Parker Solar Probe Observations of Solar Wind Energetic Proton Beams Produced by Magnetic Reconnection in the Near-Sun Heliospheric Current Sheet

We report observations of reconnection exhausts in the Heliospheric Current Sheet (HCS) during Parker Solar Probe Encounters 08 and 07, at 16 R _s and 20 R _s , respectively. Heliospheric current sheet (HCS) reconnection accelerated protons to almost twice the solar wind speed and increased the proton core energy by a factor of ∼3, due to the Alfvén speed being comparable to the solar wind flow speed at these near-Sun distances. Furthermore, protons were energized to super-thermal energies. During E08, energized protons were found to have leaked out of the exhaust along separatrix field lines, appearing as field-aligned energetic proton beams in a broad region outside the HCS. Concurrent dropouts of strahl electrons, indicating disconnection from the Sun, provide further evidence for the HCS being the source of the beams. Around the HCS in E07, there were also proton beams but without electron strahl dropouts, indicating that their origin was not the local HCS reconnection exhaust.

Mapping the contact area of the patellofemoral joint: the relationship between stability and joint congruence

AIMS

The aim of this study was to determine and compare the congruency of the articular surface contact area of the patellofemoral joint (PFJ) during both active and passive movement of the knee with the use of an MRI mapping technique in both the stable and unstable PFJ.

PATIENTS AND METHODS

A prospective case-control MRI imaging study of patients with a history of PFJ instability and a control group of volunteers without knee symptoms was performed. The PFJs were imaged with the use of an MRI scan during both passive and active movement from 0° through to 40° of flexion. The congruency through measurement of the contact surface area was mapped in 5-mm intervals on axial slices. In all, 40 patients were studied. The case group included 31 patients with symptomatic patellofemoral instability and the control group of nine asymptomatic volunteers. The ages were well matched between the case and control groups. The mean age was 25 years (16 to 42; sd 6.9) in the case group and 26 years (19 to 32; sd 5.1) in the control group. There were 19 female and 12 male patients in the case group.

RESULTS

The unstable PFJs were demonstrably less congruent than the stable PFJs throughout the range of knee movement. The greatest mean differences in congruency between unstable and stable PFJ's were observed between 11° and 20° flexion (1.73 cm² vs 4.00 cm²; p < 0.005).

CONCLUSION

The unstable PFJ is less congruent than the stable PFJ throughout the range of knee movement studied. This approach to mapping PFJ congruency produces a measurable outcome and will allow the assessment of pre- and postoperative results following surgical intervention. This may facilitate the design of new procedures for patients with PFJ instability. If a single axial series is to be obtained on MRI scan, the authors recommend 11° to 20° of tibiofemoral flexion, as this was shown to have the greatest difference in contact surface area between the case and control groups. Cite this article: Bone Joint J 2019;101-B:552-558.

Abstract P3-01-21: Circulating tumor cells of breast cancer origin identified by fluorescence in situ hybridization and may be an early predictor of therapy failure in early breast cancer

Background: Most modern methods of detecting circulating tumor cells (CTCs) involve identifying cells with epithelial markers. This approach presents challenges, as not all epithelial cells found in circulation originate from the tumor and not all CTCs express epithelial markers. We propose using a size-exclusion filtration system to enrich for CTCs in peripheral blood followed by fluorescence in situ hybridization (FISH) of the filtered cells to identify cells of tumor origin in the early-stage breast cancer patients. We further hypothesize that the presence of CTCs may be indicators of therapy failure in early-stage breast cancer patients.

Methods: Patients diagnosed with breast cancer (n = 9) were consented for CTC evaluation. Primary tumor DNA was analyzed by the Affymetrix OncoscanTM genome-wide microarray platform and investigated for somatic copy-number alterations (SCNAs). For each patient, two FISH probes were then identified for two regions of gain or a region of gain and a region of loss from the microarray results. Blood samples from patients were obtained before surgery, radiation therapy, endocrine therapy, and at 6-month or 1-year follow-up visits. Blood samples were filtered using ScreenCell® Cyto V2 devices, and FISH was performed. Cells were categorized as normal (diploid for all FISH probes), suspicious (single SCNA detected by FISH), or CTC (two SCNAs detected by FISH). Patients were identified as having CTCs present in their circulation when ≥2 CTCs were observed or when one CTC and &gt;15 suspicious cells were observed.

Results: The microarray data revealed that luminal A tumors ranged from 2-43 SCNAs; luminal B tumors ranged from 15-20 SCNAs; and ER+, PR+, HER2+ tumors ranged from 46-98 SCNAs. Although a correlation appears to exist between tumor genetic complexity and molecular subtype, the degree of complexity was highly varied within each subtype. We found that neither complexity of tumor profile, molecular subtype, nor stage could predict the presence of CTCs in patients.

Molecular SubtypeSCNAsCTCsSuspicious Cells OnlyLuminal A2-433/52/5Luminal B15-200/21/2ER+, PR+, HER2+46-982/20/2

In pre-surgical blood samples, we detected CTCs in 63% of patients with stage 1 disease and in 60% of patients with luminal A tumors, 0% of patients with luminal B tumors, and 100% of patients with triple-positive tumors.

StageCTCsSuspicious Cells OnlyIA/B5/82/8IIA0/11/1

Although limited in number, ongoing investigation revealed that one of our patients in early follow-up with a luminal A, stage IB tumor was identified to have persistent CTCs at 1-year after starting hormonal adjuvant therapy, suggesting residual tumor burden not detected by standard clinical modalities; this finding also suggests that this patient may be at highest risk for relapse and should be considered for additional therapies.

Conclusion: Size-exclusion filtration followed by FISH analysis can accurately identify CTCs in early-stage breast cancer patients. Tumor complexity, molecular subtype, and stage did not predict the presence of CTCs in circulation. Our method for CTC detection may be able to serve as a diagnostic tool for treatment failure.

Citation Format: Liu C, Althof PA, Maroni D, Stevens JM, Grabow CE, VanDyke AZ, Price JD, Sanmann JN, Thayer SP. Circulating tumor cells of breast cancer origin identified by fluorescence in situ hybridization and may be an early predictor of therapy failure in early breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-01-21.

Marine spatial planning makes room for offshore aquaculture in crowded coastal waters

Marine spatial planning (MSP) seeks to reduce conflicts and environmental impacts, and promote sustainable use of marine ecosystems. Existing MSP approaches have successfully determined how to achieve target levels of ocean area for particular uses while minimizing costs and impacts, but they do not provide a framework that derives analytical solutions in order to co-ordinate siting of multiple uses while balancing the effects of planning on each sector in the system. We develop such a framework for guiding offshore aquaculture (bivalve, finfish, and kelp farming) development in relation to existing sectors and environmental concerns (wild-capture fisheries, viewshed quality, benthic pollution, and disease spread) in California, USA. We identify > 250,000 MSP solutions that generate significant seafood supply and billions of dollars in revenue with minimal impacts (often < 1%) on existing sectors and the environment. We filter solutions to identify candidate locations for high-value, low-impact aquaculture development. Finally, we confirm the expectation of substantial value of our framework over conventional planning focused on maximizing individual objectives.

