a series of 34 frozen ependymal tumors with different localizations and histologic grades. Data were analyzed by nonsupervised and supervised clustering methods along with Gene Ontology and Pathway Analyzer tools.

RESULTS

Class discovery experiments indicated a strong correlation between profiles and tumor localization as well as World Health Organization (WHO) tumor grades. On the basis of supervised clustering, intracranial ependymomas were associated with high expression levels of Notch, Hedgehog, and bone morphogenetic protein pathway members. In contrast, most of the homeobox-containing genes manifested high expression in extracranial ependymomas. The results also revealed that WHO grade 2 ependymomas differed from WHO grade 3 ependymomas by genes implicated in Wnt/beta-catenin signaling, cell cycle, E2F transcription factor 1 destruction, angiogenesis, apoptosis, remodeling of adherens junctions, and mitotic spindle formation.

CONCLUSIONS

Taken together, the tumor localization-related gene sets mainly implicated in stem cell maintenance, renewal, and differentiation suggest the dysregulation of localized cancer stem cells during ependymoma development. The WHO grade differentiating pathways suggested that alteration of the Wnt/beta-catenin signaling pathway is a key event in the tumorigenesis of WHO grade 3 ependymomas. On the basis of the current data, the authors suggest a developmental scheme of ependymomas that integrates tumor localization and tumor grades, and that pinpoints new targets for the development of future therapeutic approaches.

Cerebral immunoglobulin light chain amyloid angiopathy-related hemorrhages

INTRODUCTION

Cerebral amyloid angiopathy (CAA) is a common cause of intracerebral hemorrhage (ICH) particularly in elderly patients. In CAA-related hemorrhages, amyloid deposits in the brain vessel walls mainly contain amyloid beta-protein (A-beta). Rarely other forms of amyloid substances have been reported in sporadic CAA-related hemorrhages.

METHODS

We report the case of a 44-year-old patient with recurrent ICH who had surgical evacuation of a large frontal hematoma. Following surgery, samples from the hematoma and adjacent cerebral cortex were obtained for histopathological examination.

RESULTS

Within the recent hemorrhage, a few arteriolar walls were thickened with an amyloid deposit that was immunostained for immunoglobulin (Ig) M and light chain lambda. In the wall of some vessels, around the amyloid deposits, as well as in the adjacent cerebral cortex, there was an infiltration by monotypic lymphocytes and plasma cells expressing IgM and light chain lambda. No amyloid deposition was found outside the hemorrhage. There was no evidence of multiple myeloma, B-cell malignancy, or systemic amyloidosis.

CONCLUSIONS

Recurrent ICH may be due to amyloid deposition of IgM lambda produced by monotypic proliferation of lymphocytes and plasma cells purely localized to the brain.

Bacterial infections

The organisms that produce bacterial infections of the nervous system in tropical regions are similar to those existing in the rest of the world. However, because of poor socio-economic conditions in the former areas, preventing the implementation of appropriate prophylactic and therapeutic measures, the incidence and course of these diseases may vary. In this paper the neuropathological appearances of the main bacterial diseases are reviewed and the main differences between those occurring in developed and developing countries emphasized. Despite great efforts by governments and communities, tuberculosis still remains a scourge in many countries and leprosy has not been eradicated from earth. Earlier optimism that antibiotics could finally put an end to syphilis have been dashed and the disease still persists. Moreover, the explosion of AIDS not only has produced a recrudescence of many of these diseases, but has also changed their clinical and pathological presentation.

[Neurenteric cyst of the posterior fossa. Case report and review of the literature]

Intracranial neurenteric cysts are rare entities. The term is currently used to describe epithelial cysts that are lined with a presumed endodermal-derived epithelium and are mostly located in the posterior fossa. Preoperative diagnosis is often difficult because of their clinical presentation, which may resemble a subarachnoid hemorrhage, and the radiological aspect, which can mimic vascular pathologies. We describe a posterior fossa neurenteric cyst in a 27-year-old woman, who presented with sudden headache as the only symptom and who was addressed to our hospital for subarachnoid hemorrhage. Diagnostic angiography was negative and MRI revealed a prepontine cystic lesion. The patient underwent a posterolateral approach on the right side, with subtotal resection of the lesion. We discuss the embryologic, diagnostic and therapeutic aspects of these cysts and review the literature.

