An investigation of WNT pathway activation and association with survival in central nervous system primitive neuroectodermal tumours (CNS PNET)

Central nervous system primitive neuroectodermal tumours (CNS PNET) are high-grade, predominantly paediatric, brain tumours. Previously they have been grouped with medulloblastomas owing to their histological similarities. The WNT/β-catenin pathway has been implicated in many tumour types, including medulloblastoma. On pathway activation β-catenin (CTNNB1) translocates to the nucleus, where it induces transcription of target genes. It is commonly upregulated in tumours by mutations in the key pathway components APC and CTNNB1. WNT/β-catenin pathway status was investigated by immunohistochemical analysis of CTNNB1 and the pathway target cyclin D1 (CCND1) in 49 CNS PNETs and 46 medulloblastomas. The mutational status of APC and CTNNB1 (β-catenin) was investigated in 33 CNS PNETs and 22 medulloblastomas. CTNNB1 nuclear localisation was seen in 36% of CNS PNETs and 27% of medulloblastomas. A significant correlation was found between CTNNB1 nuclear localisation and CCND1 levels. Mutations in CTNNB1 were identified in 4% of CNS PNETs and 20% of medulloblastomas. No mutations were identified in APC. A potential link between the level of nuclear staining and a better prognosis was identified in the CNS PNETs, suggesting that the extent of pathway activation is linked to outcome. The results suggest that the WNT/β-catenin pathway plays an important role in the pathogenesis of CNS PNETs. However, activation is not caused by mutations in CTNNB1 or APC in the majority of CNS PNET cases.

Regional variations in the extent and pattern of grey matter demyelination in multiple sclerosis: a comparison between the cerebral cortex, cerebellar cortex, deep grey matter nuclei and the spinal cord

BACKGROUND

Substantial grey matter (GM) demyelination occurs in both the cerebral cortex and spinal cord in multiple sclerosis (MS). GM demyelination also occurs in the cerebellar cortex and the deep GM nuclei of the brain. However, no study has made a direct "within subject" comparison of the extent of GM pathology between these regions.

AIM

To examine the extent and pattern of GM demyelination in the motor cortex, cingulate gyrus, cerebellum, thalamus and spinal cord in MS.

METHODS

Postmortem study using material from 14 MS cases and three controls. Sections were taken from the five predetermined areas and stained for proteolipid protein. The extent of GM and white matter (WM) demyelination was assessed in each region.

RESULTS AND CONCLUSION

Overall, 28.8% of the GM was demyelinated compared with 15.6% of the WM (p<0.001), with demyelination being greater in the GM than in the WM at each of the anatomical sites. There was substantial variation in the extent of demyelination between the different CNS regions. GM demyelination was most extensive in the spinal cord and cerebellum while WM demyelination was most prominent in the spinal cord.

Rheumatoid arthritis: a novel radiographic projection for hand assessment

Rheumatoid arthritis (RA) is the most common form of inflammatory disease, affecting 1-2% of the population. Posteroanterior (PA) and Brewerton projections are well established in radiographic practice for scoring and monitoring RA, but there is little evidence to demonstrate the diagnostic efficacy of these techniques. This work, by varying the positioning of a cadaveric hand, investigates whether an alternative radiographic projection could yield greater diagnostic information than the traditional techniques. Phase I of the study evaluated moving the hand 15 degrees from the anteroposterior position and then in 5 degrees increments in four directions: medial rotation, lateral rotation, flexion of the wrist and extension of the wrist. Phase II of the study took the optimum projections from Phase I and further manipulated these positions in a direction at right angles to the original position. Images were scored based on joint space visualisation in 29 joints. Results demonstrated that significantly higher diagnostic efficacy was evident with 15 degrees lateral rotation of the hand or 15 degrees flexion at the wrist compared to the Brewerton projection. Either projection is recommended, but on the basis of patient comfort, the latter of these novel positions, now known as the UCD projection, was chosen as the optimum procedure to replace the Brewerton projection. The value of using cadavers for the establishment of optimum radiographic procedures is highlighted.

