Long-term benefits and adverse effects of intermittent versus daily glucocorticoids in boys with Duchenne muscular dystrophy

OBJECTIVE

To assess the current use of glucocorticoids (GCs) in Duchenne muscular dystrophy in the UK, and compare the benefits and the adverse events of daily versus intermittent prednisolone regimens.

DESIGN

A prospective longitudinal observational study across 17 neuromuscular centres in the UK of 360 boys aged 3-15 years with confirmed Duchenne muscular dystrophy who were treated with daily or intermittent (10 days on/10 days off) prednisolone for a mean duration of treatment of 4 years.

RESULTS

The median loss of ambulation was 12 years in intermittent and 14.5 years in daily treatment; the HR for intermittent treatment was 1.57 (95% CI 0.87 to 2.82). A fitted multilevel model comparing the intermittent and daily regiments for the NorthStar Ambulatory Assessment demonstrated a divergence after 7 years of age, with boys on an intermittent regimen declining faster (p<0.001). Moderate to severe side effects were more commonly reported and observed in the daily regimen, including Cushingoid features, adverse behavioural events and hypertension. Body mass index mean z score was higher in the daily regimen (1.99, 95% CI 1.79 to 2.19) than in the intermittent regimen (1.51, 95% CI 1.27 to 1.75). Height restriction was more severe in the daily regimen (mean z score -1.77, 95% CI -1.79 to -2.19) than in the intermittent regimen (mean z score -0.70, 95% CI -0.90 to -0.49).

CONCLUSIONS

Our study provides a framework for providing information to patients with Duchenne muscular dystrophy and their families when introducing GC therapy. The study also highlights the importance of collecting longitudinal natural history data on patients treated according to standardised protocols, and clearly identifies the benefits and the side-effect profile of two treatment regimens, which will help with informed choices and implementation of targeted surveillance.

Global gene expression profiling confirms the molecular fidelity of primary tumor-based orthotopic xenograft mouse models of medulloblastoma

We previously showed that primary tumor-based orthotopic xenograft mouse models of medulloblastoma replicated the histopathological phenotypes of patients' original tumors. Here, we performed global gene expression profiling of 11 patient-specific xenograft models to further determine whether the xenograft tumors were molecularly accurate during serial subtransplantations in mouse brains and whether they represented all the molecular subtypes of medulloblastoma that were recently described. Analysis of the transcriptomes of 9 pairs of matched passage I xenografts and patients' tumors revealed high correlation coefficients (r(2) > 0.95 in 5 models, > 0.9 in 3 models, and > 0.85 in 1 model) and only identified 69 genes in which expressions were altered (FDR = 0.0023). Subsequent pair-wise comparisons between passage I, III, and V xenografts from the 11 models further showed that no dramatic alterations were introduced (r(2) > 0.9 in 8 models and > 0.8 in 3 models). The genetic abnormalities of each model were then identified through comparison with control RNAs from 5 normal cerebella and 2 fetal brains. Hierarchical clustering using 3 previously published molecular signatures showed that our models span the whole spectrum of molecular subtypes, including SHH (n = 2), WNT (n = 2), and the most recently identified group C (n = 4) and group D (n = 3). In conclusion, we demonstrated that the 11 orthotopic medulloblastoma xenograft models were molecularly faithful to the primary tumors, and our comprehensive collection of molecularly distinct animal models should serve as a valuable resource for the development of new targeted therapies for medulloblastoma.

P1-11-07: Impact of Reduction in Cost-Sharing on Screening Mammography Utilization among Rural U.S. Women

Background: Early detection of breast cancer through mammography screening leads to earlier stage at diagnosis and improved survival. For reasons that are poorly understood, in recent years the rate of screening has demonstrated periods of decline, and screening has proved to be less common in rural compared to urban areas of the U.S. In 2006, the National Rural Electric Cooperative Association (NRECA) which provides health care to over 100,000 electrical workers and their families in primarily rural areas of the U.S. eliminated copayments for screening mammography in an effort to boost screening rates. We conducted a population based analysis of screening utilization to determine the impact of this policy initiative. Methods: Using the NRECA insurance database, all women aged 40 to 64 with no prior history of breast cancer or DCIS (based on ICD-9 codes) were identified and we evaluated claims data on annual screening mammography utilization (SMU) between 1999 and 2009 stratified by age group in 5 year intervals. Changes in SMU over time were assessed focusing on the periods before and after the policy change in January 2006. We also evaluated diagnosis of breast cancer and receipt of mastectomy and chemotherapy as a potential proxy for more advanced disease at diagnosis. Descriptive statistics were estimated and the mammography rate was fitted on years using the identity link (proc genmod in SAS). In order to test the impact of the 2006 change in cost-sharing on the trend in mammography rate, we introduced change point terms in slope and intercept to the linear model. Chi-squared test for 2×2 tables was used to compare SMU rates between two consecutive years for each age group. All p-values are two-sided.