Marine spatial planning is used to co-ordinate multiple ocean uses, and is frequently informed by tradeoffs and composite metrics. Here, Lester et al. introduce an approach that plans for multiple uses simultaneously whilst balancing individual objectives, using a case study of aquaculture development in California.

Embryos whose polar bodies contain isolated reciprocal chromosome aneuploidy are almost always euploid

STUDY QUESTION

When a chromosome aneuploidy is detected in the first polar body and a reciprocal loss or gain of the same chromosome is detected in the second polar body, is the resulting embryo usually aneuploid for that chromosome?

SUMMARY ANSWER

When reciprocal aneuploidy occurs in polar bodies, the resulting embryo is usually normal for that chromosome, indicating that premature separation of sister chromatids (PSSC)—not non-disjunction—likely occurred in meiosis I.

WHAT IS KNOWN ALREADY

Single-nucleotide polymorphism-based microarray analysis can be used to accurately determine the chromosomal status of polar bodies and embryos. Sometimes, the only abnormality found is a reciprocal gain or loss of one or two chromosomes in the two polar bodies. Prediction of the status of the resulting embryo in these cases is problematic.

STUDY DESIGN, SIZE, DURATION

Blinded microarray analysis of previously diagnosed aneuploid embryos that had reciprocal polar body aneuploidy.

MATERIALS, SETTING, METHODS

IVF cycles were performed between 2008 and 2011 in patients aged 40 ± 3 years (range 35–47 years) with an indication for polar body-based aneuploidy screening. Thirty-five aneuploid vitrified Day 3 embryos were warmed, cultured to Day 5 and biopsied for microarray analysis. Predictions were made for the ploidy status of the embryo if PSSC or non-disjunction had occurred. The signal intensity for the aneuploid chromosome in the first polar body was compared between those that resulted in euploid and aneuploid embryos.

MAIN RESULTS AND THE ROLE OF CHANCE

Among 34 embryos with evaluable results, 31 were euploid on re-analysis. Of 43 chromosomes that had reciprocal aneuploidy in the polar bodies, 41 were disomic in the embryo, indicating that PSSC was likely to have occurred 95% (95% confidence interval 85–99%) of the time. The log 2 ratio signal intensity from the chromosomes that underwent non-disjunction, resulting in unbalanced embryos, were outliers when compared with those that underwent PSSC.

LIMITATIONS, REASONS FOR CAUTION

Although most embryos with reciprocal aneuploid polar bodies were euploid, it is unknown whether they maintain equivalent reproductive potential when transferred. Further study is needed to determine whether these embryos should be re-biopsied and considered for transfer.

WIDER IMPLICATIONS OF THE FINDINGS

This study is consistent with increasing evidence that PSSC is the primary cause of meiosis I errors in embryos from women of advanced reproductive age. Clinicians should be cautious in interpreting results from polar body aneuploidy screening, especially when only the first polar body is tested.

STUDY FUNDING/COMPETING INTEREST(S)

None.

Texture Analysis of Ultrasonic Images of Symptomatic Carotid Plaques can Identify Those Plaques Associated with Ipsilateral Embolic Brain Infarction

OBJECTIVES

The aim of our study was to determine the association between objective, computerised texture analysis of carotid plaque ultrasonic images and embolic CT-brain infarction in patients presenting with hemispheric neurological symptoms.

DESIGN

Cross-sectional study in patients with 50%-99% (ECST) carotid stenosis.

PATIENTS AND METHODS

Carotid plaque ultrasonic images (n=54, 26 with TIAs and 28 with stroke) obtained during carotid ultrasound were normalised and standardised for resolution and subsequently assessed visually for the presence of discrete echogenic or juxtaluminal echolucent components and overall echogenicity (plaque type). Using computer software, 51 histogram/textural features of the plaque outlines were calculated. Factor analysis was subsequently applied to eliminate redundant variables. Small cortical, large cortical and discrete subcortical infarcts on CT-brain scan were considered as being embolic.

RESULTS

Twenty-five cases (46%) had embolic infarcts. On logistic regression, grey-scale median (GSM), a measure of echolucency, spatial grey level dependence matrices (SGLDM) correlation and SGLDM information measure of correlation-1, measures of homogeneity were significant (p<0.05), but not grey level runlength statistics (RUNL) Run Percentage (RP), stenosis severity, type of symptoms or echolucent juxtaluminal components. Using ROC curves methodology, SGLDM information measure of correlation-1 improved the value of GSM in distinguishing embolic from non-embolic CT-brain infarction.

CONCLUSION

Computerised texture analysis of ultrasonic images of symptomatic carotid plaques can identify those that are associated with brain infarction, improving the results achieved by GSM alone. This methodology could be applied to prospective natural history studies of symptomatic patients not operated on or randomised trials of patients undergoing carotid angioplasty and stenting in order to identify high-risk subgroups for cerebral infarction.

Covalent cofactor attachment to proteins: cytochrome c biogenesis

Haem (Fe-protoporphyrin IX) is a cofactor found in a wide variety of proteins. It confers diverse functions, including electron transfer, the binding and sensing of gases, and many types of catalysis. The majority of cofactors are non-covalently attached to proteins. There are, however, some proteins in which the cofactor binds covalently and one of the major protein classes characterized by covalent cofactor attachment is the c-type cytochromes. The characteristic haem-binding mode of c-type cytochromes requires the formation of two covalent bonds between two cysteine residues in the protein and the two vinyl groups of haem. Haem attachment is a complex post-translational process that, in bacteria such as Escherichia coli, occurs in the periplasmic space and involves the participation of many proteins. Unexpectedly, it has been found that the haem chaperone CcmE (cytochrome c maturation), which is an essential intermediate in the process, also binds haem covalently before transferring the haem to apocytochromes. A single covalent bond is involved and occurs between a haem vinyl group and a histidine residue of CcmE. Several in vitro and in vivo studies have provided insight into the function of this protein and into the overall process of cytochrome c biogenesis.

Quantitative MRI measurement of superior cerebellar peduncle in progressive supranuclear palsy

BACKGROUND

Postmortem studies have shown atrophy of the superior cerebellar peduncle (SCP) to distinguish progressive supranuclear palsy (PSP) from other neurodegenerative diseases. It is not clear whether MRI-based measurements can differentiate this relative atrophy of the SCP during life.

METHODS

Volumetric MRI was acquired prospectively in 53 subjects: 19 with PSP, 10 with multiple system atrophy (MSA), 12 with Parkinson disease (PD), and 12 healthy controls. SCP volume was assessed by detailed quantitative volumetric measurement and independently by blinded visual rating of SCP atrophy.

RESULTS

The mean SCP volume, corrected for total intracranial volume, was lower in patients with PSP than controls (p < 0.001), patients with MSA (p = 0.001), and patients with PD (p = 0.003). There was an overlap between individual SCP volume measurements in the PSP subjects and the other groups. Neuroradiologic rating correctly identified PSP cases based on the presence of SCP atrophy with a sensitivity of 74% and a specificity of 94%.

