An intramolecular cross-talk in D29 mycobacteriophage endolysin governs the lytic cycle and phage-host population dynamics

D29 mycobacteriophage encodes LysA endolysin, which mediates mycobacterial host cell lysis by targeting its peptidoglycan layer, thus projecting itself as a potential therapeutic. However, the regulatory mechanism of LysA during the phage lytic cycle remains ill defined. Here, we show that during D29 lytic cycle, structural and functional regulation of LysA not only orchestrates host cell lysis but also is critical for maintaining phage-host population dynamics by governing various phases of lytic cycle. We report that LysA exists in two conformations, of which only one is active, and the protein undergoes a host peptidoglycan-dependent conformational switch to become active for carrying out endogenous host cell lysis. D29 maintains a pool of inactive LysA, allowing complete assembly of phage progeny, thus helping avoid premature host lysis. In addition, we show that the switch reverses after lysis, thus preventing exogenous targeting of bystanders, which otherwise negatively affects phage propagation in the environment.

Pseudomonas Phage ZCPS1 Endolysin as a Potential Therapeutic Agent

The challenge of antibiotic resistance has gained much attention in recent years due to the rapid emergence of resistant bacteria infecting humans and risking industries. Thus, alternatives to antibiotics are being actively searched for. In this regard, bacteriophages and their enzymes, such as endolysins, are a very attractive alternative. Endolysins are the lytic enzymes, which are produced during the late phase of the lytic bacteriophage replication cycle to target the bacterial cell walls for progeny release. Here, we cloned, expressed, and purified LysZC1 endolysin from Pseudomonas phage ZCPS1. The structural alignment, molecular dynamic simulation, and CD studies suggested LysZC1 to be majorly helical, which is highly similar to various phage-encoded lysozymes with glycoside hydrolase activity. Our endpoint turbidity reduction assay displayed the lytic activity against various Gram-positive and Gram-negative pathogens. Although in synergism with EDTA, LysZC1 demonstrated significant activity against Gram-negative pathogens, it demonstrated the highest activity against Bacillus cereus. Moreover, LysZC1 was able to reduce the numbers of logarithmic-phase B. cereus by more than 2 log₁₀ CFU/mL in 1 h and also acted on the stationary-phase culture. Remarkably, LysZC1 presented exceptional thermal stability, pH tolerance, and storage conditions, as it maintained the antibacterial activity against its host after nearly one year of storage at 4 °C and after being heated at temperatures as high as 100 °C for 10 min. Our data suggest that LysZC1 is a potential candidate as a therapeutic agent against bacterial infection and an antibacterial bio-control tool in food preservation technology.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

396 Rotator Cuff Assessment Following Traumatic Anterior Shoulder Dislocation

Aim

Glenohumeral joint dislocation is the most common traumatic joint dislocation with a high recurrence rate correlating with age at first dislocation. There is an associated increased incidence in concurrent rotator cuff tears with increasing age affecting 40% aged 40–60. Patient care was assessed against BESS/BOA standard: These patients should have rotator cuff assessment and those aged 40–60 should undergo routine MRI/Ultrasound imaging.

Method

All patients admitted to the emergency departments of the 3 Lanarkshire hospitals undergoing first time traumatic anterior dislocation of the shoulder in February 2021 were included. This was the third cycle of this audit. Previous interventions were presentation at a CPD meeting after cycle one and an NHS Lanarkshire regional meeting after cycle two.

Results

Cycle one (2018)-14 patients. 3/14 underwent rotator cuff assessment. 5/14 aged 40–60. 1/5 underwent rotator cuff imaging.

Cycle two (2020)-11 patients. 0/9 underwent rotator cuff assessment (Two excluded as managed operatively). 4/11 aged 40–60. 0/4 underwent rotator cuff imaging.

Cycle three (2021)-13 patients. 3/11 underwent rotator cuff assessment (Two excluded as managed operatively). 3/13 aged 40–60. 0/3 underwent rotator cuff imaging.

Conclusions

Although a slight improvement has been made over the 3 cycles with rotator cuff assessment the BOA standard is not being met. There has been no improvement in the additional imaging required in traumatic anterior shoulder dislocations in those aged 40–60 over the 3 cycles. These patients may develop pain, reduced function, and rotator cuff arthropathy. There is now an aim to introduce a pathway for these patients across the health board.

408 Blood Parameters as an Early Indicator of Complications Following Oesophagogastric Resection

Aim

Oesophageal and gastric cancers are the eighth and fifth most prevalent cancers with a high degree of morbidity and mortality. Oesophagogastric resections are associated with a high degree of complications postoperatively. Complications following resection are associated with poorer hospital recovery, recurrence of cancer, readmission to hospital and increased mortality. A study was carried out to examine if there was an association between post-operative bloods and the development of complications.