Results: During this period, a mean of 20,825 women aged 40 to 64 each year received health insurance through NRECA. SMU increased from 38.1% in 1999 to 49.5% in 2009. Analyzing SMU before and after the change in cost sharing policy demonstrates a significant change in the rate of screening at the 2006 intercept (p = 0.0275) although the slope of year to year change in screening rate did not change. In stratified analysis there was a significant change in SMU between 2005 and 2006 for all age groups. In the 4 years prior to the NRECA change in policy, 554 women were diagnosed with breast cancer and 40 underwent mastectomy and chemotherapy. In comparison, from 2006 to 2009, only 20 women out of 540 with newly diagnosed breast cancer underwent such therapy (7.2% prior to policy change vs. 3.7% following, P = 0.01).

Conclusion: The impact of health plan benefits changes can be evaluated among a primarily rural population of women aged 40 to 64 using the novel NRECA database. Annual SMU remained low, but improved following elimination in copayments suggesting that financial barriers impact screening. Multiple factors may explain changes in SMU and treatment intensity over time. However, cost-sharing for high value health care services may have unintended negative consequences. Further evaluation of this database is planned to evaluate biannual screening rates, correlation with sociodemographic factors, impact of recent controversy over screening guidelines and additional barriers to screening utilization in this rural population.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-11-07.

Abstract 570: Radiation resistance of orthotopic glioblastoma xenografts is mediated by increasing CD133+ cell fraction, mobilizing G0 cells into G1 phase, and activating self-renewal and mesenchymal genes

Pediatric glioblastoma multiforme (pGBM) is a highly aggressive brain tumor with poor prognosis. Resistance to ionizing radiation, which is one of the major therapeutic regimes, is believed to play a critical role in tumor recurrence and ultimate treatment failure. However, little is known about the cellular and molecular mechanisms of radioresistance in pGBM, particularly the in vivo responses of tumor cells toward clinically relevant fractionated radiotherapy. To gain a better understanding of the radioresistance mechanisms, we administered fractionated radiation (2Gy per day × 5 times) to SCID mice bearing pre-established orthotopic xenograft tumors derived from two independent fresh patient tumors. Examination of the xenograft tumors immediately at the end of radiation treatment showed that the fractionated radiotherapy significantly increased the abundance of CD133+ tumor cells, and drove quiescent G0 phase cells (both CD133+ and CD133-) into G1 phase in both models. Immunohistochemical examination of key regulators of stem cell self-renewal revealed elevation of BMI-1 and SOX2 gene expression in vivo in the xenograft tumors. Additionally, we found that radiotherapy promoted mesenchymal transition, as the intensity and distribution of fibronectin, a mesenchymal marker, was remarkably enhanced. Further analysis of the recurrent xenograft tumors ∼ 5 weeks post-fractionated radiation showed that the increased CD133+ fraction, the elevated expressions of BMI-1 and SOX2 as well as fibronection were maintained. In conclusion, our data demonstrated, for the first time, that failure of radiotherapy is mediated by activated pathways related to self-renewal of cancer stem cells and mesenchymal transition. Since this study was conducted in vivo in clinically relevant animal models in a setting that is the closest to human brain tumors, our findings provided strong preclinical evidence to suggest that new stratigies are needed to inhibit these radiation triggered-pathways to improved therapeutic efficacy in pediatric GBM patient.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 570. doi:10.1158/1538-7445.AM2011-570

Abstract 4185: Isolation of cancer stem-like cells from a novel orthotopic xenograt model of supratentorial primitive neuroectodermal tumor that is susceptible to oncolytic Seneca Valley Virus

Purpose: Supratentorial primitive neuroectodermal tumor (PNET) accounts for 2-3% of all pediatric brain tumors. Despite multimodality therapies, the clinical outcome remains poor, and the 5-year progression free survival rate is less than 40%. Clinically relevant animal models are needed for understanding tumor biology and developing more effective therapies. Here we report our recent development of a clinically relevant animal model, isolation and characterization of cancer stem-like cells in the xenograft tumors, and preclinical investigation of the antitumor efficacy of a novel picorna oncolytic virus Seneca Valley Virus-001 (SVV-001) both in vitro and vivo, especially in cancer stem-like cells.