Flexible eating and flexible insulin dosing in patients with diabetes: Results of an intensive self-management course

AIMS

To evaluate the outcomes of an established programme to teach patients to match their insulin dose to their carbohydrate intake.

RESEARCH DESIGN AND METHODS

A prospective observational study in Australia (Newcastle, NSW) of 137 consecutive patients with type 1 (n=82) or type 2 diabetes (n=55) over two successive years. Four educational principles were used to teach intensive insulin management and diabetes self-care skills including: carbohydrate counting and insulin dose adjustment, exercise, appropriate treatment of hypoglycaemia and hyperglycaemia, managing sickness, problem solving, communication with health professionals, goal setting, and the importance of support. Outcomes included changes at 4 and 12 months in HbA1c, self-efficacy measured by a diabetes empowerment scale (DES), diabetes specific quality of life (ADDQoL), and problem solving. Both intention to treat and efficacy analyses were performed.

RESULTS

Diabetes-related quality of life and diabetes problem solving skills improved significantly. Excluding 16 people who failed to adopt intensive insulin management and 24 who started with an HbA1c less than 7%, intention to treat analysis showed the average HbA1c fell from 8.7% initially to 8.1% at 12 months and the number of people with an HbA1c of less than 8% rose from 67 (48.9%) before the program to 86 (62.8%) afterwards.

CONCLUSIONS

An intensive diabetes self-management program led to improvements in HbA1c, empowerment, and quality of life that were largely sustained at 1 year. This is all the more remarkable given that the intervention was once only, entailed no long-term follow-up, and took place in normal clinical operations.

The Met Office Hadley Centre climate modelling capability: the competing requirements for improved resolution, complexity and dealing with uncertainty

Predictions of future climate change require complex computer models of the climate system to represent the full range of processes and interactions that influence climate. The Met Office Hadley Centre uses 'families' of models as part of the Met Office Unified Model Framework to address different classes of problems. The HadGEM family is a suite of state-of-the-art global environment models that are used to reduce uncertainty and represent and predict complex feedbacks. The HadCM3 family is a suite of well established but cheaper models that are used for multiple simulations, for example, to quantify uncertainty or to test the impact of multiple emissions scenarios.

Decreased substance P and NK1 receptor immunoreactivity and function in the spinal cord dorsal horn of morphine-treated neonatal rats

Opiate analgesic tolerance is defined as a need for higher doses of opiates to maintain pain relief after prolonged opiate exposure. Though changes in the opioid receptor undoubtedly occur during conditions of opiate tolerance, there is increasing evidence that opiate analgesic tolerance is also caused by pronociceptive adaptations in the spinal cord. We have previously observed increased glutamate release in the spinal cord dorsal horn of neonatal rats made tolerant to the opiate morphine. In this study, we investigate whether spinal substance P (SP) and its receptor, the neurokinin 1 (NK1) receptor, are also modulated by prolonged morphine exposure. Immunocytochemical studies show decreased SP- and NK1-immunoreactivity in the dorsal horn of morphine-treated rats, whereas SP mRNA in the dorsal root ganglia is not changed. Electrophysiological studies show that SP fails to activate the NK1 receptor in the morphine-treated rat. Taken together, the data indicate that chronic morphine treatment in the neonatal rat is characterized by a loss of SP effects on the NK1 receptor in lamina I of the neonatal spinal cord dorsal horn. The results are discussed in terms of compensatory spinal cord processes that may contribute to opiate analgesic tolerance.

PERSPECTIVE

This article describes anatomical and physiological changes that occur in the spinal cord dorsal horn of neonatal rats after chronic morphine treatment. These changes may represent an additional compensatory process of morphine tolerance and may represent an additional therapeutic target for the retention and restoration of pain relief with prolonged morphine treatment.

