Variability in weather and site properties affect fuel and fire behavior following fuel treatments in semiarid sagebrush-steppe

Fuel-treatments targeting shrubs and fire-prone exotic annual grasses (EAGs) are increasingly used to mitigate increased wildfire risks in arid and semiarid environments, and understanding their response to natural factors is needed for effective landscape management. Using field-data collected over four years from fuel-break treatments in semiarid sagebrush-steppe, we asked 1) how the outcomes of EAG and sagebrush fuel treatments varied with site biophysical properties, climate, and weather, and 2) how predictions of fire behavior using the Fuel Characteristic Classification System fire model related to land-management objectives of maintaining fire behavior expected of low-load, dry-climate grasslands. Generalized linear mixed effect modeling with build-up model selection was used to determine best-fit models, and marginal effects plots to assess responses for each fuel type. EAG cover decreased as antecedent-fall precipitation increased and increased as antecedent-spring temperatures and surface soil clay contents increased. Herbicides targeting EAGs were less effective where pre-treatment EAG cover was >40 % and antecedent spring temperatures were >9.5 °C. Sagebrush cover was inversely related to soil clay content, especially where clay contents were >17 %. Predicted fire behavior exceeded management objectives under 1) average fire weather conditions when EAG or sagebrush cover was >50 % or >26 %, respectively, or 2) extreme fire weather conditions when EAG or sagebrush cover was >10 % or >8 %, respectively. Consideration of the strong effects of natural variability in site properties and antecedent weather can help in justifying, planning and implementing fuel-treatments.

OS07.2.A Evaluation of Intraoperative Surgical Adjuncts and Resection of Glioblastoma (ELISAR GB): A UK and Ireland multicentre, prospective observational cohort study

Background

Despite operative and adjuvant therapies, glioblastoma remains incurable, with the extent of resection being one of few treatments that can improve survival. To improve resection, operative adjuncts are used, with neuronavigation and 5-aminolevulinic acid (5-ALA) recommended as a standard of care in those aimed for maximal safe resection. Despite the standards, meta-analysis concluded that the impact of 5-ALA on the extent of surgical resection is of low quality due to bias in reporting tumour location and additional image guidance used, factors impacting on extent of resection as well as short-term neurological outcomes being uncertain. Therefore we aimed to evaluate the availability and use of 5-ALA and other adjuncts and compare surgical outcomes of 5-ALA-guided versus non-5-ALA-guided resections.

Material and Methods

A multicenter prospective observational cohort study was conducted across 27 out of 31 available centres in the UK and Ireland from 6 January until 19 March 2020. Inclusion criteria included adults with first diagnosis, supratentorial glioblastoma undergoing resection. Primary outcomes included: i) the availability and use of surgical adjuncts and ii) complete resection of enhancing tissue (CRET). Secondary outcomes included adverse events, new onset of postoperative neurological deficit and post-operative neurological function. Descriptive and inferential statistics were used for analysis with a p-value <0.05 deemed significant.

Results

232 consecutive cases were identified. 142/232 cases were aimed for maximal safe resection subsequently divided into 5-ALA-guided (n=92) versus non-5-ALA-guided (n=50) resections. 5-ALA and neuronavigation were available across all centres. Neuronavigation and 5-ALA were used in 91% (n=129/142) and 65% (n=92/142) of cases aimed for maximal safe resection whereas 83% (n=75/90) and 49% (n=44/90) for debulk surgery. 35 unique combinations of surgical adjuncts were used in 232 operations. 5-ALA-guided resection yielded a higher percentage of CRET than without (55% versus 28%, p < 0.01). The two groups showed no difference in adverse events (p=0.98), new onset of neurological deficit (p=0.88) nor neurological function (p=0.7). A logistic regression analysis showed that 5-ALA was an important predictor of CRET regardless of additional adjuncts used (OR 2.4, CI 0.96-5.97, P = 0.05), tumour location and molecular characterisation (OR 3.48, CI 1.61-7.51, P <0.01).

Conclusion

Firstly, we showed that 5-ALA is not always used for glioblastoma aimed for CRET. Secondly, we report a great heterogeneity of adjuncts used for resection, possibly explained by a lack of high-quality evidence and surgeon training. Thirdly we demonstrate that 5-ALA-guided resection leads to higher percentage of CRET regardless of other adjuncts used, tumour location and molecular characterisation.

P15.07.A Predicting sites of local tumour progression - what should be our imaging biomarker?

Background

Glioblastoma is the most aggressive primary brain tumour diagnosed in adults. Despite intensive treatment of maximal safe resection and chemoradiotherapy, the prognosis remains grim due to invasive tumour cells. Current treatment and standard imaging methods are highly limited in terms of managing these invasive cells as they are often located outside the area of surgical resection and are generally resistant to chemoradiation. DTI appears to be a promising tool for imaging tumour cell invasion and predicting the site of recurrence especially when decomposed into its anisotropic (q) and isotropic (p) components. The aim of this study is to investigate the sensitivity of imaging biomarkers as predictors of recurrence.

Material and Methods

All pre-op and recurrence sequences were co-registered to the pre-op post-contrast T1-weighted images as reference. Co-registration of images was performed using FSL and ANTs. The ROIs for 49 patients with a primary diagnosis of GBM were segmented using 3DSlicer. Each voxel was assigned to one of four status: true negative, false negative, true positive and false positive. Sensitivity and specificity between the pre-op ROIs and the progression region were calculated using FSL. The significance of the differences in sensitivity and specificity between the ROIs was computed in MATLAB.