Experimental Design: Orthotopic xenograft mouse model was developed by direct injection of 105 tumor cells from a freshly resected brain PNET tumor specimen into the right cerebrum of Rag2/severe combined immunodeficient mice. CD133+ cells were quantitatively analyzed and isolated with FACS using human-specific antibodies against CD133. Antitumor activity of SVV-001was evaluated in vitro in cultured xenograft tumor cells and in vivo in mice bearing pre-formed xenograft tumors.

Results: A novel transplantable PNET xenograft model IC-2664PNT was established. The xenograft tumors not only replicate the biologic phenotypes but also preserve cancer stem-like cell pools. The IC-2664PNET neurospheres, which expressed high levels of CD133 and nestin, were efficiently infected and killed by SVV-001 (0.5-25 virus particle/ cell). A single tail vein injection of SVV-001 (5×1012 virus particle/kg) prolonged survival time of PNET xenograft model.

Conclusions: We have established the first clinically relevant animal model for childhood supratentorial PNET. It replicated the major histopathological features of the original patient tumor, and preserved a CD133+ stem cells pool during serial subtransplantations. SVV-001 has potent antitumor efficacy in PNET, especially selectively kill cancer stem-like cells, and prolong survival in vivo.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4185.

Abstract 4192: Global gene expression profiling confirms the molecular fidelity of primary tumor-based orthotopic xenograft mouse models of medulloblastoma

Clinically relevant animal models are needed for understanding biology and testing novel therapies in medulloblastoma (MB), the most common malignant brain tumor that occurs in children. We have recently established a panel of orthotopic xenograft mouse models of MB through direct injection of fresh surgical specimens into the cerebella of Rag2/SCID mice. The xenograft tumors were previously shown to have replicated key histopathological phenotypes and invasive growth characteristics of the original patient tumors. The objective of the current study is to complete the molecular characterization of 11 MB models that have been serially passaged in vivo in mouse brains for at least three generations. Whole genome gene expression profiling was performed in duplicate with Illumina HumanWG6 v3 gene expression profiling beadchip that contains more than 48,000 probes. Our results showed that the xenograft tumors are molecularly accurate. When the nine passage I xenograft tumors were compared with their original patient tumors, high correlation coefficiency were observed (r2 &gt;0.95 in five models, &gt;0.9 in three models, and &gt;0.85 in one model). Serial subtransplantation up to five times did not cause significant changes of gene expression pattern (r2&gt;0.9 in eight models, &gt;0.8 in three models). Using RNAs from 4 normal fetal brains, one child cerebellum, and 5 adult cerebella as control, we further showed that these xenograft models, although molecularly independent displaying distinct gene expression profiles, can be classified into five different subcategories. A selected set of the differentially expressed genes were validated using real-time RT-PCR and Immunohistochemistry. In conclusion, this study provided strong experimental evidence to demonstrate that primary tumor-based orthotopic xenograft mouse models of MBs are molecularly accurate, and our findings of genetic abnormalities should significantly facilitate the rationally designed preclinical drug screenings in the near future.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4192.

Direct orthotopic transplantation of fresh surgical specimen preserves CD133+ tumor cells in clinically relevant mouse models of medulloblastoma and glioma

Recent identification of cancer stem cells in medulloblastoma (MB) and high-grade glioma has stimulated an urgent need for animal models that will not only replicate the biology of these tumors, but also preserve their cancer stem cell pool. We hypothesize that direct injection of fresh surgical specimen of MB and high-grade glioma tissues into anatomically equivalent locations in immune-deficient mouse brains will facilitate the formation of clinically accurate xenograft tumors by allowing brain tumor stem cells, together with their non-stem tumor and stromal cells, to grow in a microenvironment that is the closest to human brains. Eight of the 14 MBs (57.1%) and two of the three high-grade gliomas (66.7%) in this study developed transplantable (up to 12 passages) xenografts in mouse cerebellum and cerebrum, respectively. These xenografts are patient specific, replicating the histopathologic, immunophenotypic, invasive/metastatic, and major genetic (analyzed with 10K single nucleotide polymorphism array) abnormalities of the original tumors. The xenograft tumor cells have also been successfully cryopreserved for long-term preservation of tumorigenicity, ensuring a sustained supply of the animal models. More importantly, the CD133(+) tumor cells, ranging from 0.2%-10.4%, were preserved in all the xenograft models following repeated orthotopic subtransplantations in vivo. The isolated CD133(+) tumor cells formed neurospheres and displayed multi-lineage differentiation capabilities in vitro. In summary, our study demonstrates that direct orthotopic transplantation of fresh primary tumor cells is a powerful approach in developing novel clinical relevant animal models that can reliably preserve CD133(+) tumor cell pools even during serial in vivo subtransplantations. Disclosure of potential conflicts of interest is found at the end of this article.