Method

Data was collected from theatre logbooks, Integrated Clinical Environment (ICE) and clinical portal. Patients undergoing oesophagogastric resection for gastric and oesophageal cancer between October 2010 and November 2014 were included. Complications were organised using the Clavien Dindo classification. Data was analysed using the Student’ T test and Chi-Squared test. A P-value of 0.05 was classed as being statiscally significant.

Results

94 patients met the inclusion criteria for this study. 55 patients (58.5%) underwent Oesophagectomy, 18 (19.1%) total gastrectomy and 21 (22.3%) partial gastrectomy. A significant association was seen between development of complications and higher Day 5 White Cell count (WCC) (p = 0.048), lower Day 2–5 Albumin (Day 2 Albumin p = 0.038) and higher Day 2–5 C Reactive Protein (CRP) (Day 2 CRP p<0.001).

Conclusions

This study suggests Albumin, CRP and WCC may be used to predict postoperative complications in patients undergoing oesophagogastric resections for malignancy. Changes in the blood parameters present as early as day 2 postoperatively and can highlight patients who require closer monitoring, allowing earlier re-intervention if required.

403 The Difficulties of Managing Trauma in Elderly Patients in a West of Scotland Trauma Unit

Aim

An increasing number of elderly patients require admission to Trauma & Orthopaedic units throughout Scotland with admissions often complex and lengthy. We aimed to assess the current standard of care within a west of Scotland trauma unit against the 2019 British Orthopaedic Associations Standard of Care (BOAST) - “The care of the older or frail orthopaedic trauma patient” and devise a multi-disciplinary quality improvement strategy.

Method

All patients over the age of 65 admitted to the Trauma & Orthopaedic department of the University Hospital Wishaw between the 1st-14th of August 2020 were included. Online medical records were assessed and compared to the BOAST guideline. Results were presented to Orthopaedic and Care of the elderly (COTE) team and postgraduate teaching before being re-audited from 1st-14th May 2021. Data was analysed using Chi- Squared test.

Results

Cycle one vs Cycle two:

Falls risk assessment was carried out in 50/57(87.7%) vs 49/57(86.0%); Nutritional assessment carried out in 53/57(93.0%) vs 50/57(87.7%); Delirium assessment carried out in 54/57(94.7%) vs 47/57(82.5%). More patients were reviewed by Acute Care of the Elderly nurses 24/57(42.1%) vs 30/57(52.6%). No significant improvement was seen in the percentage of patients reviewed by a COTE consultant:15/57(26.3%) vs 17/57(29.8%) (P = 0.68).

Conclusions

Both cycles show good concordance with the BOAST criteria, including physiotherapy reviews, falls and delirium assessment, however significant deficiencies exist, including the provision of COTE input. This has prompted a reconfiguration of orthogeriatric input for trauma patients, with significant investment in the recruitment of COTE medical staff.

Pulmonary Capillaritis: The Breakdown of the Histologic Features

Introduction/Objective

Capillary inflammation (capillaritis) is rarely the primary pathologic cause of pulmonary hemorrhage. It may coexist with vasculitis. The aim of this study is to investigate the specificity of five histologic features of pulmonary capillaritis previously described by Mark and Ramirez (discussed below). They are usually treated with corticosteroids and cyclophosphamide or azathioprine.

Methods

A retrospective review of patients with a pathologic diagnosis of capillaritis in open lung biopsies was done. The diagnosis was confirmed by two expert pulmonary pathologists. The slides were reviewed and compared to a control group, who also underwent open lung biopsies for clinical suggestion of pulmonary hemorrhage and no pathologic diagnosis of capillaritis. Cases with malignant neoplasms, large and medium size vasculitis syndromes, and diffuse alveolar damage (DAD) were excluded. The five pathologic features of capillaritis were evaluated and scored as negative (0), focal (1+) and moderate to diffuse (2+) in both groups.

Results

Five cases of pulmonary capillaritis and five cases in control group were identified. The etiology of pulmonary capillaritis in the five identified cases included autoimmune diseases, pulmonary hypertension, non-specific interstitial pneumonia, and idiopathic capillaritis. The average score for the morphologic features of capillaritis versus the control group were as follows: Interstitial erythrocytes and/or hemosiderin (2+ vs 2+), fibrinoid necrosis of capillary walls (2+vs 0), intraalveolar septal capillary occlusion by fibrin thrombi (1+ vs 0), neutrophils and nuclear dust in the interstitium, in the fibrin, and in the adjacent alveolar spaces (2+ vs 1+), and fibrin clots attached to interalveolar septa in a sessile manner (2+ vs 1+).