CONCLUSIONS

The authors propose that together with other radiologic features of progressive supranuclear palsy (PSP) such as midbrain atrophy, a visual assessment of the superior cerebellar peduncle may help increase the clinical diagnostic accuracy in PSP.

Mapping the onset and progression of atrophy in familial frontotemporal lobar degeneration

BACKGROUND

Frontotemporal lobar degeneration (FTLD) may be inherited as an autosomal dominant disease. Studying patients "at risk" for developing FTLD can provide insights into the earliest onset and evolution of the disease.

METHOD

We carried out approximately annual clinical, MRI, and neuropsychological assessments on an asymptomatic 51 year old "at risk" family member from a family with FTLD associated with ubiquitin-positive and tau-negative inclusion bodies. We used non-linear (fluid) registration of serial MRI to determine areas undergoing significant regional atrophy at different stages of the disease.

RESULTS

Over the first 26 months of the study, the patient remained asymptomatic, but subsequently developed progressive speech production difficulties, and latterly severe orofacial dyspraxia, dyscalculia, frontal executive impairment, and limb dyspraxia. Regional atrophy was present prior to the onset of symptoms, and was initially centred on the left dorsolateral prefrontal cortex and the left middle frontal gyrus. Latterly, there was increasing asymmetric left frontal and parietal atrophy. Imaging revealed excess and increasing global atrophy throughout the study. Neuropsychological evaluation revealed mild intellectual impairment prior to the onset of these clinical symptoms; frontal executive and left parietal impairment subsequently emerged, culminating in widespread cognitive impairment. Fluid registered MRI allowed the emerging atrophy patterns to be delineated.

CONCLUSION

We have demonstrated the onset and progressive pattern of in vivo atrophy in familial FTLD using fluid registered MRI and correlated this with the clinical features. Fluid registered MRI may be a useful technique in assessing patterns of focal atrophy in vivo and demonstrating the progression of degenerative diseases.

Pathological substrate for regional distribution of increased atrophy rates in progressive supranuclear palsy

BACKGROUND

Most magnetic resonance imaging (MRI) studies of progressive supranuclear palsy (PSP) are cross-sectional and lack post mortem confirmation of the diagnosis. MRI features described previously in PSP correspond to regions of pathological involvement demonstrated in separate studies, but serial MRI with pathological follow up has not been undertaken.

OBJECTIVE

To investigate whether regions of increased atrophy rates demonstrated in PSP during life using fluid registered serial MRI correspond with pathological findings in confirmed PSP.

METHODS

A 59 year old male presented with a six month history of balance problems and dysarthria. He had a symmetrical, levodopa unresponsive akinetic-rigid syndrome with a vertical supranuclear gaze palsy. A clinical diagnosis of probable PSP was made. His disease progressed relentlessly and he died five years after onset. Two serial MRI scans undertaken during life were reviewed and fluid (non-linear) registration of the images carried out. Post mortem histopathological analysis of the brain was undertaken to definitively confirm the diagnosis and compare regional pathology with the serial imaging.

RESULTS

Fluid registration demonstrated greatest rates of atrophy in the brainstem and frontal cortex, in keeping with the distribution of pathology seen at autopsy.

CONCLUSION

Fluid registration of serial MRI allows the topography and rates of regional atrophy in PSP to be delineated in life. Atrophy patterns correlated well with regional pathological load. These observations suggest that serial MRI with registration may help differentiate PSP from clinically similar conditions and supports its use as a surrogate marker of disease progression.

The regulation of integrin-linked kinase in human platelets: evidence for involvement in the regulation of integrin alpha 2 beta 1

BACKGROUND

Activation of the platelet integrin alpha 2 beta 1 is closely regulated due to the high thrombogenicity of its ligand. As a beta 1 interacting kinase, ILK represents a candidate intracellular regulator of alpha 2 beta 1 in human platelets.

OBJECTIVES

We investigated the regulation of ILK in human platelets and the role of ILK in regulating alpha 2 beta 1 activation in HEL cells, a megakaryocytic cell line.

METHODS

An in-vitro kinase assay was used to determine the effect of platelet agonists on ILK kinase activity together with the contribution of PI3K and PKC on ILK activation. Interaction of ILK with beta 1-integrin subunits was investigated by coimmunoprecipitation and the role of ILK in regulating alpha 2 beta 1 function assessed by overexpression studies in HEL cells.

RESULTS

We report that collagen and thrombin modulate ILK kinase activity in human platelets in an aggregation-independent manner. Furthermore, ILK activity is dually regulated by PI3K and PKC in thrombin-stimulated platelets and regulated by PI3K in collagen-stimulated cells. ILK associates with the beta 1-integrin subunits immunoprecipitated from platelet cell lysates, an association which increased upon collagen stimulation. Overexpression of ILK in HEL cells enhanced alpha 2 beta 1-mediated adhesion whereas overexpression of kinase-dead ILK reduced adhesion, indicating a role for this kinase in the positive regulation of alpha 2 beta 1.

CONCLUSIONS

Our findings that ILK regulates alpha 2 beta 1 in HEL cells, is activated in platelets and associates with beta 1-integrins, raise the possibility that it may play a key role in adhesion events upon agonist stimulation of platelets.

Diagnosis of aspergillus peritonitis in a renal dialysis patient by PCR and galactomannan detection

This report describes the use of the polymerase chain reaction (PCR) and galactomannan detection to detect aspergillus in the continuous ambulatory peritoneal dialysis (CAPD) fluid and blood of a patient with multiple myeloma on CAPD and immunosuppressive treatment. Diagnosis of aspergillosis was initially made by conventional culture of CAPD fluid, but the PCR and galactomannan assays also detected aspergillus DNA and antigen in the blood, respectively. This suggests that the PCR and galactomannan assays, previously suggested as useful in the management of invasive fungal infections in neutropenic haematological patients, may be suitable for application to a broad range of clinical situations and sample types.

The effect of a symptom related "gating policy" on ANCA requests in routine clinical practice

BACKGROUND

Most positive antineutrophil cytoplasmic antibody (ANCA) results are associated with non-vasculitic conditions, and guidelines have been proposed for the judicious use of this test. The outcome of applying similar guidelines in a routine laboratory is reported.

METHODS

All immunology requests (6500) over six months were selected, and those requesting ANCA were studied for the appropriateness of the clinical data supporting the request, the presence of ANCA in those samples tested, and the final diagnosis. Antibodies were detected by indirect immunofluorescence.

RESULTS

ANCA testing was requested in 287 samples. Application of a "gating policy", which refuses analysis on requests that are not supported by clinical data suggestive of systemic vasculitis, made clinicians more selective about the patients for whom they requested ANCA testing. The percentage of "appropriate" screens for systemic vasculitis was relatively high (212 of 287 requests: 72.5%). Only one of the remainder, for whom ANCA testing was initially refused, developed an ANCA related systemic vasculitis in the two years after the study, but the delay in reporting her positive ANCA was only two days. Most of the samples tested were negative (155 of 212), but most (42 of 57) of the patients with positive ANCA results were found to have a systemic vasculitis.