Pallidal stimulation for pantothenate kinase-associated neurodegeneration dystonia

Pantothenate kinase-associated neurodegeneration is associated with generalised dystonia and cognitive deterioration. Limited evidence suggests that pallidal deep brain stimulation improves physical functioning. This is a report of the assessment and treatment of a severely affected patient in whom pallidal deep brain stimulation improved both physical and psychosocial functioning. Implications for treatment are briefly discussed.

X-ray CT dose in normoxic polyacrylamide gel dosimetry

This study reports on the effects of x-ray CT dose in CT imaged normoxic polyacrylamide (nPAG) gel dosimeters. The investigation is partitioned into three sections. First, the CT dose absorbed in nPAG is quantified under a range of typical gel CT imaging protocols. It is found that the maximum absorbed CT dose occurs for volumetric imaging and is in the range of 4.6 +/- 0.2 cGy/image. This does scales linearly with image averaging. Second, using Raman spectroscopy, the response of nPAG to CT imaging photon energies (i.e., 120-140 kVp) is established and compared to the well known dose response of nPAG exposed to 6 MV photons. It is found that nPAG exhibits a weaker response (per unit dose) to 140-kVp incident photons as compared to 6 MV incident photons (slopes m6 mv = -0.0374 +/- 0.0006 Gy(-1) and m140 kVp = -0.016 +/- 0.001 Gy(-1)). Finally, using the above data, an induced change in CT number (deltaN(CT)) is calculated for nPAG imaged using a range of gel imaging protocols. It is found that under typical imaging protocols (120-140 kVp, 200 mAs, approximately 16-32 image averages) a deltaN(CT) < 0.2 H is induced in active nPAG dosimeters. This deltaN(CT) is below the current limit of detectability of CT nPAG polymer gel dosimetry. Under expanded imaging protocols (e.g., very high number of image averages) an induced deltaN(CT) of approximately 0.5 H is possible. In these situations the additional polymerization occurring in nPAG due to the imaging process may need to be accounted for.

Surgery for scoliosis in Duchenne muscular dystrophy

BACKGROUND

Scoliosis in people with Duchenne muscular dystrophy is usually progressive and treated with surgery. However, it is unclear whether the existing evidence is sufficiently scientifically rigorous to support a recommendation for spinal surgery for most people with Duchenne muscular dystrophy and scoliosis.

OBJECTIVES

The objectives of this systematic review were to determine the effectiveness and safety of spinal surgery in Duchenne muscular dystrophy patients with scoliosis. We intended to test whether spinal surgery is effective in increasing life expectancy, improving respiratory function, improving quality of life and overall functioning; and whether spinal surgery is associated with severe adverse effects.

SEARCH STRATEGY

We searched the specialized registers of the Cochrane Neuromuscular Disease Group and Cochrane Back Group, the Cochrane Central Register of Controlled Trials (January 2006), MEDLINE (January 1966 to January 2006), EMBASE (January 1980 to January 2006), Dissertation Abstracts International (1861 to Jan 2006), CINAHL (January 1982 to January 2006), and the National Institute of Health Clinical Trials Database (January 2006). No language restrictions were imposed.

SELECTION CRITERIA

Controlled clinical trials using random or quasi-random allocation of treatment evaluating all forms of spinal surgery for scoliosis in patients with Duchenne muscular dystrophy were to be included in the review. The control interventions would have been no treatment, non-operative treatment, or a different form of spinal surgery.

DATA COLLECTION AND ANALYSIS

Two authors examined the search results and evaluated the study characteristics against inclusion criteria to decide which ones would be included in the review.

MAIN RESULTS

A total of 402 studies were identified from electronic searching. Thirty-six studies were relevant but none met the inclusion criteria for the review, because they were not clinical trials but prospective or retrospective reviews of case series.

AUTHORS' CONCLUSIONS

Since there were no randomized controlled clinical trials available to evaluate the effectiveness of scoliosis surgery in people with Duchenne muscular dystrophy, no evidence-based recommendation can be made for clinical practice. Patients should be informed about the uncertainty of benefits and potential risks of surgery for scoliosis. Randomized controlled trials are needed to investigate the effectiveness of scoliosis surgery, in terms of patients' quality of life, functional status, respiratory function and life expectancy.