Conclusion

In this small study, we can conclude that fibrinous necrosis is the most specific finding for pulmonary capillaritis while interstitial erythrocytes and/or hemosiderin is least specific. Therefore, in the presence of fibrinous necrosis; in addition to other supporting features; a pathologist is more inclined to communicate a diagnosis of pulmonary capillaritis to the clinicians.

Manganese-Enhanced MRI in Patients with Multiple Sclerosis

BACKGROUND AND PURPOSE

Cellular uptake of the manganese ion, when administered as a contrast agent for MR imaging, can noninvasively highlight cellular activity and disease processes in both animals and humans. The purpose of this study was to explore the enhancement profile of manganese in patients with multiple sclerosis.

MATERIALS AND METHODS

Mangafodipir is a manganese chelate that was clinically approved for MR imaging of liver lesions. We present a case series of 6 adults with multiple sclerosis who were scanned at baseline with gadolinium, then injected with mangafodipir, and followed at variable time points thereafter.

RESULTS

Fourteen new lesions formed during or shortly before the study, of which 10 demonstrated manganese enhancement of varying intensity, timing, and spatial pattern. One gadolinium-enhancing extra-axial mass, presumably a meningioma, also demonstrated enhancement with manganese. Most interesting, manganese enhancement was detected in lesions that formed in the days after mangafodipir injection, and this enhancement persisted for several weeks, consistent with contrast coming from intracellular uptake of manganese. Some lesions demonstrated a diffuse pattern of manganese enhancement in an area larger than that of both gadolinium enhancement and T2-FLAIR signal abnormality.

CONCLUSIONS

This work demonstrates the first use of a manganese-based contrast agent to enhance MS lesions on MR imaging. Multiple sclerosis lesions were enhanced with a temporal and spatial profile distinct from that of gadolinium. Further experiments are necessary to uncover the mechanism of manganese contrast enhancement as well as cell-specific uptake.

Separation of Mycobacterium smegmatis From a Mixed Culture Using the Cell Wall Binding Domain of D29 Mycobacteriophage Endolysin

Pathological infection caused by Mycobacterium tuberculosis is still a major global health concern. Traditional diagnostic methods are time-consuming, less sensitive, and lack high specificity. Due to an increase in the pathogenic graph of mycobacterial infections especially in developing countries, there is an urgent requirement for a rapid, low cost, and highly sensitive diagnostic method. D29 mycobacteriophage, which is capable of infecting and killing M. tuberculosis, projects itself as a potential candidate for the development of novel diagnostic methods and phage therapy of mycobacterial infections. In our previous study, we showed that the cell wall binding domain [C-terminal domain (CTD)] located at the C-terminal end of the D29 mycobacteriophage LysA endolysin very selectively binds to the peptidoglycan (PG) of Mycobacterium smegmatis and M. tuberculosis. Here, by using M. smegmatis as model organism and by exploiting the PG binding ability of CTD, we have developed a method to isolate M. smegmatis cells from a mixed culture via magnetic separation. We show that green fluorescent protein (GFP)-tagged CTD (CTD-GFP) can bind to M. smegmatis cells in vitro after treatment with non-ionic detergent Triton X-100. Fluorescence-based assays show that CTD-GFP binding to M. smegmatis cells is highly specific and stable, and is not disrupted by an excess of either GFP or BSA. We further fused CTD with glutathione-S-transferase (GST) to generate CTD-GST protein and carried out an anti-GST antibody-mediated coating of CTD-GST on Dynabeads. This allowed us to perform successful magnetic separation of M. smegmatis from a mixed culture of bacteria having both Gram-negative and Gram-positive bacteria. Furthermore, the separated cells could be confirmed by a simple PCR. Thus our assay allows us to separate and identify M. smegmatis from a mixed culture.

Understanding the role of the lysozyme-like domain of D29 mycobacteriophage-encoded endolysin in host cell lysis and phage propagation

Mycobacteriophages are viruses that infect and kill mycobacteria. The peptidoglycan hydrolase, lysin A (LysA), coded by one of the most potent mycobacteriophages, D29, carries two catalytic domains at its N-terminus and a cell wall-binding domain at its C-terminus. Here, we have explored the importance of the centrally located lysozyme-like catalytic domain (LD) of LysA in phage physiology. We had previously identified an R198A substitution that causes inactivation of the LD when it is present alone on a polypeptide. Here, we show that upon incorporation of the same mutation (i.e. R350A) in full-length LysA, the protein demonstrates substantially reduced activity in vitro, even in the presence of the N-terminal catalytic domain, and has less efficient mycobacterial cell lysis ability when it is expressed in Mycobacterium smegmatis. These data suggest that an active LD is required for the full-length protein to function optimally. Moreover, a mutant D29 phage harbouring this substitution (D29^R350A) in its LysA protein shows significantly delayed host M. smegmatis lysis. However, the mutant phage demonstrates an increase in burst size and plaque diameter. Taken together, our data show the importance of an intact LD region in D29 LysA PG hydrolase, and indicate an evolutionary advantage over other phages that lack such a domain in their endolysins.

