Molecular and Genetic Characterization of Natural Variants of HIV-1 Nef Gene from North India and its Functional Implication in Down-Regulation of MHC-I and CD-4

BACKGROUND

HIV-1 Nef is an important accessory protein with multiple effector functions. Genetic studies of the HIV-1 Nef gene show extensive genetic diversity and the functional studies have been carried out mostly with Nef derived from regions dominated by subtype B (North America & Europe).

OBJECTIVE

This study was carried out to characterize genetic variations of the Nef gene from HIV-1 infected individuals from North India and to find out their functional implications.

METHODS

The unique representative variants were sub-cloned in a eukaryotic expression vector and further characterized with respect to their ability to downregulate cell surface expression of CD4 and MHC-1 molecules.

RESULTS

The phylogenetic analysis of Nef variants revealed sequence similarity with either consensus subtype B or B/C recombinants. Boot scan analysis of some of our variants showed homology to B/C recombinant and some to wild type Nef B. Extensive variations were observed in most of the variants. The dN/dS ratio revealed 80% purifying selection and 20% diversifying selection implying the importance of mutations in Nef variants. Intracellular stability of Nef variants differed greatly when compared with wild type Nef B and C. There were some variants that possessed mutations in the functional domains of Nef and responsible for its differential CD4 and MHC-1 downregulation activity.

CONCLUSION

We observed enhanced biological activities in some of the variants, perhaps arising from amino acid substitutions in their functional domains. The CD4 and MHC-1 down-regulation activity of Nef is likely to confer immense survival advantage allowing the most rare genotype in a population to become the most abundant after a single selection event.

Preparation and Characterization of Nb-1Zr-0.1C Alloy Suitable for Liquid Metal Coolant Channels of High Temperature Reactors

A novel process comprising of aluminothermic coreduction of mixed oxides followed by arc and electron beam melt refining was developed for preparation of Nb-1Zr-0.1C alloy. The parameters of the process were optimized by considering the thermodynamic (heat) and mass balance phenomenon. The ingots of the homogenized alloy produced after electron beam melt consolidation were further extruded into tubes. The alloy was vacuum annealed at 1350–1800 °C to study the stability of Nb2C and Nb(Zr)C carbide precipitates in the microstructure. Compression creep tests conducted at 900 and 1000 °C revealed a stress exponent value of 2 and activation energy of 508 kJ/mol. NbSi2-based coatings were developed on the Nb-1Zr-0.1C alloy tubes using pack siliconizing process. The coated alloy was tested for oxidation at 1250 °C, and corrosion in liquid lead-bismuth eutectic (LBE) alloy at 875 °C for prolonged duration. The silicide-coated alloy showed superior oxidation and LBE corrosion resistance at high temperatures. The alloy was found to be a promising material for coolant channels of high temperature reactors.

Neurofilament results for the phase II neuroprotection study of phenytoin in optic neuritis

BACKGROUND

A randomized trial of phenytoin in acute optic neuritis (ON) demonstrated a 30% reduction in retinal nerve fiber layer (RNFL) loss with phenytoin versus placebo. Here we present the corresponding serum neurofilament analyses.

METHODS

Eighty-six acute ON cases were randomized to receive phenytoin (4-6 mg/kg/day) or placebo for 3 months, and followed up for 6 months. Serum was collected at baseline, 3 and 6 months for analysis of neurofilament heavy chain (NfH) and neurofilament light chain (NfL).

RESULTS

Sixty-four patients had blood sampling. Of these, 58 and 56 were available at 3 months, and 55 and 54 were available at 6 months for NfH and NfL, respectively. There was no significant correlation between serum NfH and NfL at the time points tested. For NfH, the difference in mean placebo - phenytoin was -44 pg/ml at 3 months (P = 0.019) and -27 pg/ml at 6 months (P = 0.234). For NfL, the difference was 1.4 pg/ml at 3 months (P = 0.726) and -1.6 pg/ml at 6 months (P = 0.766).