Results

The sensitivity for the contrast enhancing region was 48.77 ± 26.13 (Mean ± SD) and 62.40 ± 23.07 (Mean ± SD). The abnormal q alone has a significantly greater sensitivity than the contrast enhancing region (t = -2.7327, df = 96, p-value = 0.0075). The sensitivity for the ROI of combined contrast enhancement and abnormal q was 65.86 ± 23.29 (Mean ± SD). There is an even more significant increase in sensitivity when the contrast enhancing ROI is combined with abnormal q region (t = -3.4133, df = 96, p-value = 9.4123e-04) compared to when it is alone. There was no statistical difference in the specificities of the different ROIs.

Conclusion

Current surgical and radiation volumes focus solely on pre-op contrast enhancement. However, these results suggest that combining the abnormal q with the standard contrast enhancing region is a more sensitive predictor of tumour recurrence than contrast enhancement alone, while still retaining high specificity. The higher sensitivity is an indicator of correct identification of tumour recurrence while the high specificity correctly identifies normal brain, or non-recurrent regions. These results are currently being prospectively assessed in a multi-centre study (PRaM-GBM).

P14.129 Predicting glioblastoma invasion using multiparametric MRI and a bi-level machine learning approach

BACKGROUND

Glioblastoma is characterized by its extensive infiltration into the brain parenchyma, which poses challenges to accurate treatment volume targeting. Current treatment planning is based on the contrast-enhancing images. Tumor invasion, however, is well known beyond the contrast enhancement. Although deep learning shows potential in delineating tumor invasion based on multiparametric MRI, it requires large amount of training data. Image inpainting may reconstruct the lost image information based on image structure and requires less training data. The purpose of this study is to investigate whether a bi-level deep learning approach could integrate conventional neural network (CNN) and image inpainting to delineate tumor invasion based on the multiparametric MRI.

MATERIAL AND METHODS

A total of 115 patients (mean age 59.3 yrs, range 22 - 76 yrs, 87 males) with supratentorial de novo glioblastoma were recruited for maximal safe tumor resection. Post-operative temozolomide chemoradiotherapy was performed following the Stupp protocol. The Response Assessment in Neuro-oncology criteria was used to evaluate patient response. All MRI sequences were pre-operatively acquired using a 3T scanner, including T2-weighted, post-contrast T1-weighted, FLAIR, dynamic susceptibility contrast (DSC) and diffusion tensor imaging (DTI). The isotropic (p) and anisotropic (q) maps were generated from DTI. The relative cerebral blood volume (rCBV), mean transit time (MTT) and relative cerebral blood flow (rCBF) were generated from the DSC images after the leakage correction. All images were coregistered to post-contrast T1W images. Contrast-enhancing (CE) and non-enhancing (NE) regions were semi-automatically segmented and validated by an experienced neuro-radiologist. A tissue segmentation was performed using the FAST (FMRIB’s Automated Segmentation Tool) to segment the normal-appearing brain excluding the above both tumor regions and were classified into three tissue types (grey matter, white matter and CSF). A CNN model was applied to build a classification function between the CE region and the three normal-appearing tissue types based on the multi-parametric MRI. A bespoke inpainting scheme was then applied to predict the tumor invasion area in the NE region. Kaplan-Meier and Cox proportional regression were used to evaluate the significance of the predicted volume.

RESULTS

The volumes of the contrast-enhancing tumor is 53.6 ± 33.8 cm3. The predicted invasive volume in the non-enhancing region is 31.0 ± 17.7 cm3.The multivariate model shows that the predicted volume was significantly associated with OS (HR = 0.97, P= 0.006). The patient subgroup with a higher predicted volume showed significantly better OS (P= 0.009) and PFS (P= 0.021).

CONCLUSION

The proposed bi-level deep learning approach may effectively integrate multiparametric MRI for predicting tumor invasio.

Diagnostic Accuracy of Neuroimaging to Delineate Diffuse Gliomas within the Brain: A Meta-Analysis

BACKGROUND

Brain imaging in diffuse glioma is used for diagnosis, treatment planning, and follow-up.

PURPOSE

In this meta-analysis, we address the diagnostic accuracy of imaging to delineate diffuse glioma.

DATA SOURCES

We systematically searched studies of adults with diffuse gliomas and correlation of imaging with histopathology.

STUDY SELECTION

Study inclusion was based on quality criteria. Individual patient data were used, if available.

DATA ANALYSIS

A hierarchic summary receiver operating characteristic method was applied. Low- and high-grade gliomas were analyzed in subgroups.

DATA SYNTHESIS

Sixty-one studies described 3532 samples in 1309 patients. The mean Standard for Reporting of Diagnostic Accuracy score (13/25) indicated suboptimal reporting quality. For diffuse gliomas as a whole, the diagnostic accuracy was best with T2-weighted imaging, measured as area under the curve, false-positive rate, true-positive rate, and diagnostic odds ratio of 95.6%, 3.3%, 82%, and 152. For low-grade gliomas, the diagnostic accuracy of T2-weighted imaging as a reference was 89.0%, 0.4%, 44.7%, and 205; and for high-grade gliomas, with T1-weighted gadolinium-enhanced MR imaging as a reference, it was 80.7%, 16.8%, 73.3%, and 14.8. In high-grade gliomas, MR spectroscopy (85.7%, 35.0%, 85.7%, and 12.4) and ¹¹C methionine-PET (85.1%, 38.7%, 93.7%, and 26.6) performed better than the reference imaging.

LIMITATIONS

True-negative samples were underrepresented in these data, so false-positive rates are probably less reliable than true-positive rates. Multimodality imaging data were unavailable.

CONCLUSIONS

The diagnostic accuracy of commonly used imaging is better for delineation of low-grade gliomas than high-grade gliomas on the basis of limited evidence. Improvement is indicated from advanced techniques, such as MR spectroscopy and PET.