Investigation of tetrakis hydroxymethyl phosphonium chloride as an antioxidant for use in x-ray computed tomography polyacrylamide gel dosimetry

Of the antioxidants used to scavenge oxygen in polymer gel dosimeters, tetrakis (hydroxymethyl) phosphonium chloride (THPC) has been shown to hold great promise due to its rapid oxygen scavenging abilities. In this study we (a) investigate the use of THPC as an antioxidant for polyacrylamide gel (PAGAT) dosimeters used in conjunction with x-ray computed tomography (CT) and (b) work to establish the reaction mechanisms of THPC with the polymer gel constituents. We establish the dose response reproducibility of PAGAT dosimeters when imaged with CT and show that PAGAT dosimeters exhibit highly reproducible dose responses for a range of irradiation times post gel manufacture (2-6 h) and CT imaging times post gel irradiation (1-5 days). The THPC concentration within the gel leading to a maximized dose response and minimized O(2) inhibition of polymerization is found to be approximately 4.5 mM. We further assess the stability of PAGAT dosimeters by investigating the reactions of THPC with the individual gel constituents. The importance of utilizing deionized water in polymer gel manufacture is noted. We show that, while THPC remains unreactive with acrylamide and bis-acrylamide under unirradiated conditions, THPC can react with gelatin to increase the cross-linking of the gelatin matrix in unirradiated dosimeters. THPC reactions with gelatin can lead to the lower observed dose sensitivity of PAGAT (approximately 0.36 +/- 0.04 H Gy(-1)) as compared to polyacrylamide gels manufactured under anoxic conditions (approximately 0.83 +/- 0.03 H Gy(-1)). The reactions of THPC which lead to O(2) scavenging, and potential reactions of THPC with other gel constituents, are proposed.

Stress in UK intensive care unit doctors

BACKGROUND

Doctors have long been considered at risk of occupational stress.

METHODS

A postal survey of all members of the Intensive Care Society using validated instruments.

RESULTS

Eight-five per cent of members returned questionnaires and 70% were eligible for the study. Twenty-nine per cent were suffering General Health Questionnaire-12 (GHQ-12) identified distress and 12% Symptom Checklist-Depression (SCL-D) defined depression. There were no significant age or sex differences between staff suffering distress or depression and those who did not. Dissatisfaction with career correlated highly with both distress and depression (P<0.01). Twenty doctors (3%) were bothered by suicidal thoughts. The most stressful aspects of work were bed allocation, being over-stretched, effect of hours of work and stress on personal/family life, and compromising standards when resources are short. Logistic regression revealed mental health problems were predicted by five stressors: 'lack of recognition of one's own contribution by others'; 'too much responsibility at times'; 'effect of stress on personal/family life'; 'keeping up to date with knowledge'; and 'making the right decision alone'.

CONCLUSIONS

Nearly one in three ICU doctors appeared distressed (GHQ), and one in 10 depressed (SCL-D); this is no greater than that reported in other specialities. Perceived stressors reveal some key areas of concern for the employer and the specialty.

Tethering of the vertebral artery in the congenital arcuate foramen of the atlas vertebra: a possible cause of vertebral artery dissection in children

Twelve children with vertebrobasilar artery stroke are reported (seven males, five females; aged 6 months to 15 years). Patient 1 showed an arcuate foramen in the posterior arch of the atlas, an anatomical variant occurring in 3 to 15% of the population. It was hypothesized that the presence of the arcuate foramen might cause tethering of the vertebral artery and lead to its dissection by repetitive trauma. Lateral plain films of the cervical spine in cases of posterior circulation stroke were taken. Eight of 11 patients showed aberrant arcuate foramina. Of the remaining three patients, one had normal cervical spine X-rays, one had an absent right posterior arch of the atlas following previous surgery for a cervical meningocele, and one patient had incomplete ossification of the vertebrae. Seven of the nine patients with arcuate foramina had vertebral angiograms. In all cases this showed the vertebral artery passing through the arcuate foramen before entering the brain and an appearance consistent with arterial dissection and occlusion at the same site below the foramen. Most documented cases of posterior circulation stroke in children follow trauma, which may be minimal or repetitive, with thrombotic occlusion of the artery at C1-C2 level. The association with an arcuate foramen and its possible causative role in the genesis of posterior circulation stroke in children has not been previously recognized. There may be a causal association between the presence of an arcuate foramen, tethering of the vertebral artery in the foramen, and dissection from repetitive trauma with movement of the neck.