CONCLUSIONS

At 3 months, there was a reduction in NfH, but not NFL, in the phenytoin versus placebo group, while differences at 6 months were not statistically significant. This suggests a potential neuroprotective role for phenytoin in acute ON, with the lower NfH at 3 months, when levels secondary to degeneration of the anterior visual pathway are still elevated, but not at 6 months, when levels have normalized.

Serum neurofilament light as a biomarker in progressive multiple sclerosis

There is an unmet need in multiple sclerosis (MS) therapy for treatments to stop progressive disability. The development of treatments may be accelerated if novel biomarkers are developed to overcome the limitations of traditional imaging outcomes revealed in early phase trials. In January 2019, the International Progressive MS Alliance convened a standing expert panel to consider potential tissue fluid biomarkers in MS in general and in progressive MS specifically. The panel focused their attention on neurofilament light chain (NfL) in serum or plasma, examining data from both relapsing and progressive MS. Here, we report the initial conclusions of the panel and its recommendations for further research. Serum NfL (sNfL) is a plausible marker of neurodegeneration that can be measured accurately, sensitively, and reproducibly, but standard procedures for sample processing and analysis should be established. Findings from relapsing and progressive cohorts concur and indicate that sNfL concentrations correlate with imaging and disability measures, predict the future course of the disease, and can predict response to treatment. Importantly, disease activity from active inflammation (i.e., new T2 and gadolinium-enhancing lesions) is a large contributor to sNfL, so teasing apart disease activity from the disease progression that drives insidious disability progression in progressive MS will be challenging. More data are required on the effects of age and comorbidities, as well as the relative contributions of inflammatory activity and other disease processes. The International Progressive MS Alliance is well positioned to advance these initiatives by connecting and supporting relevant stakeholders in progressive MS.

Effect of prophylactic granulocyte-colony stimulating factor (G-CSF) on acute hematological toxicity in medulloblastoma patients during craniospinal irradiation (CSI)

OBJECTIVES

Haematological toxicity and treatment breaks are common during cranio-spinal irradiation (CSI) due to irradiation of large volume of bone marrow. We conducted this study to see the effect of prophylactic granulocyte colony stimulating factor (GCSF) in reducing treatment breaks.

PATIENTS AND METHODS

The study was conducted over a period of 15 months from August 2017 to November 2018. Histopathologically proven Medulloblastoma patients received prophylactic GCSF during CSI. Acute hematological toxicities and treatment breaks were noted and effect of age and pretreatment blood counts were analyzed by SPSS (Statistical Package for Social Sciences) version 23.

RESULTS

A total of 28 patients were included in the study. During CSI, hematological toxicity leading to treatment breaks was observed in 11 (39.3 %) patients, of which grade 3 and 2 toxicities were seen in ten and one patients respectively. Younger age (<10 years) at diagnosis was significantly associated with the development of hematological toxicity (p = 0.028, Chi-Square). No correlation was found with pre-treatment blood counts.

CONCLUSION

Prophylactic use of GCSF may be effective in preventing radiation induced hematological toxicity and treatment breaks.

Factors Associated With Cerebral Edema at Admission in Indian Children with Diabetic Ketoacidosis

OBJECTIVE

To evaluate the time course and predictors of cerebral edema in diabetic ketoacidosis (DKA).

METHODS

Review of hospital records of 107 episodes of DKA between January 2013 to March 2019.

RESULTS

Cerebral edema was identified in 26 (24.3%; 22 at presentation and 4 during treatment). Cerebral edema at presentation was associated with lower (<10 mmHg) arterial carbon dioxide (OR 3.6, 95% CI 1.0,12.7; P=0.04), prior fluid treatment (OR 4.7, 95% CI 1.8,12.7; P=0.001) and new onset diabetes (OR 3.5, 95% CI 1.1,11.1; P=0.03). Prior fluid was the only significant predictor on multivariate analysis (P=0.013). Cerebral edema resulted in a longer ICU stay [4.1 (2.3) vs 1.8 (0.9) d; P<0.001].