An intra-operative device for parallel drilling and femoral landmark estimation during medial patellofemoral ligament reconstructive surgery

ABSTRACT BACKGROUND: The aim of this study was to design and test a device to guide medial patellofemoral reconstruction surgeries. Materials and methods: A three-dimensional (3D) printed, modular and cost-effective medial patellofemoral ligament (MPFL) reconstruction guide, Pat-Rig, was designed with parallel holes running in the medio-lateral direction. This device was manufactured using a commercial additive manufacturing facility, and bench tested using a custom-built test rig. CT scans of patella bones were reconstructed, and the device was tested on four 3D-printed patellas of various sizes. RESULTS: The device was successful in guiding the surgical drill into the patella to drill parallel holes adhering to the current surgical requirements and specifications. The device was augmented with an innovative radiopaque scale which can allow the surgeon to accurately predict the landmarks to drill and measure the drill depth of the tunnels. CONCLUSION: There are no devices on the market that accurately predict the drill locations on the patella during MPFL reconstruction surgeries. The device, Pat-Rig, was found to overcome the current limitations of the MPFL surgeries and was able to provide satisfactory surgical guidance during the reconstruction. Level of evidence: Level 5 Keywords: knee surgery, patella, orthopaedic, MPFL reconstruction, 3D-printed, novel surgical device.

P2853Contemporary reporting of acute complications from implantable cardioverter defibrillator surgery

Background

Defibrillator placement carries an inherent risk to the patient. Traditionally, major adverse events defined as cardiac arrest, tamponnade, pneumothorax, infection requiring re-operation, MI and CVA within 30 days are reported to occur between 3 and 4%. Minor complications such as heamatomae or lead dislodgement are reported between 8 and 13%. Novel lead technologies, protocolised programming and reduced use of Heparin bridging have been reported to reduce adverse outcomes. However, patients are still typically monitored in hospital for 24 hours to mitigate these risks. There is little evidence that discharge delay is effective yet incurs significant additional costs.

Purpose

We sought to evaluate the frequency and timing of adverse events relating to defibrillator surgery (ICD and CRT-D) at a large Canadian tertiary care center (UOHI).

Methods

We retrospectively reviewed all patients who received a defibrillator placed from 1st April 2013 to 31st March 2018 inclusive. Patient comorbidities were extracted from the hospital electronic medical record (EMR) system. Device related information and complications were extracted from UOHI PaceartTM system and EMR and cross referenced with physician remuneration databases.

Results

A total of 2221 procedures were performed on 2153 patients (78% male, mean age 65 years). The majority (60%) of defibrillator implants were de novo, with 884 (40%) pulse generator replacements/ upgrades and 868 (39%) defibrillators had CRT capability. Patients were routinely discharged within 24 hours of ICD surgery. Post-operative follow up ≥30 days was complete in 97% patients. Major adverse events occurred within 30 days in 9 patients (0.4%); 9 (100%) were infection requiring re-operation. An additional 32 patients (1.5%) required repeat interventions or readmission within 30 days of implant, most commonly due to lead dislodgement. Only 2 patients required readmission within 24 hours of surgery (0.1%). All procedure-related adverse events during clinical follow up (≤5 years) were 131 (5.9%) occurring in 122 patients. There were no apparent predictors of adverse events in this cohort.

Conclusion(s)

Contemporary risks to patients undergoing defibrillator surgery are considerably lower than that reported in 2010. The risk of infection appears constant despite increased antibiosis. Patients receiving an ICD or CRT-D can safely be discharged within 24 hours if no complications are apparent.

Acknowledgement/Funding

None

P1872Canadian electrophysiology labs registry report update 2011–2018

Background

Interventional cardiac electrophysiology (EP) is rapidly evolving; a nationwide registry was established and re-administered since 2011 to conduct a periodic review of resource allocation across Canada.

Methods

The registry collects annual data on EP lab infrastructure, imaging, tools, human resources, procedural volumes, and wait times. Leading physicians from each EP lab were contacted electronically.

Results

All Canadian EP centres were identified (n=30); 50% and 45% of active centres participated in the last 2 instalments of the registry. Since 2011, data has been consistently obtained from 11 university-affiliated centres. Table 1 reports trends in procedural volumes and operators. Figure 1 depicts the ablations done per operator. The mean wait time to see an electrophysiologist for an initial non-urgent consult is 23 weeks. The wait time between an EP consult and ablation date is 17.8 weeks for simple ablation, 15.9 weeks for VT ablation, and 30.1 weeks for AF ablation. On average centres have 2 (range: 1–4) rooms equipped for ablations; each centre uses the EP lab an average of 7 shifts per week. While diagnostic studies and radiofrequency ablations are performed in all centres, point-by-point cryoablation is available in 85% and cryoballoon in 77% of the centres; 38% of the respondents use circular ablation techniques.