Factors affecting temperature variation and habitat use in free-ranging diamondback terrapins

Measuring the thermal conditions of aquatic reptiles with temperature dataloggers is a cost-effective way to study their behavior and habitat use. Temperature dataloggers are a particularly useful and informative approach to studying organisms such as the estuarine diamondback terrapin (Malaclemys terrapin) that inhabits a dynamic environment often inaccessible to researchers. We used carapace-mounted dataloggers to measure hourly carapace temperature (Tc) of free-ranging terrapins in South Carolina from October 2007 to 2008 to examine the effects of month, sex, creek site, and tide on Tc and to determine the effects of month, sex, and time of day on terrapin basking frequency. Simultaneous measurements of environmental temperatures (Te; shallow mud, deep mud, water) allowed us to make inferences about terrapin microhabitat use. Terrapin Tc differed significantly among months and creek and between sexes. Terrapin microhabitat use also varied monthly, with shallow mud temperature being the best predictor of Tc November-March and water temperature being the best predictor of Tc April-October. Terrapins basked most frequently in spring and fall and males basked more frequently than females. Our study contributes to a fuller understanding of terrapin thermal biology and provides support for using dataloggers to investigate behavior and habitat use of aquatic ectotherms inhabiting dynamic environments.

Current concepts in the surgical management of glioma patients

The scientific basis for the surgical management of patients with glioma is rapidly evolving. The infiltrative nature of these cancers precludes a surgical cure, but despite this, cytoreductive surgery remains central to high-quality patient care. In addition to tissue sampling for accurate histopathological diagnosis and molecular genetic characterisation, clinical benefit from decompression of space-occupying lesions and microsurgical cytoreduction has been reported in patients with different grades of glioma. By integrating advanced surgical techniques with molecular genetic characterisation of the disease and targeted radiotherapy and chemotherapy, it is possible to construct a programme of personalised surgical therapy throughout the patient journey. The goal of therapeutic packages tailored to each patient is to optimise patient safety and clinical outcome and must be delivered in a multidisciplinary setting. Here we review the current concepts that underlie surgical subspecialisation in the management of patients with glioma.

Methodology of diffusion-weighted, diffusion tensor and magnetisation transfer imaging

MRI offers a number of opportunities to examine characteristics of tissue well below the spatial resolution of the imaging technique. The best known of these is diffusion imaging, which allows the production of images whose contrast reflects the ability of water molecules to move through the extravascular extracellular space. Less well-known, but increasingly important, is magnetisation transfer imaging, which produces contrast based on the ability of protons to move between the free water pool and local macromolecules. Both of these techniques offer unique information about the microscopic and molecular structure of tumour tissue. This article will briefly review the underlying theory and technical aspects associated with these imaging techniques.

Fluorescence-guided surgical sampling of glioblastoma identifies phenotypically distinct tumour-initiating cell populations in the tumour mass and margin

BACKGROUND

Acquiring clinically annotated, spatially stratified tissue samples from human glioblastoma (GBM) is compromised by haemorrhage, brain shift and subjective identification of 'normal' brain. We tested the use of 5-aminolevulinic acid (5-ALA) fluorescence to objective tissue sampling and to derive tumour-initiating cells (TICs) from mass and margin.

METHODS

The 5-ALA was administered to 30 GBM patients. Samples were taken from the non-fluorescent necrotic core, fluorescent tumour mass and non-fluorescent margin. We compared the efficiency of isolating TICs from these areas in 5-ALA versus control patients. HRMAS (1)H NMR was used to reveal metabolic alterations due to 5-ALA. We then characterised TICs for self-renewal in vitro and tumorigenicity in vivo.

RESULTS

The derivation of TICs was not compromised by 5-ALA and the metabolic profile was similar between tumours from 5-ALA patients and controls. The TICs from the fluorescent mass were self-renewing in vitro and tumour-forming in vivo, whereas TICs from non-fluorescent margin did not self-renew in vitro but did form tumours in vivo.

CONCLUSION

Our data show that 5-ALA does not compromise the derivation of TICs. It also reveals that the margin contains TICs, which are phenotypically different from those isolated from the corresponding mass.

Decision forests for tissue-specific segmentation of high-grade gliomas in multi-channel MR

We present a method for automatic segmentation of high-grade gliomas and their subregions from multi-channel MR images. Besides segmenting the gross tumor, we also differentiate between active cells, necrotic core, and edema. Our discriminative approach is based on decision forests using context-aware spatial features, and integrates a generative model of tissue appearance, by using the probabilities obtained by tissue-specific Gaussian mixture models as additional input for the forest. Our method classifies the individual tissue types simultaneously, which has the potential to simplify the classification task. The approach is computationally efficient and of low model complexity. The validation is performed on a labeled database of 40 multi-channel MR images, including DTI. We assess the effects of using DTI, and varying the amount of training data. Our segmentation results are highly accurate, and compare favorably to the state of the art.

Imaging biomarkers of brain tumour margin and tumour invasion

Invasion of tumour cells into the normal brain is one of the major reasons of treatment failure for gliomas. Although there is a good understanding of the molecular and cellular processes that occur during this invasion, it is not possible to detect the extent of the tumour with conventional imaging. However, there is an understanding that the degree of invasion differs with individual tumours, and yet they are all treated the same. Newer imaging techniques that probe the pathological changes within tumours may be suitable biomarkers for invasion. Imaging methods are now available that can detect subtle changes in white matter organisation (diffusion tensor imaging), tumour metabolism and cellular proliferation (using MR spectroscopy and positron emission tomography) occurring in regions of tumour that cannot be detected by conventional imaging. The role of such biomarkers of invasion should allow better delineation of tumour margins, which should improve treatment planning (especially surgery and radiotherapy) and provide information on the invasiveness of an individual tumour to help select the most appropriate therapy and help stratify patients for clinical trials.