CONCLUSIONS

Cerebral edema at admission is common in Indian children with DKA and should be suspected with severe metabolic acidosis and inappropriate prior fluid treatment.

FDG-PET response and outcome from anti-PD-1 therapy in metastatic melanoma

Background

Immune checkpoint inhibitor therapy has resulted in impressive and durable clinical activity for many cancers including melanoma; however, there remain few reliable predictors for long-term response. This study investigated whether [18F]2-fluoro-2-deoxy-D-glucose (FDG-PET) imaging may better predict long-term outcomes compared with standard computed tomography (CT) response criteria.

Patients and methods

Retrospective analysis of metastatic melanoma patients treated with anti-PD-1-based immunotherapy with baseline and 1-year FDG-PET and CT imaging at Melanoma Institute Australia. One-year response was determined using RECIST for CT and EORTC criteria for PET, coded as complete response (CR or CMR), partial response (PR or PMR), stable disease (SD or SMD) or progressive disease (PD or PMD). Progression-free survival (PFS) was determined from the 1-year landmark.

Results

Patients (n = 104) were evaluated with median follow-up 30.1 months and 98% remain alive. Most received anti-PD-1 as monotherapy (67%) or combined with ipilimumab (31%). At 1 year, 28% had CR, 66% had PR and 6% had SD on CT, while 75% had CMR, 16% PMR and 9% SMD/PMD on PET. CMR was observed in 68% of patients with PR on CT. RECIST PFS post 1-year landmark was similar in patients with CR versus PR/SD, but improved in patients with CMR versus non-CMR {median not reached [NR] versus 12.8 month; hazard ratio [HR] 0.06 [95% confidence interval (CI) 0.02-0.23]; P < 0.01}. In patients with PR on CT, PFS was improved in patients with PR + CMR versus PR + non-CMR (median NR versus 12.8 months; HR 0.07 [95% CI 0.02-0.27]; P < 0.01). In the 78 CMR patients, 78% had discontinued treatment and 96% had ongoing response.

Conclusions

Whilst only a small proportion of patients have a CR at 1 year, most patients with a PR have CMR on PET. Almost all patients with CMR at 1 year have ongoing response to therapy thereafter. PET may have utility in predicting long-term benefit and help guide discontinuation of therapy.

P14.06 Phase II randomized trial of short course hypofractionated radiotherapy with or without temozolomide in elderly patients with Glioblastoma

BACKGROUND

Glioblastoma (GBM) is the most aggressive primary brain tumor. Although treatment advances and introduction of temozolomide has improved the outcome in young patients, it is still a concern in elderly patients. Elderly population is often excluded from the trials, thus established treatment guidelines are not available. Trials have shown that short course hypofractionated radiotherapy (HRT) is equally effective in terms of overall survival (OS) and progression free survival (PFS) as compared to standard RT in elderly population. While the benefit of adding Temozolomide (TMZ) to standard dose radiotherapy is well established, there is lack of evidence that addition of TMZ to HRT improves survival in elderly patients.We conducted this study to see if addition of temozolomide to HRT improves OS, PFS and quality of life (QOL) in elderly GBM patients.

MATERIAL AND METHODS

The study was conducted over a period of 21 months from January 2017 to September 2018. Histologically proven 70 newly diagnosed Glioblastoma patients (age>60 years) were enrolled and randomized into two arms (Arm I- HRT alone, Arm II- HRT and TMZ) using computer generated randomization table (1:1 ratio). The radiotherapy dose in both arms was same and consisted of a dose of 25Gy in 5 daily fractions over 1 week. In addition, arm II patients received daily concurrent TMZ 75mg/m2 1 hour prior to RT followed by adjuvant TMZ 175mg/m2 from Day1-5 for 6 cycles (q 4weeks), started after a month of RT completion. Quality of life score and global health status was assessed in both arms at baseline, 1, 3, 6 and 9 months after the treatment using QOL questionnaire EORTC QLQ-C 30 and QLQ-BN20. Data entry was done in Microsoft Excel 2016 and analysis was done in SPSS version 18. Kaplan Meier survival analysis was done for OS and PFS. To see the trend of time related observations at different point of time repeated ANOVA was used. A p value of <0.05 was taken significant.