Trends in procedural volumes + operators 2015–2016 2013–2014 2011–2012 Procedures per operator 117±70 120±68 113±42 Procedures per centre 498±299 477±245 446±237 Ratio of staff to trainees 2.0:1 1.6:1 1.5:1 Full time physicians per centre 4.1 (0–7) 4.1 (1–7) 3.5 (0–7) Nurses trained specifically for EP 4.6 (0–10) 4.4 (0–10) n/a Ablation procedures volume:   AV Reciprocal Tachycardia 12% 10% 11%   AV Nodal Re-entry Tachycardia 18% 19% 23%   Atrial Fibrillation/Atypical Flutter 33% 35% 30%   Typical Flutter 20% 14% 19%   Ventricular Tachycardia 8% 8% 10%   Total annual ablations in all respondent centres 5478 5243 4908 Mean ± standard deviation. Staff (full-time + part-time prorated to 0.5).

Annual ablation volumes per operator

Conclusion

This initiative provides contemporary data on invasive EP practices. The results show feasibility in data collection which will serve as a reference for decisions regarding resource planning.

Manganese-Enhanced MRI of the Brain in Healthy Volunteers

BACKGROUND AND PURPOSE

The manganese ion is used as an intracellular MR imaging contrast agent to study neuronal function in animal models, but it remains unclear whether manganese-enhanced MR imaging can be similarly useful in humans. Using mangafodipir (Teslascan, a chelated manganese-based contrast agent that is FDA-approved), we evaluated the dynamics of manganese enhancement of the brain and glandular structures in the rostral head and neck in healthy volunteers.

MATERIALS AND METHODS

We administered mangafodipir intravenously at a rate of 1 mL/minute for a total dose of 5 μmol/kg body weight. Nine healthy adult volunteers (6 men/3 women; median age, 43 years) completed baseline history and physical examination, 3T MR imaging, and blood work. MR imaging also followed mangafodipir administration at various time points from immediate to 7 days, with delayed scans at 1-3 months.

RESULTS

The choroid plexus and anterior pituitary gland enhanced within 10 minutes of infusion, with enhancement persisting up to 7 and 30 days, respectively. Exocrine (parotid, submandibular, sublingual, and lacrimal) glands also enhanced avidly as early as 1 hour postadministration, generally resolving by 1 month; 3 volunteers had residual exocrine gland enhancement, which resolved by 2 months in 1 and by 3 months in the other 2. Mangafodipir did not affect clinical parameters, laboratory values, or T1-weighted signal in the basal ganglia.

CONCLUSIONS

Manganese ions released from mangafodipir successfully enable noninvasive visualization of intra- and extracranial structures that lie outside the blood-brain barrier without adverse clinical effects, setting the stage for future neuroradiologic investigation in disease.

Interferon alfa-2a maintenance after salvage autologous stem cell transplantation in atypical mycosis fungoides with central nervous system involvement

Mycosis fungoides (MF) is a primary cutaneous T-cell lymphoma with unfavourable prognosis for patients with advanced stages of the disease. Refractory disease and advanced-stage disease require systemic therapy. We report on a rare case of an atypical predominantly CD8⁺ folliculotropic MF, a subtype of MF with poorer prognosis, in a 59-year-old woman. She was initially diagnosed with MF restricted to the skin, of T3N0M0B0/stage IIB according to the current World Health Organization-European Organisation for Research and Treatment of Cancer classification. First-line treatment with local percutaneous radiotherapy in combination with systemic interferon alfa-2a resulted in complete remission. However, 21 months later the disease progressed to T3N0M1B0/stage IVB with development of cerebral manifestation and thus very poor prognosis. Allogeneic stem cell transplantation (SCT) was not a therapeutic option due to the lack of a suitable donor. We initiated methotrexate and cytarabine chemotherapy, followed by high-dose chemotherapy with thiotepa and carmustine with autologous SCT. Despite rapid response and complete remission of the cerebral lesions, disease recurrence of the skin occurred soon after. Interestingly, readministration of interferon alfa-2a as a maintenance treatment after the salvage autologous SCT resulted in a durable complete remission during the follow-up period of currently 17 months after autologous SCT. What's already known about this topic? Mycosis fungoides is a primary cutaneous T-cell lymphoma with unfavourable prognosis for the advanced stages of the disease. A refractory course of disease requires systemic therapy. What does this study add? We report on an unusual case of a patient with mycosis fungoides with cerebral involvement, in which a durable complete remission was achieved upon autologous stem cell therapy and interferon alfa-2a maintenance therapy.