CONCLUSIONS

A gating policy to select requests supported by clinical data suggestive of systemic vasculitis makes ANCA testing more clinically relevant and cost effective. Studies where guidelines can be proposed and their effects measured are important in the light of clinical governance and evidence based medicine.

The Asymptomatic Carotid Stenosis and Risk of Stroke (ACSRS) study. Aims and results of quality control

AIM

The results of the Asymptomatic Carotid Atherosclerosis Study (ACAS) study have provided the first scientific evidence that in patients with asymptomatic carotid stenosis greater than 60% carotid endarterectomy reduces the risk of stroke from 2% to 1% per year. The implications are that approximately 20 operations need to be performed in order to prevent 1 stroke in 5 years. The aims of the Asymptomatic Carotid Stenosis and Risk of Stroke (ACSRS) study are to identify a subgroup or subgroups at a risk for stroke higher than 4% and a group at a risk for stroke less than 1% per year using systemic and local risk factors (plaque characterization) in addition to the degree of stenosis. The aim of this paper is to present the protocol and the results of the quality control.

METHODS

The ACSRS is a multicentre natural history study of patients with asymptomatic internal carotid diameter stenosis greater than 50% in relation to the bulb. The degree of stenosis is graded using multiple established ultrasonic duplex criteria. In addition, ultrasonic plaque characterization is performed and clinical risk factors and medications are recorded. Training is provided centrally. All carotid ultrasound examinations are recorded on video-tape which together with CT-brain scans and ECG are analysed at the coordinating centre with feedback information to partner centres.

RESULTS

The video recordings and analysis of data centrally with feed back information have provided quality control with a significant improvement not only in the completion of data forms but also in the grading of internal carotid stenosis and plaque recordings using ultrasound.

CONCLUSION

The high level of quality of data collected will add credibility to the results of the ACSRS study and may eventually promote the development of international standards of plaque imaging and characterization.

Quercetin inhibits collagen-stimulated platelet activation through inhibition of multiple components of the glycoprotein VI signaling pathway

BACKGROUND

The regulation of platelet function by pharmacological agents that modulate platelet signaling has proven a successful approach to the prevention of thrombosis. A variety of molecules present in the diet have been shown to inhibit platelet activation, including the antioxidant quercetin.

OBJECTIVES

In this report we investigate the molecular mechanisms through which quercetin inhibits collagen-stimulated platelet aggregation.

METHODS

The effect of quercetin on platelet aggregation, intracellular calcium release, whole cell tyrosine phosphorylation and intracellular signaling events including tyrosine phosphorylation and kinase activity of proteins involved in the collagen-stimulated glycoprotein (GP) signaling pathway were investigated.

RESULTS

We report that quercetin inhibits collagen-stimulated whole cell protein tyrosine phosphorylation and intracellular mobilization of calcium, in a concentration-dependent manner. Quercetin was also found to inhibit various events in signaling generated by the collagen receptor GPVI. This includes collagen-stimulated tyrosine phosphorylation of the Fc receptor gamma-chain, Syk, LAT and phospholipase Cgamma2. Inhibition of phosphorylation of the Fc receptor gamma-chain suggests that quercetin inhibits early signaling events following stimulation of platelets with collagen. The activity of the kinases that phosphorylate the Fc receptor gamma-chain, Fyn and Lyn, as well as the tyrosine kinase Syk and phosphoinositide 3-kinase was also inhibited by quercetin in a concentration-dependent manner, both in whole cells and in isolation.

CONCLUSIONS

The present results provide a molecular basis for the inhibition by quercetin of collagen-stimulated platelet activation, through inhibition of multiple components of the GPVI signaling pathway, and may begin to explain the proposed health benefits of high quercetin intake.

Transient ischaemic attacks are associated with increased rates of global cerebral atrophy

OBJECTIVES

To determine whether patients presenting with a first transient ischaemic attack (TIA) subsequently show increased rates of brain atrophy compared with age matched controls; and to assess potential risk factors for brain atrophy in this group.

METHODS

60 patients with a first, isolated TIA and 26 age and sex matched controls were recruited. None had evidence of cognitive impairment. Vascular risk factors were treated appropriately. All subjects had volumetric imaging at the start of the study and one year later, when they were clinically reassessed. TIA patients also had serial dual echo brain imaging. Rates of whole brain atrophy were calculated from the registered volumetric scans, as was the incidence of new ischaemic lesions. In the TIA group, the degree of white matter disease was assessed. Atrophy rates and blood pressure were compared between patients and controls.

RESULTS

22 patients (37%) developed new "clinically silent" infarcts during follow up. The mean (SD) annualised percentage atrophy rate in the TIA group was significantly higher than in the controls, at 0.82 (0.39)% v 0.33 (0.3)% (p < 0.0001). In the TIA group, diastolic blood pressure (p = 0.004) and white matter disease severity (p < 0.001) were correlated with cerebral atrophy rate. Increased white matter disease was found in patients in whom new ischaemic lesions developed (p < 0.001).

CONCLUSIONS

Patients presenting with a first TIA have excess global brain atrophy compared with age matched controls over the subsequent year. Increased atrophy rates following a TIA may be directly or indirectly related to increasing white matter disease and diastolic hypertension. Future studies should assess whether this atrophy inevitably leads to cognitive decline, and whether aggressive treatment of risk factors for cerebrovascular disease (particularly hypertension) after a TIA can influence outcome.

Cerebellar volumes in newly diagnosed and chronic epilepsy

Cerebellar atrophy is assumed to be a common finding in patients suffering from epilepsy. Anticonvulsants as well as seizure activity itself have been considered to be responsible for it but many studies have addressed these questions in specialised centres for epilepsy thus having a referral bias towards patients with severe epileptic syndromes. The purpose of this study was: 1. To develop a quantitative method on 3D-MRI data to achieve volume or planimetric measurements (of cerebrum, cerebellum and cerebellar substructures). 2. To investigate the prevalence of cerebellar atrophy (and substructure atrophy) in a prospectively investigated population-based cohort of patients with newly diagnosed and chronic epilepsy. 3. To quantify cerebellar atrophy in clinic-based patients, who had had atrophy previously diagnosed on routine visual MRI assessment. 4. To correlate the measures of atrophy with clinical features in both patient groups. A total of 57 patients with either newly diagnosed or chronic active epilepsy and 36 control subjects were investigated with a newly developed semiautomated method for cerebral as well as cerebellar volume measurements and substructure planimetry, corrected for intracranial volume. We did not find any significant atrophy in the population-based cohort of patients with newly diagnosed epilepsy or with chronic epilepsy. Visually diagnosed cerebellar atrophy was mostly confirmed and quantified by volumetric analysis. The clinical data suggested a correlation between cerebellar atrophy and the duration of the seizure disorder and also the total number of lifetime seizures experienced and the frequency of generalised tonic-clonic seizures per year. Volumetry on 3D-MRI yields reliable quantitative data which shows that cerebellar atrophy might be common in severe and/or longstanding epilepsy but not necessarily in unselected patient groups. The results do not support the proposition that cerebellar atrophy is a predisposing factor for epilepsy but rather are consistent with the view that cerebellar atrophy is the aftermath of epileptic seizures or anticonvulsant medication.