RESULTS

The median OS in arm I and II was 121 (range 40–360 days) and 146 (range 40–450 days) days respectively (P=0.146). The median PFS in arm 1 and arm 2 were 77 (range 30–300 days) and 109.50 (range 30–300) days respectively (p-0.028). On further analysis, the prognostic factors were type of surgery (Median PFS 159 days in gross total excision and 129 days in subtotal excision or biopsy, p-0.03) and KPS (0.04). QOL score for symptom and functional domain was comparable in both arms. However score of nausea and vomiting was higher during concurrent chemoradiotherapy. A non significant improvement in QLQ BN 20 score was observed at 9 months in arm I.

CONCLUSION

Addition of Temozolomide to HRT is a compelling option in elderly Glioblastoma patients as it significantly improves the PFS and a non significant improvement in OS without compromising quality of life.

Etiology and characteristics of pediatric urethral strictures in a developing country in the 21st century

BACKGROUND

Urethral stricture disease in children is not uncommon as assumed; however, most of the information about the etiology, features, and natural history of pediatric strictures is extrapolations from adult series as the literature on this common entity is sparse, and most of the studies are small series.

OBJECTIVE

The current etiology and clinical features of urethral stricture disease in the pediatric population in the developing world were determined.

MATERIALS AND METHODS

The data of children with urethral stricture disease, who had undergone treatment in the tertiary center from 2001 to 2017, were retrospectively analyzed. After excluding girls, the database was analyzed for clinical presentation, possible causes of stricture, site and number of strictures, and length of stricture and for previous interventions. Subanalysis was performed for stricture etiology by patient age, stricture length, site, previous treatments, and presentation with paraurethral abscess.

RESULTS

A total of 195 boys with strictures were identified. The common causes of pediatric urethral stricture were traumatic (36.9%), iatrogenic (31.8%), and idiopathic (28.7%). The anterior urethra was the location of the stricture in 141 patients (72.3%). Iatrogenic causes (due to catheterization, hypospadias repair, and valve fulguration) accounted for the majority of anterior urethral strictures (61/141 or 43.2%). Younger children had a tendency to have an iatrogenic and idiopathic cause for strictures, whereas older children had a traumatic etiology; 18.6% of strictures in children younger than 10 years were secondary to trauma, whereas 44.9% of the strictures in patients older than 10 years were traumatic in origin. Trauma was the major cause of posterior urethral strictures (53/54 or 98.1%) and was always associated with pelvic fracture. Strictures due to lichen sclerosus or infectious cause were rare (5 patients or 2.6%). The length of strictures was longer in pan anterior urethral strictures (mean: 82.0 mm) than that of those due to lichen sclerosus (mean: 42.5 mm) and in patients who had undergone previous treatment (mean: 28.7 mm).

CONCLUSION

Iatrogenic causes such as catheterization and hypospadias repair account for the majority of anterior urethral stricture disease in the pediatric population, especially the younger age-group. However, as the child grows, there is a gradual preponderance of traumatic urethral strictures, including posterior urethral strictures.

Introducing FDG PET/CT-guided chemoradiotherapy for stage III NSCLC in low- and middle-income countries: preliminary results from the IAEA PERTAIN trial

Purpose

Patients with stage III non-small-cell lung cancer (NSCLC) treated with chemoradiotherapy (CRT) in low- and middle-income countries (LMIC) continue to have a poor prognosis. It is known that FDG PET/CT improves staging, treatment selection and target volume delineation (TVD), and although its use has grown rapidly, it is still not widely available in LMIC. CRT is often used as sequential treatment, but is known to be more effective when given concurrently. The aim of the PERTAIN study was to assess the impact of introducing FDG PET/CT-guided concurrent CRT, supported by training and quality control (QC), on the overall survival (OS) and progression-free survival (PFS) of patients with stage III NSCLC.