Identification of Chronic Active Multiple Sclerosis Lesions on 3T MRI

BACKGROUND AND PURPOSE

MR imaging-pathologic studies have reported that paramagnetic rims on 7T susceptibility-based MR imaging identify, in vivo, the subset of MS lesions with compartmentalized inflammation at the lesion edge and associated remyelination failure. Here, we assessed the reliability of detecting these rims on high-resolution 3T phase images.

MATERIALS AND METHODS

High-resolution T2* and phase MR imaging was collected in 20 patients with MS at 3T (3D segmented EPI, 0.65 mm³) and 7T (2D gradient-echo, 0.2 × 0.2 × 1 mm) MR imaging. In each case, 5 discrete chronic (nonenhancing) MS lesions were selected on T2 FLAIR images for rim evaluation. Five raters experienced in MS imaging contributed to the rim assessment, of whom 3 worked independently on 3T data, and 2, on 7T data. Consensus agreement was reached for both 3T and 7T rim evaluations. Discrepancies between 3T and 7T were discussed, and consensus was reached.

RESULTS

Phase rims were seen in 34 lesions at 7T and in 36 lesions at 3T by consensus. Inter- and intrarater reliability were "substantial/good" both at 3T and 7T analysis (Cohen κ, >0.71). Based on consensus agreement, the reliability of rim visualization at 3T versus 7T was 0.78 (κ) with a pair-wise agreement of 90%. More lesions were judged to be false-positive or false-negative at 3T than at 7T.

CONCLUSIONS

Nearly all 7T paramagnetic rims can also be seen at 3T. Imaging at 3T opens the possibility of implementing paramagnetic rims as an outcome measure in multicenter, MR imaging-based clinical trials aimed at treating perilesional persistent inflammation and its potential effects on remyelination.

An Automated Statistical Technique for Counting Distinct Multiple Sclerosis Lesions

BACKGROUND AND PURPOSE

Lesion load is a common biomarker in multiple sclerosis, yet it has historically shown modest association with clinical outcome. Lesion count, which encapsulates the natural history of lesion formation and is thought to provide complementary information, is difficult to assess in patients with confluent (ie, spatially overlapping) lesions. We introduce a statistical technique for cross-sectionally counting pathologically distinct lesions.

MATERIALS AND METHODS

MR imaging was used to assess the probability of a lesion at each location. The texture of this map was quantified using a novel technique, and clusters resembling the center of a lesion were counted. Validity compared with a criterion standard count was demonstrated in 60 subjects observed longitudinally, and reliability was determined using 14 scans of a clinically stable subject acquired at 7 sites.

RESULTS

The proposed count and the criterion standard count were highly correlated (r = 0.97, P < .001) and not significantly different (t₅₉ = -.83, P = .41), and the variability of the proposed count across repeat scans was equivalent to that of lesion load. After accounting for lesion load and age, lesion count was negatively associated (t₅₈ = -2.73, P < .01) with the Expanded Disability Status Scale. Average lesion size had a higher association with the Expanded Disability Status Scale (r = 0.35, P < .01) than lesion load (r = 0.10, P = .44) or lesion count (r = -.12, P = .36) alone.

CONCLUSIONS

This study introduces a novel technique for counting pathologically distinct lesions using cross-sectional data and demonstrates its ability to recover obscured longitudinal information. The proposed count allows more accurate estimation of lesion size, which correlated more closely with disability scores than either lesion load or lesion count alone.

Improved Visualization of Cortical Lesions in Multiple Sclerosis Using 7T MP2RAGE

BACKGROUND AND PURPOSE

Cortical lesions are common and often extensive in multiple sclerosis but are difficult to visualize by MRI, leaving important questions about their clinical implications and response to therapy unanswered. Our aim was to determine whether cortical lesions are better visualized using magnetization prepared 2 rapid acquisition gradient echoes (MP2RAGE) than T2*-weighted imaging on 7T MR imaging.

MATERIALS AND METHODS

Brain MR imaging using T1-weighted MP2RAGE at 500-μm isotropic resolution, T2*-weighted gradient-echo, and T2*-weighted segmented echo-planar imaging sequences were collected for 13 patients with MS and 5 age-matched neurologically healthy controls on a 7T research system. One MS case underwent postmortem MR imaging including gradient-echo and MP2RAGE sequences, after which cortical lesions seen on MR imaging were assessed with immunohistochemistry.