Anterior commissure absence without callosal agenesis: a new brain malformation

The authors report a novel human brain malformation characterized by the absence of the anterior commissure without callosal agenesis, but associated with gross unilateral panhemispheric malformation incorporating subependymal heterotopia, subcortical heterotopia, and gyral abnormalities including temporal malformation and polymicrogyria. In contrast, a normal anterior commissure was found in 125 control subjects and in 113 other subjects with a range of brain malformations.

Ultra-fast low-angle rapid acquisition and relaxation enhancement (UFLARE) in patients with epilepsy

MRI is an important diagnostic tool in patients with epilepsy, but patient motion during long scans may result in image artefacts. We studied the utility of an ultra-fast MR sequence in patients with epilepsy. Ultra-fast low-angle rapid acquisition and relaxation enhancement (UFLARE) images were acquired for 100 consecutive patients and nine control subjects. Scans were compared with routine T2-weighted spin echo images for signal-to-noise ratio, contrast, and conspicuity, followed by a blind review of lesion detectability. UFLARE scans were also acquired for 15 patients who moved during conventional scans. All UFLARE scans had lower signal-to-noise ratios and lower contrast than the T2-weighted images. Compared with T1- and T2-weighted, PD and FLAIR images, 86% of hippocampal sclerosis (HS), 92% of large but only 24% of small white-matter lesions were detected on the blind review of the UFLARE images. Reduced motion artefacts were seen on the UFLARE images in all 15 patients who moved during the conventional scans, and in three patients UFLARE was the only sequence we were able to obtain. Despite the lower lesion detectability for smaller lesions, the use of an ultra-fast MRI sequence such as UFLARE may be very useful in patients who are not able to co-operate during conventional MRI examinations, if a general anaesthetic is to be avoided.

New inhibitors of iron-containing nitrile hydratases

There is growing evidence in the literature emphasizing the significance of the post-translational modification of cysteine thiols to sulfenic acids (SOH), which have been found in a number of proteins. Crystallographic and mass spectrometric evidence has shown the presence of this group in an inactive form of the industrially important enzyme nitrile hydratase (NHase). This oxidized cysteine is unique in that it forms part of the coordination sphere of the low-spin iron III at the active site of the enzyme. The presence of this unstable sulfenic group in the active form of NHase is the subject of some controversy. To try to detect this function in NHase, we have studied the inhibitory effect on nitrile hydration of reagents known to react with sulfenic acids. Two NHases were studied, namely, Rhodococcus rhodochrous R312 NHase and Comamonas testosteroni NI1 NHase, and the reagents used were meta-chlorocarbonyldicyano-phenylhydrazone (m-ClCP), 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl), and 2-nitro-5-thiocyanato-benzoic acid (NTBA). Following this approach we report three novel inhibitors of NHases. In addition, we report thiocyanate reagents that can be used to monitor NHase activity spectroscopically.

Imaging of onset and progression of Alzheimer's disease with voxel-compression mapping of serial magnetic resonance images

BACKGROUND

Early diagnosis and monitoring of the progression of Alzheimer's disease is important for the development of therapeutic strategies. To detect the earliest structural brain changes, individuals need to be studied before symptom onset. We used an imaging technique known as voxel-compression mapping to localise progressive atrophy in patients with preclinical Alzheimer's disease.

METHODS

Four symptom-free individuals from families with early-onset Alzheimer's disease with known autosomal dominant mutations underwent serial magnetic resonance imaging (MRI) over 5-8 years. All four became symptomatic during follow-up. 20 individuals with a clinical diagnosis of probable Alzheimer's disease and 20 control participants also underwent serial MR imaging. A non-linear fluid matching algorithm was applied to register repeat scans onto baseline imaging. Jacobian determinants were used to create the voxel-compression maps.

FINDINGS

Progressive atrophy was revealed in presymptomatic individuals, with posterior cingulate and neocortical temporoparietal cortical losses, and medial temporal-lobe atrophy. In patients with known Alzheimer's disease, atrophy was widespread apart from in the primary motor and sensory cortices and cerebellum, reflecting the clinical phenomenology.

INTERPRETATION

Voxel-compression maps confirmed early involvement of the medial temporal lobes, but also showed posterior cingulate and temporoparietal cortical losses at presymptomatic stage. This technique could be applied diagnostically and used to monitor the effects of therapeutic intervention.

PAX6 haploinsufficiency causes cerebral malformation and olfactory dysfunction in humans

PAX6 is widely expressed in the central nervous system. Heterozygous PAX6 mutations in human aniridia cause defects that would seem to be confined to the eye. Magnetic resonance imaging (MRI) and smell testing reveal the absence or hypoplasia of the anterior commissure and reduced olfaction in a large proportion of aniridia cases, which shows that PAX6 haploinsuffiency causes more widespread human neuro developmental anomalies.

Paroxysmal alternating skew deviation and nystagmus after partial destruction of the uvula

A patient with suspected brain stem glioma involving the area of the left vestibular nuclei and cerebellar peduncle, developed paroxysmal alternating skew deviation and direction changing nystagmus after biopsy of the inferior cerebellar vermis resulting in destruction of the uvula. Between attacks she had right over left skew deviation with asymptomatic right beating horizontal nystagmus. Slow phases of the resting nystagmus showed increasing velocity, similar to congenital nystagmus. At intervals of 40-50 seconds, paroxysmal reversal of her skew deviation occurred, accompanied by violent left beating horizontal torsional nystagmus lasting 10-12 seconds and causing severe oscillopsia. It is proposed that this complex paroxysmal eye movement disorder results from (1) a lesion in the left vestibular nuclei causing right over left skew and right beating resting nystagmus and (2) a disruption of cerebellar inhibition of vestibular nuclei, causing alternating activity in the vestibular system with intermittent reversal of the skew deviation and paroxysmal nystagmus towards the side of the lesion.

Brain CT infarction in patients with carotid atheroma. Does it predict a future event?

BACKGROUND

The aim of the present study was to investigate the predictive value for subsequent stroke of different patterns of brain CT infarction in patients with carotid atheroma.

METHODS

Prospective study on 138 patients, with 138 carotid plaques, having, on presentation, a greater than 50 percent stenosis on duplex scanning and associated with an ipsilateral (to the plaque) amaurosis fugax (AF), hemispheric transient ischaemic attack (HTIA) or which were asymptomatic. This carotid artery defined the side of interest. All patients had a brain CT scan on presentation and subsequently were followed for a period of 1-5 years (mean 3.14). The baseline CT neurovascular findings on the side of interest were classified as pattern A (discrete subcortical and cortical infarctions), pattern B (haemodynamic infarctions, widespread white matter lesions, basal ganglia infarctions and lacunae) and normal CT.