Evaluation of the topical hemostatic efficacy and safety of TISSEEL VH S/D fibrin sealant compared with currently licensed TISSEEL VH in patients undergoing cardiac surgery: a phase 3, randomized, double-blind clinical study

AIM

TISSEEL VH is the only commercially available fibrin sealant indicated as an adjunct to conventional methods of hemostasis during cardiac surgery. A next generation fibrin sealant (TISSEEL VH S/D) has been developed in frozen, ready-to-use form with an added virus inactivation step (solvent/detergent [S/D] treatment) to provide added safety and convenience to the currently licensed product. This study was performed to compare efficacy and safety of the two products.

METHODS

Phase 3, prospective, randomized, double-blind, multicenter study to compare TISSEEL VH S/D to TISSEEL VH during cardiac surgery. The primary efficacy endpoint was the proportion of patients who achieved hemostasis at the primary treatment site within 5 min, and maintained hemostasis until surgical closure.

RESULTS

The proportion of patients who achieved hemostasis at the primary treatment site within 5 min, and maintained hemostasis until surgical closure was 88.2% for TISSEEL VH S/D and 89.6% for TISSEEL VH in the intent-to-treat population. The difference in proportions, TISSEEL VH S/D minus TISSEEL VH, was 1.4% with a standard error of 3.70%. The lower 97.5% confidence bound of this difference was 8.6%, which is above the predefined noninferiority margin of 15%. Therefore, TISSEEL VH S/D is at least as efficacious as TISSEEL VH. The safety profile of TISSEEL VH S/D was very similar to that of currently licensed TISSEEL VH as assessed by the safety endpoints.

CONCLUSION

TISSEEL VH S/D is safe and effective for use as an adjunct to hemostasis in patients undergoing cardiac surgery.

The absence of endogenous beta-endorphin selectively blocks phosphorylation and desensitization of mu opioid receptors following partial sciatic nerve ligation

Phosphorylation of specific sites in the second intracellular loop and in the C-terminal domain have previously been suggested to cause desensitization and internalization of the mu-opioid receptor (MOP-R). To assess sites of MOP-R phosphorylation in vivo, affinity-purified, phosphoselective antibodies were raised against either phosphothreonine-180 in the second intracellular loop (MOR-P1) or the C-terminal domain of MOP-R containing phosphothreonine-370 and phosphoserine-375 (MOR-P2). We found that MOR-P2-immunoreactivity (IR) was significantly increased within the striatum of wild-type C57BL/6 mice after injection of the agonist fentanyl. Pretreatment with the antagonist naloxone blocked the fentanyl-induced increase. Furthermore, mutant mice lacking MOP-R showed only non-specific nuclear MOR-P2-IR before or after fentanyl treatment, confirming the specificity of the MOR-P2 antibodies. To assess whether MOP-R phosphorylation occurs following endogenous opioid release, we induced chronic neuropathic pain by partial sciatic nerve ligation (pSNL), which caused a significant increase in MOR-P2-IR in the striatum. pSNL also induced signs of mu opioid receptor tolerance demonstrated by a rightward shift in the morphine dose response in the tail withdrawal assay and by a reduction in morphine conditioned place preference (CPP). Mutant mice selectively lacking all forms of the beta-endorphin peptides derived from the proopiomelanocortin (Pomc) gene did not show increased MOR-P2-IR, decreased morphine antinociception, or reduced morphine CPP following pSNL. In contrast gene deletion of either proenkephalin or prodynorphin opioids did not block the effects of pSNL. These results suggest that neuropathic pain caused by pSNL in wild-type mice activates the release of the endogenous opioid beta-endorphin, which subsequently induces MOP-R phosphorylation and opiate tolerance.

A novel, non-substrate-based series of glycine type 1 transporter inhibitors derived from high-throughput screening

The synthesis and structure-activity relationships (SAR) of a series of indane and tetralin inhibitors of the type 1 glycine transporter, derived from a high-throughput screening (HTS) hit, are described. Key modifications that reduced the 5HT1B receptor affinity of the HTS hit and the P450 2D6 inhibition of subsequent analogues are delineated. While these modifications led to potent and selective GlyT1 inhibitors, HERG affinity and human microsomal clearance remain an issue for this series of compounds.