Methods

The study included patients with stage III NSCLC from nine medical centres in seven countries. A retrospective cohort was managed according to local practices between January 2010 and July 2014, which involved only optional diagnostic FDG PET/CT for staging (not for TVD), followed by sequential or concurrent CRT. A prospective cohort between August 2015 and October 2018 was treated according to the study protocol including FDG PET/CT in treatment position for staging and multimodal TVD followed by concurrent CRT by specialists trained in protocol-specific TVD and with TVD QC. Kaplan–Meier analysis was used to assess OS and PFS in the retrospective and prospective cohorts.

Results

Guidelines for FDG PET/CT image acquisition and TVD were developed and published. All specialists involved in the PERTAIN study received training between June 2014 and May 2016. The PET/CT scanners used received EARL accreditation. In November 2018 a planned interim analysis was performed including 230 patients in the retrospective cohort with a median follow-up of 14 months and 128 patients in the prospective cohort, of whom 69 had a follow-up of at least 1 year. Using the Kaplan–Meier method, OS was significantly longer in the prospective cohort than in the retrospective cohort (23 vs. 14 months, p = 0.012). In addition, median PFS was significantly longer in the prospective cohort than in the retrospective cohort (17 vs. 11 months, p = 0.012).

Conclusion

In the PERTAIN study, the preliminary results indicate that introducing FDG PET/CT-guided concurrent CRT for patients with stage III NSCLC in LMIC resulted in a significant improvement in OS and PFS. The final study results based on complete data are expected in 2020.

Electronic supplementary material

The online version of this article (10.1007/s00259-019-04421-5) contains supplementary material, which is available to authorized users.

Radiotherapy treatment of human inflammatory diseases and conditions: Optimal dose

During the early part of the past century, hundreds of clinical studies involving more than 37,000 patients were conducted that showed radiotherapy (RT) to be a successful and safe alternative to drug therapy for the treatment of many diverse inflammatory conditions and diseases (e.g. tendonitis, bursitis, arthritis, and serious inflammatory lung conditions). Data from these studies were collected and analyzed with the intent of estimating an optimal dosing range for RT that would induce an efficacious treatment response. RT was reported to be frequently effective after only a single treatment, with a rapid (within 24 h) and often long-lasting (from months to years) relief from symptoms. Over a two-decade span from the 1920s to the 1940s, the therapeutic responses to a single RT treatment consistently improved as the dosing for multiple ailments decreased over time to between 30 roentgen (r) and 100 r. These findings are significant and in agreement with a number of contemporary reports from Germany where RT has been commonly and successfully employed in treating ailments with an inflammatory origin. A proposed mechanism by which RT mitigates inflammation and facilitates healing is via the polarization of macrophages to an anti-inflammatory or M2 phenotype.

Outcomes of Primary Arteriovenous Fistula for Hemodialysis in Elderly Patients (>65 Years) with End Stage Renal Disease: A Study on Indian Population

Introduction:

The outcome of arteriovenous fistula (AVF) for hemodialysis (HD) in elderly population remains an issue. The aim of our study was to evaluate the outcomes of arteriovenous fistulas created at our institute in patients older than 65 years.

Methods:

All chronic HD patients with age >65 years who had an AVF created between January 1, 2010 and January 1, 2017 were included retrospectively. Baseline demographic information including age, gender, etiology of renal failure and comorbidities were recorded. Access characteristics including access type and anatomic location were recorded. The end point of study was primary and secondary patency. Minimum follow up period of study was 1 year.