RESULTS

On follow-up, 5/27 (18.5 percent) of patients with pattern A, 4/38 (10.5 percent) with pattern B and 3/73 (4.1 percent) with normal CT appearance developed stroke in the hemisphere of interest (Cox regression: p=0.02).

CONCLUSIONS

Pattern A confers an unfavourable prognosis in patients with carotid atheroma who are either asymptomatic or presented with amaurosis fugax or hemispheric transient ischaemic attacks.

Autopsy-confirmed familial early-onset Alzheimer disease caused by the l153V presenilin 1 mutation

BACKGROUND

Three affected individuals are described from a small English kindred with early-onset autosomal dominant familial Alzheimer disease (FAD) caused by a leucine-to-valine change at codon 153 (L153V) of the presenilin 1 (PSEN1) gene.

METHODS

Clinical information on the pedigree was collected directly from family members and from hospital records. Samples of DNA were screened by means of direct sequencing of all coding exons of PSEN1. One patient underwent neuropathological examination.

RESULTS

Mean age at onset of symptoms was 35.3 years (95% confidence interval [CI], 34.6-36.0 years); at death, 44.0 years (95% CI, 39.1-48.9 years). Mean duration of illness was 8.3 years (95% CI, 4.7-11.9 years). Myoclonus was a late feature in 1 patient; seizures were not reported in any subjects. Spastic paraparesis and extrapyramidal signs were absent. The neuropsychometric profile of 1 patient showed relatively preserved naming skills in the setting of global cognitive deficits. Results of neuropathological examination demonstrated the signature lesions of Alzheimer disease and the presence of occasional cortical Lewy bodies.

CONCLUSIONS

The PSEN1 L153V mutation lies in the main mutation cluster of PSEN1 in the second transmembrane domain. It causes early-onset FAD with clinical features similar to those of other reported FAD pedigrees.

Patterns of temporal lobe atrophy in semantic dementia and Alzheimer's disease

Volumetric magnetic resonance imaging analyses of 30 subjects were undertaken to quantify the global and temporal lobe atrophy in semantic dementia and Alzheimer's disease. Three groups of 10 subjects were studied: semantic dementia patients, Alzheimer's disease patients, and control subjects. The temporal lobe structures measured were the amygdala, hippocampus, entorhinal cortex, parahippocampal gyrus, fusiform gyrus, and superior, middle, and inferior temporal gyri. Semantic dementia and Alzheimer's disease groups did not differ significantly on global atrophy measures. In semantic dementia, there was asymmetrical temporal lobe atrophy, with greater left-sided damage. There was an anteroposterior gradient in the distribution of temporal lobe atrophy, with more marked atrophy anteriorly. All left anterior temporal lobe structures were affected in semantic dementia, with the entorhinal cortex, amygdala, middle and inferior temporal gyri, and fusiform gyrus the most severely damaged. Asymmetrical, predominantly anterior hippocampal atrophy was also present. In Alzheimer's disease, there was symmetrical atrophy of the entorhinal cortex, hippocampus, and amygdala, with no evidence of an anteroposterior gradient in the distribution of temporal lobe or hippocampal atrophy. These data demonstrate that there is a marked difference in the distribution of temporal lobe atrophy in semantic dementia and Alzheimer's disease. In addition, the pattern of atrophy in semantic dementia suggests that semantic memory is subserved by anterior temporal lobe structures, within which the middle and inferior temporal gyri may play a key role.

Neurology in ancient faces

BACKGROUND

Clinical paleoneurology is almost non-existent, but recognition of neurological diseases in ancient people might be possible by scrutinising portraits apparently representing people as they appeared in life.

METHODS

About 200 mummy portraits painted in colour at the beginning of the first millennium were examined. Thirty two skulls excavated at Hawara in the Fayum (northern Egypt), where most of the portraits were found were measured, and nine caliper measures on each side of the skulls were taken. The right/left ratios were statistically analyzed by analysis of variance (ANOVA). One skull was subjected to 3D CT scanning and transilluminated.

RESULTS

Two patients were found with progressive facial hemiatrophy (Parry-Romberg syndrome), three with deviations of the visual axes (tropia) and one with oval pupils (corectopia).

CONCLUSIONS

Clinical paleoneurology is possible in the absence of a living nervous system. The patients probably had focal epilepsy, hemiplegic migraine, and autonomic nervous system dysfunction.

Carotid plaque echogenicity and types of silent CT-brain infarcts. Is there an association in patients with asymptomatic carotid stenosis?

BACKGROUND

The aim of this study was to identify the differences in echogenicity and the degree of stenosis of asymptomatic carotid plaques associated with different types of ipsilateral silent CT-brain infarcts.

METHODS

Some 273 asymptomatic carotid plaques (218 patients) causing 50 to 99% stenosis were studied with high-resolution ultrasound. B-mode images were digitised and normalised by assigning certain grey values to blood and adventitia. The grey scale median (GSM) of the plaque in the normalised image was used to quantify echogenicity. Every patient had a CT-brain scan which an independent neuroradiologist read. The presence of 1) non-lacunar and 2) lacunar silent CT-brain infarcts ipsilateral to the carotid plaque was noted.

RESULTS

The mean GSM of plaques associated with non-lacunar silent CT-brain infarcts was 19.6, of plaques associated with lacunar infarcts was 35.5 and of those associated with no infarcts was 32 (p=0.008, ANOVA). The mean degree of stenosis was 79%, 72% and 73% respectively (p = 0.1, ANOVA). Plaque echogenicity (p = 0.007) and not the degree of stenosis (p = 0.07) predicted the presence of non-lacunar silent CT-brain infarcts (logistic regression).

CONCLUSIONS

Carotid bifurcation plaques, which are associated with non-lacunar silent CT-brain infarcts, are significantly more hypoechoic than those associated with lacunar or no infarcts. Plaques associated with lacunar silent infarcts and no infarcts have the same echogenicity and degree of stenosis. These findings suggest an embologenic mechanism of non-lacunar silent CT-brain infarcts that may have prognostic implications in patients with asymptomatic carotid stenosis. Prospective studies of asymptomatic carotid stenosis should assess the significance of 1) plaque echogenicity and 2) the presence of different types of silent CT-brain infarcts and atheroembolic stroke.

How broad is the phenotype of Hallervorden-Spatz disease?

Magnetic resonance imaging (MRI) has enabled ante mortem diagnosis of Hallervorden Spatz disease (HSD). Childhood-onset cases are the most common type and usually present with progressive dystonia and dementia. The duration of illness is 15 to 20 years, leading to death. Presentation in adulthood and infancy have also been reported, however again the progression is usually inexorable. We present a 30-year-old woman who developed cognitive and motor developmental delay from the age of 8 months. There was further cognitive decline in her late teenage years with seizures and then more recent motor decline with dystonia. The imaging appearance was of iron deposition in the globus pallidus and substantia nigra leading to a diagnosis of HSD. The increased availability of MRI has allowed more cases of HSD to be diagnosed in life but as our case illustrates classification of the disease may need to be further examined.