Establishing a pathological diagnosis in degenerative dementias

While clinicopathological studies have confirmed that Alzheimer's disease (AD) is the most common neurodegenerative cause of dementia, these same studies have also revealed that other degenerative pathologies account for a significant proportion of patients with cognitive decline. Because pathological assessment of non-Alzheimer neurodegenerative diseases now demands routine use of a costly panel of immunohistochemical techniques a scheme for staged examination of brain tissue has been developed. This scheme is weighted to initially screen out cases of Alzheimer's disease, dementia with Lewy bodies and vascular dementia using conventional staining methods and established diagnostic protocols, bringing in immunochemical techniques to discriminate between non-Alzheimer degenerative dementias. Diagnosis of pathologies causing the clinical syndrome of frontotemporal dementia can be ascertained using conventional staining supplemented by immunochemical detection of ubiquitin, tau protein and alpha beta crystallin. The diagnosis of prion disease is reliably confirmed by immunohistochemical detection of prion protein. This morphological assessment complements emerging genetic insights into many of these neurodegenerative diseases.

Impact of a national external quality assessment scheme for breast pathology in the UK

BACKGROUND

This article presents the results and observed effects of the UK National Health Service Breast Screening Programme (NHSBSP) external quality assurance scheme in breast histopathology.

AIMS/METHODS

The major objectives were to monitor and improve the consistency of diagnoses made by pathologists and the quality of prognostic information in pathology reports. The scheme is based on a twice yearly circulation of 12 cases to over 600 registered participants. The level of agreement was generally measured using kappa statistics.

RESULTS

Four main situations were encountered with respect to diagnostic consistency, namely: (1) where consistency is naturally very high-this included diagnosing in situ and invasive carcinomas (and certain distinctive subtypes) and uncomplicated benign lesions; (2) where the level of consistency was low but could be improved by making guidelines more detailed and explicit-this included histological grading; (3) where consistency could be improved but only by changing the system of classification-this included classification of ductal carcinoma in situ; and (4) where no improvement in consistency could be achieved-this included diagnosing atypical hyperplasia and reporting vascular invasion. Size measurements were more consistent for invasive than in situ carcinomas. Even in cases where there is a high level of agreement on tumour size, a few widely outlying measurements were encountered, for which no explanation is readily forthcoming.

CONCLUSIONS

These results broadly confirm the robustness of the systems of breast disease diagnosis and classification adopted by the NHSBSP, and also identify areas where improvement or new approaches are required.

The NHS breast screening programme (pathology) EQA: experience in recent years relating to issues involved in individual performance appraisal

BACKGROUND

The original role of the National Health Service breast screening programme (pathology) external quality assessment (EQA) scheme was educational; it aimed to raise standards, reinforce use of common terminology, and assess the consistency of pathology reporting of breast disease in the UK.

AIMS/METHODS

To examine the performance (scores) of pathologists participating in the scheme in recent years. The scheme has evolved to help identify poor performers, reliant upon setting an acceptable cutpoint. Therefore, the effects of different cutpoint strategies were evaluated and implications discussed.

RESULTS/CONCLUSIONS

Pathologists who joined the scheme improved over time, particularly those who did less well initially. There was no obvious association between performance and the number of breast cancer cases reported each year. This is not unexpected because the EQA does not measure expertise, but was established to demonstrate a common level of performance (conformity to consensus) for routine cases, rather than the ability to diagnose unusual/difficult cases. A new method of establishing cutpoints using interquartile ranges is proposed. The findings also suggest that EQA can alter a pathologist's practice: those who leave the scheme (for whatever reason) have, on average, marginally lower scores. Consequently, with the cutpoint methodology currently used (which is common to several EQA schemes) there is the potential for the cutpoint to drift upwards. In future, individuals previously deemed competent could subsequently be erroneously labelled as poor performers. Due consideration should be given to this issue with future development of schemes.