Implementation of neuro-oncology service reconfiguration in accordance with NICE guidance provides enhanced clinical care for patients with glioblastoma multiforme

Background:

Brain tumours account for <2% of all primary neoplasms but are responsible for 7% of the years of life lost from cancer before age 70 years. The latest survival trends for patients with CNS malignancies have remained largely static. The objective of this study was to evaluate the change in practice as a result of implementing the Improving Outcomes Guidance from the UK National Institute for Health and Clinical Excellence (NICE).

Methods:

Patients were identified from the local cancer registry and hospital databases. We compared time from diagnosis to treatment, proportion of patients discussed at multidisciplinary team (MDT) meetings, treatment received, length of inpatient stay and survival. Inpatient and imaging costs were also estimated.

Results:

Service reconfiguration and implementation of NICE guidance resulted in significantly more patients being discussed by the MDT—increased from 66 to 87%, reduced emergency admission in favour of elective surgery, reduced median hospital stay from 8 to 4.5 days, increased use of post-operative MRI from 17 to 91% facilitating early discharge and treatment planning, and reduced cost of inpatient stay from £2096 in 2006 to £1316 in 2009. Patients treated with optimal surgery followed by radiotherapy with concomitant and adjuvant temozolomide achieved outcomes comparable to those reported in clinical trials: median overall survival 18 months (2-year survival 35%).

Conclusions:

Advancing the management of neuro-oncology patients by moving from an emergency-based system of patient referral and management to a more planned elective outpatient-based pattern of care improves patient experience and has the potential to deliver better outcomes and research opportunities.

Correlation of MR relative cerebral blood volume measurements with cellular density and proliferation in high-grade gliomas: an image-guided biopsy study

BACKGROUND AND PURPOSE

As newer MR imaging techniques are used to assist with tumor grading, biopsy planning, and therapeutic response assessment, there is a need to relate the imaging characteristics to underlying pathologic processes. The aim of this study was to see how rCBV, a known marker of tumor vascularity, relates to cellular packing attenuation and cellular proliferation.

MATERIALS AND METHODS

Nine patients with histologically proved high-grade gliomas and 1 with a supratentorial PNET requiring an image-guided biopsy were recruited. Patients underwent a DSC study. The rCBV at the intended biopsy sites was determined by using a histogram measure to derive the mean, maximum, and 75th centile and 90th centile values. This measure was correlated with histologic markers of the MIB-1 labeling index (as a marker of glioma cell proliferation) and the total number of neoplastic cells in a high-power field (cellular packing attenuation).

RESULTS

There was a good correlation between rCBV and MIB-1 by using all the measures of rCBV. The mean rCBV provided the best results (r = 0.66, P < .001). The only correlation with cellular packing attenuation was with the 90% centile (rCBV(90%), r = 0.36, P = .03). The increase in rCBV could be seen over 1 cm from the edge of enhancement in 4/10 cases, and at 2 cm in 1/10.

CONCLUSIONS

rCBV correlated with cellular proliferation in high-grade gliomas but not with cellular packing attenuation. The increase in rCBV extended beyond the contrast-enhancing region in 50% of our patients.

Radiotherapy as an adjuvant in the management of intracranial meningiomas: are we practising evidence-based medicine?

Although increasingly used, the precise role of radiotherapy in the management of meningiomas is still disputed. The objective of this study, therefore, was to appraise the evidence for adjuvant radiotherapy in benign and atypical intracranial meningiomas, and to compare and contrast it with the current opinion and practice of neurosurgeons in the United Kingdom and the Republic of Ireland. The use of radiotherapy as a primary treatment strategy or its use in the treatment of recurrence was not considered. We performed a systematic review of the evidence for adjuvant radiotherapy in benign and atypical intracranial meningiomas, surveyed current opinion amongst neurosurgeons involved in such cases and ascertained local practice using data from the regional cancer registry. Overall, 10 cohorts were identified that fulfilled our eligibility criteria. Four studies showed significantly improved local control in patients receiving adjuvant radiotherapy for incompletely resected grade I meningiomas. Our survey demonstrated that the vast majority (98%) of neurosurgeons would not recommend adjuvant radiotherapy in grade I meningioma. In grade II meningioma, most (80%) would not advocate adjuvant radiotherapy if completely excised, but the majority (59%) would recommend radiotherapy in cases of subtotal resection. Significant variation in opinion between centres exists, however, particularly in cases of completely resected atypical meningiomas (p = 0.02). Data from the Eastern Cancer Registration and Information Centre appears to be in line with these findings: less than 10% of patients with grade I meningiomas, but almost 30% of patients with grade II meningiomas received adjuvant radiotherapy in the Eastern region. In conclusion, our study has highlighted significant variation in opinion and practice, reflecting a lack of class 1 evidence to support the use of adjuvant radiotherapy in the treatment of meningiomas. Efforts are underway to address this with a randomized multicentre trial comparing a policy of watchful waiting versus adjuvant irradiation.

Early radiotherapy dose response and lack of hypersensitivity effect in normal brain tissue: a sequential dynamic susceptibility imaging study of cerebral perfusion

AIMS

To determine if magnetic resonance perfusion markers can be used as an analytical marker of subclinical normal brain injury after radiotherapy, by looking for a dose-effect relationship.

MATERIALS AND METHODS

Four patients undergoing conformal radiotherapy to 54Gy in 30 fractions for low-grade gliomas were imaged with conventional T(2)-weighted and fluid attenuated inversion recovery imaging as well as dynamic contrast susceptibility perfusion imaging. Forty regions of interest were determined from the periventricular white matter. All conventional sequences were examined for evidence of radiation-induced changes. Patients were imaged before radiotherapy, after one fraction, at the end of treatment and then at 1 and 3 months from the end of radiotherapy. For each region the relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF) and mean transit time (MTT) expressed as a ratio of the baseline value, and radiotherapy dose were determined.