Patterns of brain computed tomography infarction and carotid plaque echogenicity

PURPOSE

It was suggested that in the absence of cardioembolism the discrete subcortical and cortical infarctions on brain computed tomography (CT) are most likely associated with carotid atheroma, whereas the hemodynamic infarctions, diffuse widespread white matter lesions, lacunae and basal ganglia infarctions are most likely associated with other pathologic conditions. The aim of this study was to determine the ultrasonic characteristics of carotid plaques and the degree of stenosis that were associated with the different brain CT infarction patterns and normal CT (pattern A, discrete subcortical and cortical infarctions; pattern B, hemodynamic infarctions, diffuse widespread white matter lesions, lacunae and basal ganglia infarctions).

METHODS

Four hundred nineteen carotid plaques (315 patients), producing 50% to 99% stenosis on duplex scanning, were studied. These plaques were imaged on duplex scanning, captured, digitized, and normalized (standardized) in a computer. Subsequently, their gray scale median (GSM) was evaluated to distinguish quantitatively the hypoechoic (low GSM) from the hyperechoic (high GSM) plaques. The brain CT infarction patterns of A, B, or normal CT on the ipsilateral hemisphere were noted.

RESULTS

The pattern A brain CT infarction was associated with carotid plaques having median GSM of 11 and median degree of stenosis of 80%, as contrasted with pattern B (median GSM, 28.5; median degree of stenosis, 75%) or normal CT (median GSM, 22; median degree of stenosis, 75%) (Kruskal-Wallis test, P <.001 for the GSM and P =.002 for the degree of stenosis). In the logistic regression analysis only the GSM and not the degree of stenosis distinguished the plaques associated with the three CT patterns.

CONCLUSIONS

The pattern A brain CT infarction was associated with hypoechoic plaques suggesting an involvement of extracranial carotid artery embolization, whereas the pattern B was associated with hyperechoic plaques suggesting an involvement of other mechanisms (hemodynamic, intracranial small and large vessel disease).

Equilibrium folding of dimeric class mu glutathione transferases involves a stable monomeric intermediate

The conformational stabilities of two homodimeric class mu glutathione transferases (GSTM1-1 and GSTM2-2) were studied by urea- and guanidinium chloride-induced denaturation. Unfolding is reversible and structural changes were followed with far-ultraviolet circular dichroism, tryptophan fluorescence, enzyme activity, chemical cross-linking, and size-exclusion chromatography. Disruption of secondary structure occurs as a monophasic transition and is independent of protein concentration. Changes in tertiary structure occur as two transitions; the first is protein concentration dependent, while the second is weakly dependent (GSTM1-1) or independent (GSTM2-2). The second transition corresponds with the secondary structure transition. Loss in catalytic activity occurs as two transitions for GSTM1-1 and as one transition for GSTM2-2. These transitions are dependent upon protein concentration. The first deactivation transition coincides with the first tertiary structure transition. Dimer dissociation occurs prior to disruption of secondary structure. The data suggest that the equilibrium unfolding/refolding of the class mu glutathione transferases M1-1 and M2-2 proceed via a three-state process: N(2) <--> 2I <--> 2U. Although GSTM1-1 and GSTM2-2 are homologous (78% identity/94% homology), their N(2) tertiary structures are not identical. Dissociation of the GSTM1-1 dimer to structured monomers (I) occurs at lower denaturant concentrations than for GSTM2-2. The monomeric intermediate for GSTM1-1 is, however, more stable than the intermediate for GSTM2-2. The intermediates are catalytically inactive and display nativelike secondary structure. Guanidinium chloride-induced denaturation yields monomeric intermediates, which have a more loosely packed tertiary structure displaying enhanced solvent exposure of its tryptophans and enhanced ANS binding. The three-state model for the class mu enzymes is in contrast to the equilibrium two-state models previously proposed for representatives of classes alpha/pi/Sj26 GSTs. Class mu subunits appear to be intrinsically more stable than those of the other GST classes.

HER-2/neu assessment in breast cancer by immunohistochemistry and fluorescence in situ hybridization: comparison of results and correlation with survival

BACKGROUND

HER-2/neu immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) results guide breast cancer therapy; however, few studies compared the results and no published studies have correlated them with patient outcome.

METHODS AND RESULTS

We compared results, cost, and turnaround time in 117 archival, invasive breast carcinomas and compared 50-month survival in 65 of these cases using commercial HER-2/neu IHC and FISH assays. Twenty-one of 112 FISH (19%) and 33 of 117 IHC cases (28%) were positive. Concordance was high overall (88%; 98 of 112 cases) and in IHC 3+ cases (88%; 14 of 16 cases) but low in IHC 2+ cases (35%; six of 17 cases). Survival correlated with IHC results in 3+ cases (P =.02) and FISH cases with signal ratio greater than 4.0 (P =.03), but not in IHC 2+ cases (P=.7). Cost and turnaround time were greater for FISH.

CONCLUSION

IHC is appropriate for initial HER-2/neu assessment; however, patients with tumors scored less than 3+, particularly those interpreted as 2+, would benefit from FISH to more accurately assess HER-2/neu status and avoid inaccurate prognostication and inappropriate treatment.

Reproducibility of computer-quantified carotid plaque echogenicity: can we overcome the subjectivity?

BACKGROUND AND PURPOSE

We sought to assess the reproducibility, interobserver variability, and application to clinical studies of a new method for the quantitative assessment of carotid plaque echogenicity.

METHODS

Carotid plaques were scanned with the use of ultrasound, and their images were stored in a computer. They were normalized by assigning certain gray values to blood and adventitia, and the gray scale median (GSM) was used to quantify their echogenicity. The variability between storage media, between degrees of magnification, and between probes was assessed. The method was applied to 232 asymptomatic carotid plaques causing 60% to 99% stenosis in relation to the presence of ipsilateral CT-demonstrated brain infarcts. In all parts of the study the plaque GSM was measured before and after normalization to evaluate its effect. Interobserver agreement for the scanning process was assessed.

RESULTS

The GSM mean difference before and after normalization for variability studies of storage media, degrees of magnification, and probes was -14.5 and -0.12, 2.24 and 1.68, and -8.3 and -0.7, respectively. The median GSM of plaques associated with ipsilateral nonlacunar silent CT-demonstrated brain infarcts was 14, and that of plaques that were not so associated was 30 (P:=0.003). The interobserver GSM difference was -0.05 (95% CI, -1.7 to 1.6).

CONCLUSIONS

Our method decreases the variability between storage media and between probes but not the variability between degrees of magnification. It separates echomorphologically the carotid plaques associated with silent nonlacunar CT-demonstrated brain infarcts from plaques that are not so associated.