Diagnosis and management of dementia with Lewy bodies: third report of the DLB Consortium

The dementia with Lewy bodies (DLB) Consortium has revised criteria for the clinical and pathologic diagnosis of DLB incorporating new information about the core clinical features and suggesting improved methods to assess them. REM sleep behavior disorder, severe neuroleptic sensitivity, and reduced striatal dopamine transporter activity on functional neuroimaging are given greater diagnostic weighting as features suggestive of a DLB diagnosis. The 1-year rule distinguishing between DLB and Parkinson disease with dementia may be difficult to apply in clinical settings and in such cases the term most appropriate to each individual patient should be used. Generic terms such as Lewy body (LB) disease are often helpful. The authors propose a new scheme for the pathologic assessment of LBs and Lewy neurites (LN) using alpha-synuclein immunohistochemistry and semiquantitative grading of lesion density, with the pattern of regional involvement being more important than total LB count. The new criteria take into account both Lewy-related and Alzheimer disease (AD)-type pathology to allocate a probability that these are associated with the clinical DLB syndrome. Finally, the authors suggest patient management guidelines including the need for accurate diagnosis, a target symptom approach, and use of appropriate outcome measures. There is limited evidence about specific interventions but available data suggest only a partial response of motor symptoms to levodopa: severe sensitivity to typical and atypical antipsychotics in approximately 50%, and improvements in attention, visual hallucinations, and sleep disorders with cholinesterase inhibitors.

Cerebral white matter hyperintense lesions are associated with unstable carotid plaques

OBJECTIVES

The aim of this study was to determine whether unstable carotid plaques, a known risk factor for cerebral emboli, are associated with cerebral white matter lesions.

METHODS

Seventy-one symptomatic patients undergoing magnetic resonance imaging prior to carotid endarterectomy for high grade carotid stenosis were included in this study. The number and volume of white matter hyperintense lesions (WMHL) on fluid attenuated inversion recovery brain scans were compared according to the morphology of carotid plaque based upon the American Heart Association (AHA) histological classification.

RESULTS

Of the 57 patients who had good quality brain scans and non-fragmented carotid plaques, 15 plaques were defined as stable (type V) and 42 as unstable (type VI). After adjustment for the major risk factors affecting WMHL, unstable carotid plaques were found to be associated with more WMHL in the ipsilateral cerebral hemisphere than stable plaques (transformed means 2.50+/-1.2 vs. 1.53+/-1.1, p=0.016), however, there was only a trend towards larger WMHL volumes (p=0.079).

CONCLUSIONS

The observed association between unstable carotid plaques and the number of white matter lesions suggest that thromboembolic plaque activity may contribute to the development of leukoaraiosis, in particular smaller individual lesions. Larger studies are warranted to confirm this finding and explore the potential clinical impact for selecting candidates for carotid endarterectomy.

Camptothecin sensitivity in Werner syndrome fibroblasts as assessed by the COMET technique

Werner syndrome (WS) is an inherited genetic disease in which individuals display the premature aging of a selected subset of tissues. The disorder results from the loss of function mutations in the wrn gene. Wrn codes for a member of the RecQ helicase family with a unique nuclease domain. There is significant evidence that the role of wrn is to assist in the repair and reinitiation of DNA replication forks that have stalled. Loss of the wrn helicase imposes a distinct set of phenotypes at the cellular level. These include premature replicative senescence (in a subset of cell types), chromosomal instability, a distinct mutator phenotype, and hypersensitivity to a limited number of DNA damaging agents. Unfortunately, most of these phenotypes are not suitable for the rapid assessment of loss of function of the wrn gene product. However, WS cells have been reported to show abnormal sensitivity to the drug camptothecin (an inhibitor of topoisomerase type I). A rapid assay for this sensitivity would be a useful marker of loss of wrn function. The COMET (single-cell gel electrophoresis) assay is a rapid, sensitive, versatile, and robust technique for the quantitative assessment of DNA damage in eukaryotic cells. Using this assay, we have found that a significantly increased level of strand breaks can be demonstrated in WS cells treated with camptothecin compared with normal controls.