RESULTS

Of the 40 regions, seven occurred within the gross tumour volume and a further four occurred in regions later infiltrated by tumour, and were thus excluded. Regions within the 80% isodose showed a reduction in rCBV and rCBF over the 3 month period. There was no significant alteration in rCBV or rCBF in regions outside the 60% isodose (i.e. <32Gy). MTT did not alter in any region. There seemed to be a threshold effect at 132 days from the end of radiotherapy of 47% (standard error of the mean 11.5, about 25.4Gy) for rCBV and 59% (standard error of the mean 14.2, about 31.9Gy) for rCBF.

CONCLUSIONS

There was a dose-related reduction in rCBV and rCBF in normal brain after radiotherapy at higher dose levels. Although this study used a limited number of patients, it suggests that magnetic resonance perfusion imaging seems to act as a marker of subclinical response of normal brain and that there is an absence of an early hypersensitivity effect with small doses per fraction. Further studies are required with larger groups of patients to show that these results are statistically robust.

Improved delineation of glioma margins and regions of infiltration with the use of diffusion tensor imaging: an image-guided biopsy study

BACKGROUND AND PURPOSE

The efficacy of radiation therapy, the mainstay of treatment for malignant gliomas, is limited by our inability to accurately determine tumor margins. As a result, despite recent advances, the prognosis remains appalling. Because gliomas preferentially infiltrate along white matter tracks, methods that show white matter disruption should improve this delineation. In this study, results of histologic examination from samples obtained from image-guided brain biopsies were correlated with diffusion tensor images.

METHODS

Twenty patients requiring image-guided biopsies for presumed gliomas were imaged preoperatively. Patients underwent image-guided biopsies with multiple biopsies taken along a single track that went into normal-appearing brain. Regions of interest were determined from the sites of the biopsies, and diffusion tensor imaging findings were compared with glioma histology.

RESULTS

Using diffusion tissue signatures, it was possible to differentiate gross tumor (reduction of the anisotropic component, q > 12% from contralateral region), from tumor infiltration (increase in the isotropic component, p > 10% from contralateral region). This technique has a sensitivity of 98% and specificity of 81%. T2-weighted abnormalities failed to identify the margin in half of all specimens.

CONCLUSION

Diffusion tensor imaging can better delineate the tumor margin in gliomas. Such techniques can improve the delineation of the radiation therapy target volume for gliomas and potentially can direct local therapies for tumor infiltration.

Characterization of an analphoid supernumerary marker chromosome derived from 15q25-->qter using high-resolution CGH and multiplex FISH analyses

Supernumerary marker chromosomes (SMCs) without detectable alphoid DNA are predicted to have a neocentromere and have been referred to as mitotically stable neocentromere marker chromosomes (NMCs). We report the molecular cytogenetic characterization of a new case with analphoid NMC derived from 15q25-->qter using high-resolution comparative genomic hybridization (HR-CGH) and multiplex fluorescence in situ hybridization analyses with various alpha-satellite DNA probes, all-human-centromere probe (AHC), whole chromosome painting probes, and a subtelomere probe. The propositus is a dysmorphic infant who, at age 3 months, showed accelerated growth, partial deafness, and a phenotype similar to that of the eight previously reported cases of distal 15q tetrasomy. Chromosome studies showed that he had a de novo extra SMC in 80% of cells examined. HR-CGH revealed rev ish enh(15)(q25qter). Molecular cytogenetic analysis and molecular DNA polymorphism study demonstrated that this extra SMC is an NMC containing an inverted duplication of the distal long arm of chromosome 15 (tetrasomy 15q25-->qter) which originated paternally, i.e. ish der(15)(qte-->q25::q25[neocen]-->qter)(AHC-, CEP15-, WCP15+, PCP15q++). This case further elucidates the phenotype related to tetrasomy of this specific chromosome segment and represents a new report of a neocentromere on distal chromosome 15q suggesting that this region appears to be susceptible to the formation of neocentromeres.

Enhanced visualization and quantification of magnetic resonance diffusion tensor imaging using the p:q tensor decomposition

Many scalar measures have been proposed to quantify magnetic resonance diffusion tensor imaging (MR DTI) data in the brain. However, only two parameters are commonly used in the literature: mean diffusion (D) and fractional anisotropy (FA). We introduce a visualization technique which permits the simultaneous analysis of an additional five scalar measures. This enhanced diversity is important, as it is not known a priori which of these measures best describes pathological changes for brain tissue. The proposed technique is based on a tensor transformation, which decomposes the diffusion tensor into its isotropic (p) and anisotropic (q) components. To illustrate the use of this technique, diffusion tensor imaging was performed on a healthy volunteer, a sequential study in a patient with recent stroke, a patient with hydrocephalus and a patient with an intracranial tumour. Our results demonstrate a clear distinction between different anatomical regions in the normal volunteer and the evolution of the pathology in the patients. In the normal volunteer, the brain parenchyma values for p and q fell into a narrow band with 0.976<p<1.063 x 10(-3) mm2 s(-1) and 0.15<q<1.08 x 10(-3) mm2 s(-1). The noise appeared as a compact cluster with (p,q) components (0.011, 0.141) x 10(-3) mm2 s(-1), while the cerebrospinal fluid was (3.320, 0.330) x 10(-3) mm2 s(-1). In the stroke patient, the ischaemic area demonstrated a trajectory composed of acute, sub-acute and chronic phases. The components of the lesion were (0.824, 0.420), (0.884, 0.254), (2.624, 0.325) at 37 h, 1 week and 1 month, respectively. The internal capsule of the hydrocephalus patient demonstrated a larger dispersion in the p:q plane suggesting disruption. Finally, there was clear white matter tissue destruction in the tumour patient. In summary, the p:q decomposition enhances the visualization and quantification of MR DTI data in both normal and pathological conditions.