Comparison of PathVysion and INFORM fluorescence in situ hybridization kits for assessment of HER-2/neu status in breast carcinoma

BACKGROUND

Fluorescence in situ hybridization is advocated for precise assessment of HER-2/neu status in breast carcinoma; however, few objective data compare available kits for clinical laboratories contemplating development of the test.

METHODS AND RESULTS

Thirty breast carcinomas were analyzed for HER-2/neu amplification with the PathVysion kit (Vysis, Downers Grove, IL) and INFORM kit (Ventana Medical Systems, Tucson, AZ). Each kit was evaluated for morphology, background staining, technical and interpretation time, and cost. PathVysion detected amplification in seven of 30 cases (23.3%); INFORM detected six of 30 cases (20%). A greater percentage of PathVysion cases showed good morphology and lower background staining than INFORM. Technical and interpretation times, as well as cost, were less with PathVysion than INFORM.

CONCLUSION

PathVysion is superior to INFORM because it produces better morphology and less background staining and is faster and less expensive than the INFORM kit. It also includes a chromosome 17 probe that serves as an internal control and enables correction for chromosome 17 aneuploidy.

Alzheimer's disease due to an intronic presenilin-1 (PSEN1 intron 4) mutation: A clinicopathological study

We describe 21 affected individuals from a kindred with early-onset autosomal dominant familial Alzheimer's disease caused by an intronic presenilin-1 mutation (in intron 4). Mean age at onset of symptoms was 37.4 years [95% confidence interval (CI): 36.6-38.2 years], mean age at death was 44.7 years (95% CI: 43.1-46.3 years) and mean duration of illness was 7.3 years (95% CI: 5.9-8.7 years). Myoclonus and seizures were prominent features of this pedigree. In the four cases for whom neuropsychometric data were available, verbal memory impairment preceded visual memory deficits; naming was relatively preserved until late in the disease. One of these four cases underwent serial volumetric MRI scans demonstrating in vivo brain tissue loss of 3.9% (38.9 ml, annualized rate of atrophy: 1. 7%) over 22 months of follow-up. The four individuals who had necropsies demonstrated the neuropathological hallmarks of Alzheimer's disease. Apolipoprotein E (APOE) status was assessed in five individuals: the case with the youngest age at onset at 33 years of age was found to be homozygous epsilon4/epsilon4, > 1 SD below the mean age of onset for those of known APOE genotype (36.4 +/- 2.3 years, mean +/- SD), and > 2 SDs below the mean age of onset for the pedigree as a whole (37.4 +/- 1.7 years, mean +/- SD). APOE genotype may therefore modulate age at onset in this pedigree.

Generalised cerebral atrophy following temporal lobectomy for intractable epilepsy associated with mesial temporal sclerosis

Studies of post-operative imaging data have mainly concentrated on brain atrophy following radiotherapy and/or chemotherapy. We have investigated the effect of conventional surgery on the unresected brain tissue based on the comparison of magnetic resonance images acquired pre- and post-operatively in 13 subjects with a history of mesio-temporal epilepsy. The pre- and post-operative scans were co-registered prior to volumetric analysis. The total brain volume (TBV) was calculated by semi-automated segmentation, and the total volume loss was the difference between the post-operative and pre-operative TBV. The total volume of resection was determined by manual delineation in the post-operative scan. The atrophy volume in the post-operative scan was calculated as the difference between the total volume loss and the resection volume. In 6 cases, there was generalised cerebral atrophy of the order 4-5% of the total brain volume. In addition to the automated volumetric technique, the images were assessed by two expert neuroradiologists. There was complete correspondence between their assessment and the automated technique. The causes and significance of this phenomenon are unknown but it requires further investigation as it may be related to seizure control and neuropsychological changes following epilepsy surgery.

Electrostatic interactions affecting the active site of class sigma glutathione S-transferase

We have shown previously that the solvent-induced equilibrium unfolding mechanism of class Sigma glutathione S-transferase (GST) is strongly affected by ionic strength [Stevens, Hornby, Armstrong and Dirr (1998) Biochemistry 37, 15534-15541]. The protein is dimeric and has a hydrophilic subunit interface. Here we show that ionic strength alone has significant effects on the conformation of the protein, in particular at the active site. With the use of NaCl at up to 2 M under equilibrium conditions, the protein lost 60% of its catalytic activity and the single tryptophan residue per subunit became partly exposed. The effect was independent of protein concentration, eliminating the dissociation of the dimer as a possibility for the conformational changes. This was confirmed by size-exclusion HPLC. There was no significant change in the secondary structure of the protein according to far-UV CD data. Manual-mixing and stopped-flow kinetics experiments showed a slow single-exponential salt-induced change in protein fluorescence. For equilibrium and kinetics experiments, the addition of an active-site ligand (S-hexylglutathione) completely protected the protein from the ionic-strength-induced conformational changes. This suggests that the change occurs at or near the active site. Possible structural reasons for these novel effects are proposed, such as the flexibility of the alpha-helix 2 region as well as the hydrophilic subunit interface, highlighting the importance of electrostatic interactions in maintaining the structure of the active site of this GST.

Bilateral periventricular and subcortical heterotopia in a man with refractory epilepsy

PURPOSE

To report a novel malformation in a male subject with refractory partial seizures.

METHODS

Magnetic resonance imaging (MRI) and data reformatting in a subject referred for management of partial seizures.

RESULTS

The patient had four distinct partial seizure types, without learning disability. MRI demonstrated the novel association of bilateral laminar subcortical heterotopia, bilateral temporal periventricular heterotopia, and hippocampal malformation.

CONCLUSIONS

This previously unreported complex bilateral neocortical and archicortical malformation in a male patient cannot be explained by known genetic causes of heterotopia, raising the possibility of a novel gene involved in brain formation.

High yield criteria for emergency cranial computed tomography in adult patients with no history of head injury

OBJECTIVES

A recent American study identified clinical factors which effectively predicted those patients who would have significant findings on cranial computed tomography. It was proposed to apply these criteria in a UK setting and to determine whether modifications could be made to improve their efficiency.

METHODS

A prospective observational study was conducted over a four month period including all non-trauma adult patients referred from the accident and emergency (A&E) department for urgent cranial computed tomography. Presenting symptoms and signs were analysed for ability to predict clinically significant computed tomography findings, namely: acute infarct, malignancy, acute hydrocephalus, intracranial haemorrhage, or intracranial infection.

RESULTS

Sixty two patients were included; 22 (35%) had significant findings on computed tomography. Applying the original criteria (any of: age 60 years or older, focal neurology, headache with nausea or vomiting, altered mental status) to the study population showed that no clinically significant tomograms would have been omitted but only 11% fewer performed. Modifying the criteria by removing "age 60 years or older" and replacing "altered mental status" with a Glasgow coma score <14, still ensured 100% sensitivity and would have resulted in 19% fewer scans being performed.

CONCLUSION

Simple clinical criteria can be usefully applied to patients presenting to an A&E department in this country to target patients most likely to have clinically significant findings on urgent cranial computed tomography.