RESULTS

MP2RAGE detected 203 cortical lesions (median, 16 lesions/case; interquartile range, 15), compared to 92 with T2*gradient-echo (median, 7; interquartile range, 8; P < .001) and 81 with T2*EPI (median, 7; interquartile range, 5; P < .001). This increase in lesion number detected on MP2RAGE versus T2* was observed for juxtacortical, leukocortical, and intracortical lesions. Forty-three percent of all cortical lesions were identified only on MP2RAGE. White matter lesion volume correlated with total juxtacortical (r = 0.86, P < .001) and leukocortical lesion volume (r = 0.70, P < .01) but not intracortical lesion volume, suggesting that pathophysiology may differ by lesion type. Of 4 suspected lesions seen on postmortem imaging, 3 were found to be true cortical lesions while 1 represented postmortem tissue damage.

CONCLUSIONS

A combination of MP2RAGE and T2*-weighted imaging at 7T improved detection of cortical lesions and should enable longitudinal studies to elucidate their spatiotemporal dynamics and clinical implications.

Heparin-induced thrombocytopenia associated with thrombotic microangiopathy

Some cases of thrombotic microangiopathy (TMA) are refractory to plasma exchange therapy (PE) with persistence or recurrence of thrombocytopenia. We report two patients suffering from TMA of different aetiologies (associated with disseminated malignancy, typical haemolytic uraemic syndrome) with recurrent or persistent thrombocytopenia despite adequate therapy including PE. Since both patients were exposed to unfractionated heparin, heparin-induced thrombocytopenia (HIT) was suspected as a cause. Pretest probabilities for HIT were intermediate. ELISA for PF4/heparin antibodies was strongly positive in both cases, and HIT was confirmed by heparin-induced platelet activation assay. Anticoagulation with lepirudin was initiated, with subsequent rapid increase of the platelet count.

TMA might represent a predisposition for HIT. This could be due to TMA-related platelet activation with increased PF4 release. In TMA patients exposed to heparin and with refractory or rapidly recurrent thrombocytopenia HIT should always be considered as a possible cause.

Transverse relaxation of cerebrospinal fluid depends on glucose concentration

PURPOSE

To evaluate the biophysical processes that generate specific T₂ values and their relationship to specific cerebrospinal fluid (CSF) content.

MATERIALS AND METHODS

CSF T_2s were measured ex vivo (14.1T) from isolated CSF collected from human, rat and non-human primate. CSF T_2s were also measured in vivo at different field strength in human (3 and 7T) and rodent (1, 4.7, 9,4 and 11.7T) using different pulse sequences. Then, relaxivities of CSF constituents were measured, in vitro, to determine the major molecule responsible for shortening CSF T₂ (2s) compared to saline T₂ (3s). The impact of this major molecule on CSF T₂ was then validated in rodent, in vivo, by the simultaneous measurement of the major molecule concentration and CSF T₂.

RESULTS

Ex vivo CSF T₂ was about 2.0s at 14.1T for all species. In vivo human CSF T₂ approached ex vivo values at 3T (2.0s) but was significantly shorter at 7T (0.9s). In vivo rodent CSF T₂ decreased with increasing magnetic field and T₂ values similar to the in vitro ones were reached at 1T (1.6s). Glucose had the largest contribution of shortening CSF T₂in vitro. This result was validated in rodent in vivo, showing that an acute change in CSF glucose by infusion of glucose into the blood, can be monitored via changes in CSF T₂ values.

CONCLUSION

This study opens the possibility of monitoring glucose regulation of CSF at the resolution of MRI by quantitating T₂.

Volumetric Analysis from a Harmonized Multisite Brain MRI Study of a Single Subject with Multiple Sclerosis

BACKGROUND AND PURPOSE

MR imaging can be used to measure structural changes in the brains of individuals with multiple sclerosis and is essential for diagnosis, longitudinal monitoring, and therapy evaluation. The North American Imaging in Multiple Sclerosis Cooperative steering committee developed a uniform high-resolution 3T MR imaging protocol relevant to the quantification of cerebral lesions and atrophy and implemented it at 7 sites across the United States. To assess intersite variability in scan data, we imaged a volunteer with relapsing-remitting MS with a scan-rescan at each site.

MATERIALS AND METHODS

All imaging was acquired on Siemens scanners (4 Skyra, 2 Tim Trio, and 1 Verio). Expert segmentations were manually obtained for T1-hypointense and T2 (FLAIR) hyperintense lesions. Several automated lesion-detection and whole-brain, cortical, and deep gray matter volumetric pipelines were applied. Statistical analyses were conducted to assess variability across sites, as well as systematic biases in the volumetric measurements that were site-related.

RESULTS

Systematic biases due to site differences in expert-traced lesion measurements were significant (P < .01 for both T1 and T2 lesion volumes), with site explaining >90% of the variation (range, 13.0-16.4 mL in T1 and 15.9-20.1 mL in T2) in lesion volumes. Site also explained >80% of the variation in most automated volumetric measurements. Output measures clustered according to scanner models, with similar results from the Skyra versus the other 2 units.

CONCLUSIONS

Even in multicenter studies with consistent scanner field strength and manufacturer after protocol harmonization, systematic differences can lead to severe biases in volumetric analyses.