Diffusion tensor imaging: possible implications for radiotherapy treatment planning of patients with high-grade glioma

AIMS

Radiotherapy treatment planning for high-grade gliomas (HGG) is hampered by the inability to image peri-tumoural white-matter infiltration. Diffusion tensor imaging (DTI) is an imaging technique that seems to show white-matter abnormalities resulting from tumour infiltration that cannot be visualised by conventional computed tomography or magnetic resonance imaging (MRI). We propose a new term, the image-based high-risk volume (IHV) for such abnormalities, which are distinct from the gross-tumour volume (GTV). For IHV based on DTI, we use the term IHVDTI. This study assesses the value of DTI for the individualisation of radiotherapy treatment planning for patients with HGG.

METHODS

Seven patients with biopsy-proven HGG were included in a theoretical planning exercise, comparing standard planning techniques with individualised plans based on DTI. Standard plans were generated using a 2.5 cm clinical target volume (CTV) margin added to the GTV. For DTI-based plans, the CTV was generated by adding a 1 cm margin to the IHVDTI. Estimates of normal tissue complication probability (NTCP) were calculated and used to estimate the level of dose escalation that could be achieved using the DTI-based plans.

RESULTS

The use of DTI resulted in non-uniform margins being added to the GTV to encompass areas at high risk of tumour involvement, but, in six out of seven cases, the IHVDTI was encapsulated by the standard CTV margin. In all cases, DTI could be used to reduce the size of the planning-target volume (PTV) (mean 35%, range 18-46%), resulting in escalated doses (mean 67 Gy, range 64-74 Gy), with NTCP levels that matched the conventional treatment plans.

CONCLUSION

DTI can be used to individualise radiotherapy target volumes, and reduction in the CTV permits modest dose escalation without an increase in NTCP. DTI may also be helpful in stratifying patients according to the degree of white-matter infiltration.

Detection and evaluation of intracranial aneurysms with 16-row multislice CT angiography

AIM

The aim of this study was to assess the usefulness of 16-row multislice CT angiography (CTA) in evaluating intracranial aneurysms, by comparison with conventional digital subtraction angiography (DSA) and intraoperative findings.

METHODS

A consecutive series of 57 patients, scheduled for DSA for suspected intracranial aneurysm, was prospectively recruited to have CTA. This was performed with a 16-detector row machine, detector interval 0.75 mm, 0.5 rotation/s, table speed 10mm/rotation and reconstruction interval 0.40 mm. CTA studies were independently and randomly assessed by two neuroradiologists and a vascular neurosurgeon blinded to the DSA and surgical findings. Review of CTA was performed on workstations with an interactive 3D volume-rendered algorithm.

RESULTS

DSA or intraoperative findings or both confirmed 53 aneurysms in 44 patients. For both independent readers, sensitivity and specificity per aneurysm of DSA were 96.2% and 100%, respectively. Sensitivity and specificity of CTA were also 96.2% and 100%, respectively. Mean diameter of aneurysms was 6.3mm (range 1.9 to 28.1 mm, SD 5.2 mm). For aneurysms of less than 3 mm, CTA had a sensitivity of 91.7% for each reader. Although the neurosurgeon would have been happy to proceed to surgery on the basis of CTA alone in all cases, he judged that DSA might have provided helpful additional anatomical information in 5 patients.

CONCLUSION

The diagnostic accuracy of 16-slice CTA is promising and appears equivalent to that of DSA for detection and evaluation of intracranial aneurysms. A strategy of using CTA as the primary imaging method, with DSA reserved for cases of uncertainty, appears to be practical and safe.

Detecting glioma invasion of the corpus callosum using diffusion tensor imaging

We present a patient with a recurrent glioblastoma and abnormalities of the corpus callosum seen on diffusion tensor MRI that were not seen on conventional imaging. These abnormalities preceded the development of the tumour. We describe the technique of diffusion tissue signatures to assess tissue infiltration by tumours compared with values from normal volunteers.

Diffusion tensor imaging of brain tumours at 3T: a potential tool for assessing white matter tract invasion?

AIM

To determine whether diffusion tensor imaging (DTI) of brain tumours can demonstrate abnormalities distal to hyperintensities on T2-weighted images, and possibly relate these to tumour grade.

MATERIALS AND METHODS

Twenty patients with histologically confirmed supratentorial tumours, both gliomas (high and low grade) and metastases, were imaged at 3T using T2-weighted and DTI sequences. Regions of interest (ROI) were drawn within the tumour, in white matter at various distances from the tumour and in areas of abnormality on DTI that appeared normal on T2-weighted images. The relative anisotropy index (RAI)-a measure of white matter organization, was calculated for these ROI.

RESULTS

The abnormality on DTI was larger than that seen on T2-weighted images in 10/13 patients (77%) with high-grade gliomas. New abnormalities were seen in the contralateral white matter in 4/13 (30%) of these cases. In these high-grade tumours the RAI in areas of white matter disruption with normal appearance on T2-weighted images was reduced (0.19+/-0.04). Even excluding patients with previous radiotherapy this difference remains significant. In all non high-grade tumours (WHO grade II gliomas and metastases) the tumour extent on DTI was identical to the abnormalities shown on T2-weighted imaging and RAI measurements were not reduced (0.3+/-0.04).

CONCLUSIONS

Subtle white matter disruption can be identified using DTI in patients with high-grade gliomas. Such disruption is not identified in association with metastases or low-grade gliomas despite these tumours producing significant mass effect and oedema. We suggest the changes in DTI may be due to tumour infiltration and that the DTI may provide a useful method of detecting occult white matter invasion by gliomas.