Results:

A total of 422 AVF were created within the study period. The mean age was 69.3 years. The anatomical site of AVF creation was radiocephalic (RCF) in 74.8% (n = 316), brachiocephalic (BCF) in 18.9% (n = 80) and brachiobasilic (BBF) in 6.1% (n = 26). At one year after creation, cumulative survival of the AVF was 64.7%. At 36 months the primary and secondary patency of RCF, BCF and BBF was 43.6%, 58.6%, 42.6% and 47.3%, 62.5%, 56.9% respectively. The overall median survival did not differ between RCF and BBF fistulas. However, when both were compared with BCF (median survival 1034 days), BBF (median survival 741 days) and RCF (median survival 592 days) had significantly poorer survival (P = 0.004). The most common reason for access failure was thrombosis (28.4%) followed by failure to mature (9%) and aneurysm related complications (9%).

Conclusions:

Age should not be a limiting factor when choosing AVF as the preferred HD access. Brachiocephalic AVF has better primary and secondary patency with higher overall median survival. However RCF also provides reasonably good survival rates with acceptable complications in elderly population. Thrombosis and fistulas that fail to mature present as a primary concern to patients in elderly population, and demand further study.

Treatment data and technical process challenges for practical big data efforts in radiation oncology

The term Big Data has come to encompass a number of concepts and uses within medicine. This paper lays out the relevance and application of large collections of data in the radiation oncology community. We describe the potential importance and uses in clinical practice. The important concepts are then described and how they have been or could be implemented are discussed. Impediments to progress in the collection and use of sufficient quantities of data are also described. Finally, recommendations for how the community can move forward to achieve the potential of big data in radiation oncology are provided.

Effect of natalizumab on disease progression in secondary progressive multiple sclerosis (ASCEND): a phase 3, randomised, double-blind, placebo-controlled trial with an open-label extension

BACKGROUND

Although several disease-modifying treatments are available for relapsing multiple sclerosis, treatment effects have been more modest in progressive multiple sclerosis and have been observed particularly in actively relapsing subgroups or those with lesion activity on imaging. We sought to assess whether natalizumab slows disease progression in secondary progressive multiple sclerosis, independent of relapses.

METHODS

ASCEND was a phase 3, randomised, double-blind, placebo-controlled trial (part 1) with an optional 2 year open-label extension (part 2). Enrolled patients aged 18-58 years were natalizumab-naive and had secondary progressive multiple sclerosis for 2 years or more, disability progression unrelated to relapses in the previous year, and Expanded Disability Status Scale (EDSS) scores of 3·0-6·5. In part 1, patients from 163 sites in 17 countries were randomly assigned (1:1) to receive 300 mg intravenous natalizumab or placebo every 4 weeks for 2 years. Patients were stratified by site and by EDSS score (3·0-5·5 vs 6·0-6·5). Patients completing part 1 could enrol in part 2, in which all patients received natalizumab every 4 weeks until the end of the study. Throughout both parts, patients and staff were masked to the treatment received in part 1. The primary outcome in part 1 was the proportion of patients with sustained disability progression, assessed by one or more of three measures: the EDSS, Timed 25-Foot Walk (T25FW), and 9-Hole Peg Test (9HPT). The primary outcome in part 2 was the incidence of adverse events and serious adverse events. Efficacy and safety analyses were done in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, number NCT01416181.

FINDINGS

Between Sept 13, 2011, and July 16, 2015, 889 patients were randomly assigned (n=440 to the natalizumab group, n=449 to the placebo group). In part 1, 195 (44%) of 439 natalizumab-treated patients and 214 (48%) of 448 placebo-treated patients had confirmed disability progression (odds ratio [OR] 0·86; 95% CI 0·66-1·13; p=0·287). No treatment effect was observed on the EDSS (OR 1·06, 95% CI 0·74-1·53; nominal p=0·753) or the T25FW (0·98, 0·74-1·30; nominal p=0·914) components of the primary outcome. However, natalizumab treatment reduced 9HPT progression (OR 0·56, 95% CI 0·40-0·80; nominal p=0·001). In part 1, 100 (22%) placebo-treated and 90 (20%) natalizumab-treated patients had serious adverse events. In part 2, 291 natalizumab-continuing patients and 274 natalizumab-naive patients received natalizumab (median follow-up 160 weeks [range 108-221]). Serious adverse events occurred in 39 (13%) patients continuing natalizumab and in 24 (9%) patients initiating natalizumab. Two deaths occurred in part 1, neither of which was considered related to study treatment. No progressive multifocal leukoencephalopathy occurred.