Optimized T1-MPRAGE sequence for better visualization of spinal cord multiple sclerosis lesions at 3T

BACKGROUND AND PURPOSE

Spinal cord lesions are highly prevalent in MS, and their visualization can help both in diagnosis and patient follow-up. However, the sensitivity of MR imaging to spinal cord lesions remains poor, primarily because of suboptimal contrast between lesions and a normal-appearing cord. Here, we propose an optimized 3D MPRAGE sequence for improved detection of MS lesions in the spinal cord at 3T.

MATERIALS AND METHODS

Images were acquired by use of T2 FSE, STIR, T1-gradient recalled-echo (for T1 mapping), and T1-MPRAGE in the sagittal plane, and T2*-weighted scans in the axial plane, on 40 patients with MS and 7 healthy volunteers. Two observers qualitatively evaluated the images for lesion conspicuity. Lesions seen between the C1 and C4 segments in 10 randomly selected patients with MS were further evaluated quantitatively for contrast-to-noise ratio between the lesion and normal-appearing cord, and for lesion burden.

RESULTS

Spinal cord lesions were more conspicuous on the optimized T1-MPRAGE sequence than on any other sequence tested. Detailed analysis revealed that lesions were almost 3 times more conspicuous (P < .01), and the total lesion volume was 2 times greater (P < .05, n=10), in the T1-MPRAGE sequence compared with the standard STIR sequence. Correlation of clinical disability (Expanded Disability Status Score) with lesion load from each sequence also demonstrated the importance of the improved lesion conspicuity with T1-MPRAGE.

CONCLUSIONS

The optimized T1-MPRAGE sequence described here improves the reliability of lesion visualization and estimation of lesion burden, especially when used in conjunction with other well-established clinical sequences.

Characterizing cognitive deficits and dementia in an aging urban population in India

Rapid rise in the population of older adults in India will lead to the need for increased health care services related to diagnosis, management, and long-term care for those with dementia and cognitive impairment. A direct approach for service provision through memory clinics can be an effective, successful, and sustaining means of delivering specialized health care services. We have established a memory clinic in Mumbai, India by employing the diverse clinical skills available in Indian academic institutions, diagnostic and research expertise of clinicians and psychologists, and the support of the U.S. National Institutes of Health. Our project involved recruitment of patients, clinical and neuropsychological assessment, and standardized diagnostic procedures, demonstrating the feasibility of using research methods to develop a memory clinic. In this paper, we describe the development of a community-based memory clinic in urban India, including linguistic and cultural factors and present detailed results, including diagnostic characterization, on 194 subjects with various stages of cognitive deficits. Our findings support the feasibility of developing a memory clinic in a public hospital and successful use of research diagnostic criteria to categorize cognitive deficits observed in this population, which may be used to inform the development of other such clinics.

Presymptomatic spinal cord neurometabolic findings in SOD1-positive people at risk for familial ALS

OBJECTIVE

It has been speculated that amyotrophic lateral sclerosis (ALS) is characterized by a premanifest period during which neurodegeneration precedes the appearance of clinical manifestations. Magnetic resonance spectroscopy (MRS) was used to measure ratios of neurometabolites in the cervical spine of asymptomatic individuals with a mutation in the SOD1 gene (SOD1+) and compare their neurometabolic ratios to patients with ALS and healthy controls.

METHODS

A cross-sectional study of (1)H-MRS of the cervical spine was performed on 24 presymptomatic SOD1+ volunteers, 29 healthy controls, and 23 patients with ALS. All presymptomatic subjects had no symptoms of disease, normal forced vital capacity, and normal electromyographic examination. Relative concentrations of choline (Cho), creatine (Cr), myo-inositol (Myo), and N-acetylaspartate (NAA) were determined.

RESULTS

NAA/Cr and NAA/Myo ratios are reduced in both SOD1+ subjects (39.7%, p = 0.001 and 18.0%, p = 0.02) and patients with ALS (41.2%, p < 0.001 and 24.0%, p = 0.01) compared to controls. Myo/Cr is reduced (10.3%, p = 0.02) in SOD1+ subjects compared to controls, but no difference was found between patients with ALS and controls. By contrast, NAA/Cho is reduced in patients with ALS (24.0%, p = 0.002), but not in presymptomatic SOD1+ subjects compared to controls.

CONCLUSIONS

Changes in neurometabolite ratios in the cervical spinal cord are evident in presymptomatic SOD1+ individuals in advance of symptoms and clinical or electromyographic signs of disease. These changes reflect a reduction in NAA/Cr and NAA/Myo. Neurometabolic changes in this population resemble changes observed in patients with clinically apparent ALS. This suggests that neurometabolic changes occur early in the course of the disease process.