Precision measurement of neutrino oscillation parameters with KamLAND

The KamLAND experiment has determined a precise value for the neutrino oscillation parameter Deltam21(2) and stringent constraints on theta12. The exposure to nuclear reactor antineutrinos is increased almost fourfold over previous results to 2.44 x 10(32) proton yr due to longer livetime and an enlarged fiducial volume. An undistorted reactor nu[over]e energy spectrum is now rejected at >5sigma. Analysis of the reactor spectrum above the inverse beta decay energy threshold, and including geoneutrinos, gives a best fit at Deltam21(2)=7.58(-0.13)(+0.14)(stat) -0.15+0.15(syst) x 10(-5) eV2 and tan2theta12=0.56(-0.07)+0.10(stat) -0.06+0.10(syst). Local Deltachi2 minima at higher and lower Deltam21(2) are disfavored at >4sigma. Combining with solar neutrino data, we obtain Deltam21(2)=7.59(-0.21)+0.21 x 10(-5) eV2 and tan2theta12=0.47(-0.05)+0.06.

An autopsy case of acute multiple sclerosis (Marburg's type) during pregnancy

We report a case of a 9-month pregnant woman who presented acute psychiatric and neurological symptoms with extensive involvement of the white matter on MRI and no oligoclonal bands on CSF examination. Despite high doses of intravenous steroids, plasmapheresis and immunosuppressive drugs, a fatal outcome (coma) was noted 8 months later. Neuropathological examination confirmed the diagnosis of Marburg's type of multiple sclerosis showing sharp-edged lesions of demyelination, giant astrocytes, numerous macrophages and little perivascular inflammation. We discuss the definition and limits of the Marburg entity with reference to acute disseminated encephalomyelitis, impact of pregnancy, unusual MRI features, neuropathology and treatment.

Neuropathologic contributions to understanding AIDS and the central nervous system

This historical review describes the evolution of the pathogenetic concepts associated with infection by the Human Immunodeficiency Virus (HIV), with emphasis on the pathology of the nervous system. Although the first descriptions of damage to the nervous system in the acquired immunodeficiency syndrome (AIDS) only appeared in 1982, the dramatic diffusion of the epidemic worldwide and the invariably rapidly fatal outcome of the disease, before the introduction of efficient treatment, generated from the beginning an enormous amount of research with rethinking on a number of pathogenetic concepts. Less than 25 years after the first autopsy series of AIDS patients were published and the virus responsible for AIDS was identified, satisfactory definition and classification of a number of neuropathological complications of HIV infection have been established, leading to accurate clinical radiological and biological diagnosis of the main neurological complications of the disease, which remain a major cause of disability and death in AIDS patients. Clinical and experimental studies have provided essential insight into the pathogenesis of CNS lesions and natural history of the disease. The relatively recent introduction of highly active antiretroviral therapy (HAART) in 1995-1996 has dramatically improved the course and prognosis of HIV disease. However, there remain a number of unsolved pathogenetic issues, the most puzzling of which remains the precise mechanism of neuronal damage underlying the specific HIV-related cognitive disorders (HIV dementia). In addition, although HAART has changed the course of neurological complications of HIV infection, new issues have emerged such as the lack of improvement or even paradoxical deterioration of the neurological status in treated patients. Interpretation of these latter data remains largely speculative partly because of the small number of neuropathological studies related to the beneficial consequence of this treatment.

Brain lesions in septic shock: a magnetic resonance imaging study

BACKGROUND

Understanding of sepsis-induced brain dysfunction remains poor, and relies mainly on data from animals or post-mortem studies in patients. The current study provided findings from magnetic resonance imaging of the brain in septic shock.

METHODS

Nine patients with septic shock and brain dysfunction [7 women, median age 63 years (interquartile range 61-79 years), SAPS II: 48 (44-56), SOFA: 8 (6-10)] underwent brain magnetic resonance imaging including gradient echo T1-weighted, fluid-attenuated inversion recovery (FLAIR), T2-weighted and diffusion isotropic images, and mapping of apparent diffusion coefficient.

RESULTS

Brain imaging was normal in two patients, showed multiple ischaemic strokes in two patients, and in the remaining patients showed white matter lesions at the level of the centrum semiovale, predominating around Virchow-Robin spaces, ranging from small multiple areas to diffuse lesions, and characterised by hyperintensity on FLAIR images. The main lesions were also characterised by reduced signal on diffusion isotropic images and increased apparent diffusion coefficient. The lesions of the white matter worsened with increasing duration of shock and were correlated with Glasgow Outcome Score.

CONCLUSION

This preliminary study showed that sepsis-induced brain lesions can be documented by magnetic resonance imaging. These lesions predominated in the white matter, suggesting increased blood-brain barrier permeability, and were associated with poor outcome.