Routine intracranial pressure monitoring in acute coma

BACKGROUND

Studies in traumatic encephalopathy first led to the insight that the damage seen was not just due to direct consequences of the primary injury. A significant, and potentially preventable, contribution to the overall morbidity arose from secondary hypoxic-ischaemic damage. Brain swelling accompanied by raised intracranial pressure (ICP) resulted in inadequate cerebral perfusion with well-oxygenated blood. Detection of raised ICP could be useful in alerting clinicians to the need to improve cerebral perfusion, with consequent reductions in brain injury.

OBJECTIVES

To determine whether routine ICP monitoring in all acute cases of severe coma reduces the risk of all-cause mortality or severe disability at final follow up.

SEARCH STRATEGY

We searched MEDLINE, EMBASE, The Injuries Group's specialised register and the reference lists of all relevant articles and review articles. In addition we searched the Index of Scientific and Technical Proceedings using "intracranial pressure" as keyword.

SELECTION CRITERIA

All randomised controlled studies of real-time ICP monitoring by invasive or semi-invasive means in acute coma (traumatic or non-traumatic aetiology) versus no ICP monitoring (ie clinical assessment of ICP ) DATA COLLECTION AND ANALYSIS: Primary outcome measures were all-cause mortality and severe disability at the end of the follow up period.

MAIN RESULTS

No studies meeting the selection criteria have been identified to date.

REVIEWER'S CONCLUSIONS

There are no data from randomised controlled trials that can clarify the role of ICP monitoring in acute coma.

Familial thrombophilia associated with fibrinogen paris V: Dusart syndrome

We report on a family with a history of venous thromboembolism associated with fibrinogen Paris V (fibrinogen Aalpha-Arg554-->Cys). Ten members experienced thrombotic events, including 4 with fatal pulmonary emboli. Pulmonary embolism was the presenting feature in 4. Those with the mutation and a history of thrombosis had somewhat higher fibrinogen concentrations than those with the mutation and no thrombosis (294 +/- 70 mg/dL vs 217 +/- 37 mg/dL, respectively). The Paris V mutation consistently caused a prolongation of the reptilase time, and fibrin clots containing the abnormal fibrinogen were more translucent than normal clots. Given the early onset of symptoms and the initial presentation with pulmonary embolism in some family members, it was justifiable to offer prophylactic anticoagulation with warfarin to carriers of the mutation. Fibrinogen Paris V has now been reported in 4 apparently unrelated families, indicating that it is a relatively common cause of dysfibrinogenemia-associated thrombosis.

Detection of damage to the mitochondrial genome in the oncocytic cells of Warthin's tumour

Warthin's tumour of the salivary glands is composed of oncocytic cells containing excessive numbers of mitochondria which show frequent structural abnormalities and reduced metabolic function. Recent evidence of a strong association between cigarette smoking and the occurrence of Warthin's tumour prompted this study, to look for evidence of damage to mitochondrial DNA (mtDNA) that could be the result of an increase in oxidative stress; two-colour fluorescence in situ hybridization (FISH) was developed to show the distribution of mitochondria with deleted mtDNA in paraffin wax-embedded material. Approximately 10% of mtDNA bears the 'common' 4977 bp deletion. Using the polymerase chain reaction (PCR), the 4977 bp deletion was further quantified, in Warthin's tumour and age-matched normal parotid control tissue. Whilst the deletion was present in all parotid tissue, its presence was significantly higher in oncocytic tumour cells. In a small number of controls, there was a trend towards higher concentrations of the deletion in smokers.

Epidemiology of pyridoxine dependent and pyridoxine responsive seizures in the UK

OBJECTIVE

To study the epidemiology of pyridoxine dependent seizures and other forms of pyridoxine responsive seizures.

DESIGN

Monthly notifications to the British Paediatric Surveillance Unit over two years. Questionnaire follow up.

SETTING

UK and the Republic of Ireland.

PATIENTS

Children aged 15 years or younger whose seizures respond to pyridoxine.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Numbers of children with definite, probable, and possible pyridoxine dependent seizures or other seizures responsive to pyridoxine.