INTERPRETATION

Natalizumab treatment for secondary progressive multiple sclerosis did not reduce progression on the primary multicomponent disability endpoint in part 1, but it did reduce progression on its upper-limb component. Longer-term trials are needed to assess whether treatment of secondary progressive multiple sclerosis might produce benefits on additional disability components.

FUNDING

Biogen.

Role of Preoperative Duplex Ultrasonography to Predict Functional Maturation of Wrist Radiocephalic Arteriovenous Fistula: A Study on Indian Population

Radiocephalic arteriovenous fistula (RCAVF) is the first choice for native arteriovenous fistula (AVF). Preoperative vessel assessment with ultrasonography (USG) has been reported to enhance the outcome of native AVF, but data regarding its predictive value for functional maturation of RCAVF are scanty. We aimed to determine the role of preoperative duplex USG (DUS) for prediction of functional maturity of radiocephalic fistula in the wrist. The data from 173 patients were analyzed prospectively. The estimated duplex variable included size, patency, and continuity of cephalic vein and size, peak systolic velocity, and wall calcifications in radial artery at the wrist. The subjects underwent RCAVF creation and were reviewed 6-8 weeks post procedure for adequacy of maturation. Doppler variables between successful and failed maturation groups were compared. Successful functional fistula maturation was noted in 138 (80.9%) patients. Values of radial artery diameter, cephalic vein diameter, and peak systolic velocity were >2 mm, 2.2 mm, and 32.8 cm/s, respectively, for successful maturation of RCAVF in more than 90% of cases. Vascular calcifications were detected preoperatively in 15 diabetic patients and 9 (60%) of them had fistula failure. Preoperative DUS can provide a good prediction on functional maturation of RCAVF. Vascular calcifications were associated with high risk of maturation failure in diabetics.

Melanoma patient imaging in the era of effective systemic therapies

Imaging plays a critical role in the current multi-disciplinary management of patients with melanoma. It is used for primary disease staging, surgical planning, and surveillance in high-risk patients, and for monitoring the effects of systemic or loco-regional therapies. Several different imaging modalities have been utilised in the past. Contemporary imaging practises vary geographically depending on clinical guidelines, physician preferences, availability and cost. Targeted therapies and immunotherapies have revolutionised the treatment of patients with metastatic melanoma over the last few years. With this have come new patterns of disease that were not observed after conventional therapies, and new criteria to assess therapeutic responses. In this article we review the role of imaging for patients with melanoma in the era of effective systemic therapies and discuss likely future developments.

Validity of low-contrast letter acuity as a visual performance outcome measure for multiple sclerosis

Low-contrast letter acuity (LCLA) has emerged as the leading outcome measure to assess visual disability in multiple sclerosis (MS) research. As visual dysfunction is one of the most common manifestations of MS, sensitive visual outcome measures are important in examining the effect of treatment. Low-contrast acuity captures visual loss not seen in high-contrast visual acuity (HCVA) measurements. These issues are addressed by the MS Outcome Assessments Consortium (MSOAC), including representatives from advocacy organizations, Food and Drug Administration (FDA), European Medicines Agency (EMA), National Institute of Neurological Disorders and Stroke (NINDS), academic institutions, and industry partners along with persons living with MS. MSOAC goals are acceptance and qualification by regulators of performance outcomes that are highly reliable and valid, practical, cost-effective, and meaningful to persons with MS. A critical step is elucidation of clinically relevant benchmarks, well-defined degrees of disability, and gradients of change that are clinically meaningful. This review shows that MS and disease-free controls have similar median HCVA, while MS patients have significantly lower LCLA. Deficits in LCLA and vision-specific quality of life are found many years after an episode of acute optic neuritis, even when HCVA has recovered. Studies reveal correlations between LCLA and the Expanded Disability Status Score (EDSS), Multiple Sclerosis Functional Composite (MSFC), retinal nerve fiber layer (RNFL) and ganglion cell layer plus inner plexiform layer (GCL + IPL) thickness on optical coherence tomography (OCT), brain magnetic resonance imaging (MRI), visual evoked potential (VEP), electroretinogram (ERG), pupillary function, and King-Devick testing. This review also concludes that a 7-point change in LCLA is clinically meaningful. The overall goal of this review is to describe and characterize the LCLA metric for research and clinical use among persons with MS.