Characterization of the region containing the jcpk PKD gene on mouse Chromosome 10

The jcpk gene on mouse Chromosome 10 causes a severe, early onset form of polycystic kidney disease (PKD) when inherited in an autosomal recessive manner. In order to positionally clone this gene, high resolution genetic and radiation hybrid maps were generated along with a detailed physical map of the approximately 500-kb region containing the jcpk gene. Additionally, sixty-nine kidney-specific ESTs were evaluated as candidates for jcpk and subsequently localized throughout the mouse genome by radiation hybrid mapping analysis. Previous studies indicating non-complementation of the jcpk mutation and 67Gso, a new PKD translocation mutant had suggested that 67Gso represents a new allele of jcpk. Fluorescence in situ hybridization (FISH) analysis using key bacterial artificial chromosome clones from the jcpk critical region, refined the 67Gso breakpoint and provided support for the allelism of jcpk and 67Gso.

Arachnoid cyst of the craniocervical junction: case report

OBJECTIVE AND IMPORTANCE

An arachnoid cyst at the craniocervical junction presenting with obstructive hydrocephalus as a result of blockage of the outflow of the fourth ventricle is described. This is a very rare anatomic site, with only five other cases described in the literature.

CLINICAL PRESENTATION

A 37-year-old woman presented with a 9-month history of severe neck pain, persistent vomiting, visual disturbances, and numbness of the nose, cheek, and lips. She had severe bilateral papilledema on ophthalmoscopy. Magnetic resonance imaging revealed a midline cystic lesion extending down to C2.

INTERVENTION

The patient underwent posterior fossa craniectomy and excision of the arachnoid cyst. She made a full recovery and was asymptomatic at follow-up examination.

CONCLUSION

The symptomatology of these rare craniocervical arachnoid cysts and their development are discussed.

Identification of novel, functional genetic variants in the human matrix metalloproteinase-2 gene: role of Sp1 in allele-specific transcriptional regulation

Matrix metalloproteinase-2 (MMP-2) is an enzyme with proteolytic activity against matrix and nonmatrix proteins, particularly basement membrane constituents. Thus, any naturally occurring genetic variants that directly affect gene expression and/or protein function would be expected to impact on progression of pathological processes involving tissue remodeling. We scanned a 2-kilobase pair promoter region and all 13 exons of the human MMP-2 gene, from a panel of 32 individuals, and we identified the position, nature, and relative allele frequencies of 15 variant loci as follows: 6 in the promoter, 1 in the 5'-untranslated region, 6 in the coding region, 1 in intronic sequence, and 1 in the 3'-untranslated region. The majority of coding region polymorphisms resulted in synonymous substitutions, whereas three promoter variants (at -1306, -790, and +220) mapped onto cis-acting elements. We functionally characterized all promoter variants by transient transfection experiments with 293, RAW264.7, and A10 cells. The common C --> T transition at -1306 (allele frequency 0.26), which disrupts an Sp1-type promoter site (CCACC box), displayed a strikingly lower promoter activity with the T allele. Electrophoretic mobility shift assays confirmed that these differences in allelic expression were attributable to abolition of Sp1 binding. These data suggest that this common functional genetic variant influences MMP-2 gene transcription in an allele-specific manner and is therefore an important candidate to test for association in a wide spectrum of pathologies for which a role for MMP-2 is implicated, including atherogenesis and tumor invasion and metastasis.

Are goals and topics influenced by gender and modality in the initial marriage and family therapy session?

Establishment of a goal is crucial to therapy, but identification of therapeutic goals may be difficult in conjoint therapy because each participant may identify a different problem. We examined the influence of gender on ability to successfully introduce therapeutic topics in marital and family therapy by conducting two studies. The first study evaluates the ability of therapists to identify therapeutic goals that matched goals prioritized by both women and men clients on pretherapy questionnaires. The second study examines the process of initial therapy sessions to see whether gender influences a client's ability to introduce a therapeutic topic. Results suggest that therapeutic topic is influenced by the interaction of gender and treatment modality. Specifically, therapists were better able to match women's pretherapy stated goals in marital therapy than family therapy, men were more successful at introducing topics in family therapy, and women were more successful at introducing topics in marital therapy.

Adynamic ileus complicating lumbar laminectomy: a report of two cases

Adynamic ileus is a well recognized complication of spinal injuries and disease. We report two cases of adynamic ileus affecting both small and large bowel following uncomplicated L4/5 laminectomy. Both patients recovered with conservative treatment, but their hospital stay was prolonged. We have found three other cases in the literature of ileus affecting only the colon following laminectomy at this same level.

Use of contraception in women who present for termination of pregnancy in inner London

OBJECTIVES

To describe the contraceptive usage of women undergoing termination of pregnancy in order to identify problems with contraception, and therefore suggest ways in which contraceptive services can be improved.

DESIGN

Prospective study of attenders for NHS termination of pregnancy over a three month period.

SETTING

Community based assessment clinics for NHS termination of pregnancy in inner London.

SUBJECTS

Two hundred and sixty-nine women asking for assessment for NHS termination of pregnancy.

MAIN OUTCOME MEASURES

Source of contraception, method used around time of conception, and problems experienced.

RESULTS

Respondents tell into three groups: those using contraception around the time they became pregnant; those who had ceased to use contraception; and those that had never used contraception. The method of contraception used by the majority of the first group was the condom and the main source of the method was the chemist shop. The second group had most commonly used oral contraceptives in the past and had ceased use in many cases as a result of side effects. The majority of the third group did not speak English and had limited knowledge of methods of contraception.