RESULTS

Point prevalence and birth incidence: 1/687 000 and 1/783 000, respectively (definite and probable cases); 1/317 000 and 1/157 000, respectively (all types of pyridoxine responsiveness). NOTIFICATIONS: Pyridoxine dependency: 14 definite, 9 probable, and 10 possible cases; neonatal seizures not meeting case definitions: 7; infantile spasms: 5. Eight of 18 families of definite/probable cases had 2 affected siblings. Just over a third had atypical presentations and just under a third had features and/or initial diagnoses of birth asphyxia and neonatal hypoxic ischaemic encephalopathy.

CONCLUSIONS

Pyridoxine dependency is rare. Atypical presentations are relatively frequent. A trial of pyridoxine is justified in all cases of early onset intractable seizures or status epilepticus, whatever the suspected cause.

An assessment of the sensitivity of the Cedars-Sinai quantitative gated SPECT software to changes in the reconstruction of the short-axis slices

OBJECTIVE

This study assessed whether variations in count density, reconstruction filtering parameters and the short-axis orientation selected for reconstructions of myocardial short-axis slices significantly influenced the left ventricular ejection fraction (LVEF) calculated from a gated myocardial perfusion SPECT study.

METHODS

The Cedars-Sinai quantitative gated SPECT software package was used to estimate the LVEF from gated 99mTc-sestamibi and 201TI gated SPECT studies in 20 patients. Oblique slices were reconstructed 12 times for each study, independently varying the filter cutoff and the orientation of the short axis each time.

RESULTS

There were no clinically significant changes in the LVEF over the range of cutoff frequencies or orientation for either the 201TI or 99mTc-sestamibi studies. There was excellent agreement between the LVEF calculated from the 201TI and 99mTc-sestamibi studies on the same patients using the default filter (mean difference = 0.25% points).

CONCLUSIONS

The Cedars-Sinai quantitative gated SPECT software package for parallel-hole collimators can be used with confidence to obtain an LVEF, and is not sensitive to variations in count density, filtering parameters or short-axis orientation.

The designated forensic professional program: a state government-university partnership to improve forensic mental health services

As the law/mental health field has expanded and matured in the last 20 years, the sophistication required by mental health professionals in order to respond appropriately to legal questions has grown significantly. Courts and legislatures define a growing number of legal competencies. Judges and attorneys are more familiar with mental health law than they were 10 or 20 years ago.

Congenital paraplegia following maternal hypotension

Congenital paraplegia, with partial improvement over the first months of life, occurred in a female neonate born at 35 weeks' gestation, whose mother had suffered hypotension and hypoxaemia due to anaphylaxis 12 weeks earlier. Our patient subsequently had an acute encephalopathy during a respiratory illness with later developmental delay. We speculate that the baby's paraplegia resulted from spinal-cord ischaemia in utero. The aim of this report is to describe the spinal presentation.

The laryngeal mask airway in experimental pig anaesthesia

The pig is used as a large animal model in many research projects. Standard practice for airway maintenance under general anaesthesia is using endotracheal (ET) intubation after intravenous induction to a near surgical plane. This is a technically demanding skill, requiring the assistance of an experienced technician. A technique is required which simplifies pig anaesthesia. This study examined the feasibility and potential advantages of using the laryngeal mask airway (LMA) in 10 pigs during laparotomy under spontaneous breathing anaesthesia. The results show that the LMA can be inserted rapidly, with minimal time for airway control by researchers relatively inexperienced in anaesthesia and is associated with few complications. By removing the need for intravenous induction, an entire step in the anaesthetic process is removed. The LMA designed for humans fits well in the pig hypopharynx; all pigs could be manually ventilated with no detectable gas leak. Although the pigs in this study were spontaneously breathing it is proposed that the LMA should be further investigated in studies of artificially ventilated pigs.

Experimental study of electrolysis-induced hepatic necrosis

BACKGROUND

One of the most promising but unexplored methods for treating patients with irresectable liver tumours is electrolysis. This study examined the effect of increasing 'current dose' on the volume of the lesion induced in normal rat liver.

METHODS

A direct current generator, connected to platinum electrodes implanted in the rat liver, was used to examine the effect of (1) varying current doses from 1 to 5 coulombs and (2) electrode separation (2 or 20 mm), on the volume of liver necrosis.

RESULTS

There was a significant correlation (P < 0.001) between the current dose and the volume of necrosis produced for each electrode separation. Placing the electrodes 2 mm apart resulted in smaller total volumes of necrosis than placing them 20 mm apart when anode lesions were significantly larger than cathode lesions (P< 0.05). Liver enzymes (aspartate aminotransferase, alanine aminotransferase) were significantly raised 1 day after treatment (P < 0.001) and predicted the total volume of hepatic necrosis (P < 0.001).