Normal-appearing grey and white matter T1 abnormality in early relapsing–remitting multiple sclerosis: a longitudinal study

Objective

To investigate the presence and evolution of T1 relaxation time abnormalities in normal-appearing white matter (NAWM) and grey matter (GM), early in the course of relapsing–remitting multiple sclerosis (MS).

Methods

Twenty-three patients with early relapsing–remitting MS and 14 healthy controls were imaged six monthly for up to three years. Mean follow-up was 26 months for MS patients and 24 months for controls. Dual-echo fast-spin echo and gradient-echo proton-density and T1-weighted data sets (permitting the calculation of a T1 map) were acquired in all subjects. GM and NAWM T1 histograms were produced and a hierarchical regression model was used to investigate changes in T1 over time.

Results

At baseline, significant patient-control differences were seen, both in NAWM (P = 0.001) and in GM (P = 0.01). At follow-up, there was no evidence for a serial change in either mean T1 or peak-location for either NAWM or GM. There was weak evidence for a decline in patient NAWM peak-height and also evidence for a decline in control GM peak-height.

Conclusion

There are significant and persistent abnormalities of NAWM and GM T1 in early relapsing-remitting MS. Further studies should address whether such T1 measures have a role in prognosis or therapeutic monitoring. Multiple Sclerosis 2007; 13:169–177. http://msj.sagepub.com

A multi-time-point modality-agnostic patch-based method for lesion filling in multiple sclerosis

Multiple sclerosis lesions influence the process of image analysis, leading to tissue segmentation problems and biased morphometric estimates. Existing techniques try to reduce this bias by filling all lesions as normal-appearing white matter on T1-weighted images, considering each time-point separately. However, due to lesion segmentation errors and the presence of structures adjacent to the lesions, such as the ventricles and deep grey matter nuclei, filling all lesions with white matter-like intensities introduces errors and artefacts. In this paper, we present a novel lesion filling strategy inspired by in-painting techniques used in computer graphics applications for image completion. The proposed technique uses a five-dimensional (5D), patch-based (multi-modality and multi-time-point), Non-Local Means algorithm that fills lesions with the most plausible texture. We demonstrate that this strategy introduces less bias, fewer artefacts and spurious edges than the current, publicly available techniques. The proposed method is modality-agnostic and can be applied to multiple time-points simultaneously. In addition, it preserves anatomical structures and signal-to-noise characteristics even when the lesions are neighbouring grey matter or cerebrospinal fluid, and avoids excess of blurring or rasterisation due to the choice of the segmentation plane, shape of the lesions, and their size and/or location.

REVIEW ■ : Axonal Hyperexcitability: Mechanisms and Role in Symptom Production in Demyelinating Diseases

Some of the symptoms associated with demyelinating disorders are believed to originate from spurious impulses arising ectopically in axons at the site of demyelination. This review describes such "positive" symptoms and the patterns of impulses that may be associated with them, including continuous trains of impulses, as well as spontaneous and triggered impulse bursts. The mechanisms underlying the generation of such trains by individual axons are described, including the roles of sodium and potassium currents, the composition of the extracellular fluid, impulse "reflection" at demyelinated sites, and stretch-sensitive ion channels. The contribution of ephaptic transmission to symptom production and its potential role in the generation of ectopic impulses are discussed. The factors involved in the generation of massed discharges are also examined as a basis for certain paroxysmal clinical phenomena. NEUROSCIENTIST 3:237-246, 1997