CONCLUSIONS

High usage of chemists means women avoid service providers who could offer help and advice. Women were prepared to put themselves at risk of unwanted pregnancy rather than return for further help and the lack of knowledge about emergency birth control was of some concern. The needs of black and ethnic minority women requires detailed work to improve access and acceptability of contraceptive services.

Medial antebrachial cutaneous nerve conduction in true neurogenic thoracic outlet syndrome

Thoracic outlet syndrome (TOS) and its diagnosis have been topics of controversy, fueled in part by the lack of an objective test for early diagnosis. True neurogenic TOS results in diagnostic EMG findings only in its later stages. We describe a series of patients in whom the diagnosis is supported by changes in the medial antebrachial cutaneous (MAC) nerve at or before the development of these typical EMG findings in median and ulnar nerves.

The protein composition of gingival crevicular fluid sampled from male adolescents with no destructive periodontitis: baseline data of a longitudinal study

Gingival crevicular fluid (GCF) is a promising source for markers of destructive periodontal diseases activity. As the initial stage of a longitudinal study into the characterization of disease markers, GCF sampled from 104 sites in 74 adolescents was examined via sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS/PAGE). In this population, which had varying degrees of gingivitis but little evidence of destructive periodontitis, there was a highly homologous GCF protein profile. The plasma components, albumin, transferrin and IgG, were major constituents of all samples. In addition, a second group of non-plasma derived proteins, with molecular weights 37 kDa, 47 kDa, 57 kDa and 59 kDa, was also commonly detected. The high frequency of occurrence of these components suggests that they may represent products of normal turnover of the periodontal tissues. Analysis of GCF sampled from patients with progressing destructive disease revealed a different SDS/PAGE profile particularly with respect to proteins of non-plasma origin. It is anticipated that the major metabolic changes which accompany the destruction of the tissues during future disease episodes in the adolescent study population will be discernible as alterations to the GCF protein profile.

The kinetics of transport of lactate and pyruvate into isolated cardiac myocytes from guinea pig. Kinetic evidence for the presence of a carrier distinct from that in erythrocytes and hepatocytes

1. Time courses for the uptake of L-lactate, D-lactate and pyruvate into isolated cardiac ventricular myocytes from guinea pig were determined at 11 degrees C or 0 degrees C (for pyruvate) in a citrate-based buffer by using a silicone-oil-filtration technique. These conditions enabled initial rates of transport to be measured without interference from metabolism of the substrates. 2. At a concentration of 0.5 mM, transport of all these substrates was inhibited by approx. 90% by 5 mM-alpha-cyano-4-hydroxycinnamate; at 10 mM-L-lactate a considerable portion of transport could not be inhibited. 3. Initial rates of L-lactate and pyruvate uptake in the presence of 5 mM-alpha-cyano-4-hydroxycinnamate were linearly related to the concentration of the monocarboxylate and probably represented diffusion of the free acid. The inhibitor-sensitive component of uptake obeyed Michaelis-Menten kinetics, with Km values for L-lactate and pyruvate of 2.3 and 0.066 mM respectively. 4. Pyruvate and D-lactate inhibited the transport of L-lactate, with Ki values (competitive) of 0.077 and 6.6 mM respectively; the Ki for pyruvate was very similar to its Km for transport. The Ki for alpha-cyano-4-hydroxycinnamate as a non-competitive inhibitor was 0.042 mM. 5. These results indicate that L-lactate, D-lactate and pyruvate share a common carrier in guinea-pig cardiac myocytes; the low stereoselectivity for L-lactate over D-lactate and the high affinity for pyruvate distinguish it from the carrier in erythrocytes and hepatocytes. The metabolic roles for this novel carrier in heart are discussed.

A method for the refinement of data arising from electrophoresis of biological fluids

Gingival crevicular fluid (GCF) is being analyzed by sodium dodecyl sulfate/polyacrylamide gel electrophoresis (SDS/PAGE) in our laboratory. We wish to characterize the major protein species in GCF and to investigate their association with the progression of disease. Laser densitometry of SDS/PAGE provides estimates of log molecular weight (LMW) and relative abundance for each band in each sample. Our aim was to develop a method for the refinement of these data into clusters which could be treated as distinct protein species, whose relation to disease progression could be assessed. A reproducibility study showed that the estimated LMW would fall within 3% of the true LMW 95% of the time. The method clusters the estimated LMWs of each band in each sample so that clusters form at LMWs which occurred frequently. The data from each band in each sample are thus refined into cluster number and relative abundance. Application of the technique to data from the reproducibility study showed that clusters formed around the individual components in the mixture, with little misclassification. The technique was then applied to two data sets: from SDS/PAGE of 104 GCF samples from 74 adolescents without progressive periodontal disease, and from 2 patients suffering from advanced progressive disease. The clusters appeared accurately to reflect the appearance of the gels, and clear differences were observed between the two data sets. The method will enable changes in the composition of biological fluids to be associated with external factors such as disease status and should be widely applicable.

The total protein concentration of gingival crevicular fluid. Variation with sampling time and gingival inflammation

The total protein concentration of gingival crevicular fluid (GCF), sampled repeatedly over a 10-min period with the minimum of physical irritation to the sulcus, was evaluated in a group of 32 healthy adolescents. The mean concentration of the 1st sample was comparable to that of normal tissue fluids and lymph, irrespective of the state of inflammation of the sample site. However, during repeated sampling, the values rose to resemble serum protein levels, except at those sites with no clinically detectable inflammation. Gel electrophoretic analysis confirmed the increasing proportion of serum-derived molecules in the more proteinaceous GCF samples. The results demonstrate the extreme sensitivity of the gingival vasculature to GCF sampling and consequently the need for accurate standardisation of GCF collection protocols. This will apply particularly when compositional data is to be normalised with respect to the total protein content or when the levels of a serum constituent are being examined.