CONCLUSION

Predictable and reproducible areas of liver necrosis are produced with electrolysis. If these results extrapolate to larger animal models, this technique has potential for patients with irresectable primary and secondary liver tumours.

Benign familial neonatal convulsions: abnormal intrauterine movements, provocation by feeding and ICTAL EEG

An infant with benign familial neonatal convulsions had abnormal movements during the last 2 months of pregnancy suggestive of intrauterine seizures. His postnatal seizures, one of which was captured by electroencephalography, had both partial and generalized features. Most seizures appeared to be provoked by feeding.

Utrophin abundance is reduced at neuromuscular junctions of patients with both inherited and acquired acetylcholine receptor deficiencies

Congenital myasthenic syndromes are a heterogeneous group of conditions in which muscle weakness resulting from impaired neuromuscular transmission is often present from infancy. One form of congenital myasthenic syndrome is due to a reduction of the number of acetylcholine receptors (AChRs) at the neuromuscular junction. We describe four new cases of AChR deficiency, characterized by a reduction in both miniature endplate potential amplitude and AChR abundance accompanied by elongation of the neuromuscular junction and some decrease in postsynaptic folding. A number of cytoplasmic proteins are normally associated with the postsynaptic membrane and may contribute to the clustering of AChRs at the neuromuscular junction. We therefore investigated the expression of several of these proteins in these AChR-deficiency patients. In each patient, immunolabelling of the neuromuscular junction for rapsyn, dystrophin, beta-dystroglycan and a form of beta-spectrin was strong but that for utrophin was markedly reduced or absent. This suggested that a defect in utrophin expression might underlie the congenital AChR deficiency. However, a reduction in utrophin labelling was also seen in three patients with adult acquired autoimmune myasthenia gravis in whom AChR loss results directly from the extracellular binding of autoantibodies. We conclude that the loss of AChRs in AChR deficiency does not result from the absence of rapsyn or beta-dystroglycan and that reduction of utrophin is probably secondary to the loss of AChRs. The possible role of AChRs and/or utrophin in determining the extent of postsynaptic folding is discussed.

Pyridoxine-dependent seizures: demographic, clinical, MRI and psychometric features, and effect of dose on intelligence quotient

A regional population-based survey identified six patients with pyridoxine dependency. Four presented on the first day of life and the other two at 1 and 8 months of age. Apart from multiple seizure types, other presenting features included jitteriness; encephalopathy, at first thought to be hypoxic-ischaemic; hepatomegaly, and abdominal distension with bilious vomiting. Later problems included break-through fits with fever; transient visual agnosia; squint; severe articulatory apraxia; motor delay with later dyspraxia; macrocephaly, and post-haemorrhagic hydrocephalus. Magnetic resonance imaging showed variable structural abnormalities in all the early onset cases. Psychometric assessment revealed a stereotyped pattern of intelligence scale subtest scores, with a specific impairment of expressive verbal ability. In a prospective open study over one year, an increased dose of pyridoxine was associated with an improvement in IQ, particularly in performance subtests. Pyridoxine dependency is more common than has been thought. It has a wider range of clinical features than the classical neonatal seizures and causes specific impairments of higher function, some of which may be reversible. The dosage of pyridoxine should be optimal for IQ as well as seizure control.

Self-paced learning stations for tuberculosis respirator training: report of a pilot program

BACKGROUND

In response to the Centers for Disease Control and Prevention's recently issued "Guidelines for Preventing the Transmission of Mycobacterium Tuberculosis in Health-Care Facilities, 1994," during May 1994 we implemented and evaluated a pilot tuberculosis respirator training program that used four self-directed learning stations, through which participants proceeded at their own pace. Employee tuberculin skin testing was included in the training program.

METHODS

The time required to train each employee was recorded. At the completion of the training program, all participants were asked to assess their ability to attain the learning objectives and whether they believed the program format was an effective and efficient use of their time. Two weeks later, a convenience sample of 100 employees completed an 11-question test designed to measure knowledge retention.

RESULTS

One hundred seventy-six employees completed training during the pilot period. The average time necessary to train each employee was 19.5 minutes. Overall 97.1% of participants stated that they were able to fully meet the course objectives. Test scores among the convenience sample averaged 88% 2 weeks after training.

CONCLUSIONS

The use of self-paced stations for tuberculosis respirator training and employee tuberculosis skin test screening was both effective and time-efficient for employees. We have expanded this program to include all of our approximately 500 employees who may be exposed to tuberculosis.