Paramagnetic rim lesions predict greater long-term relapse rates and clinical progression over 10 years

BACKGROUND

Paramagnetic rim lesions (PRLs) have been linked to higher clinical disease severity and relapse frequency. However, it remains unclear whether PRLs predict future, long-term disease progression.

OBJECTIVES

The study aimed to assess whether baseline PRLs were associated with subsequent long-term (10 years) Expanded Disability Status Scale (EDSS) increase and relapse frequency and, if so, whether PRL-associated EDSS increase was mediated by relapse.

METHODS

This retrospective analysis included 172 people with multiple sclerosis (pwMS) with 1868 yearly clinical visits over a mean follow-up time of 10.2 years. 3T magnetic resonance imaging (MRI) was acquired at baseline and PRLs were assessed on quantitative susceptibility mapping (QSM) images. The associations between PRLs, relapse, and rate of EDSS change were assessed using linear models.

RESULTS

PRL+ pwMS had greater overall annual relapse rate (β = 0.068; p = 0.010), three times greater overall odds of relapse (exp(β) = 3.472; p = 0.009), and greater rate of yearly EDSS change (β = 0.045; p = 0.010) than PRL- pwMS. Greater PRL number was associated with greater odds of at least one progression independent of relapse activity (PIRA) episode over follow-up (exp(β) = 1.171, p = 0.009). Mediation analysis showed that the association between PRL presence (yes/no) and EDSS increase was 96.7% independent of relapse number.

CONCLUSION

PRLs are a marker of aggressive ongoing disease inflammatory activity, including more frequent future clinical relapses and greater long-term, relapse-independent disability progression.

Reliability of paramagnetic rim lesion classification on quantitative susceptibility mapping (QSM) in people with multiple sclerosis: Single-site experience and systematic review

BACKGROUND

Recent developments in iron-sensitive MRI techniques have enabled visualization of chronic active lesions as paramagnetic rim lesions (PRLs) in vivo. Although PRLs have potential as a diagnostic and prognostic tool for multiple sclerosis (MS), limited studies have reported the reliability of PRL assessment. Further evaluation of PRL reliability, through original investigations and review of PRL literature, are warranted.

METHODS

A single-center cohort study was conducted to evaluate the inter-rater reliability of PRL identification on quantitative susceptibiltiy mapping (QSM) in 10 people with MS, 5 people with clinically isolated syndrome, and 5 healthy controls. An additional systematic literature search was then conducted of published PRL reliability data, and these results were synthesized.

RESULTS

In the single-center study, both inter-rater and intra-rater reliability of per-subject PRL number were at an "Excellent" (intraclass correlation coefficient (ICC) of 0.901 for both) level with only 2-years lesion classification experience. Across the reported literature values, reliability of per-lesion rim presence was on average "Near perfect" (for intra-rater; Cohen's κ = 0.833) and "Substantial" (for inter-rater; Cohens κ = 0.687), whereas inter-rater reliability of per-subject PRL number was "Good" (ICC = 0.874). Only 4/22 studies reported complete information on rater experience, rater level of training, detailed PRL classification criteria, and reliability cohort size and disease subtypes.

CONCLUSION

PRLs can be reliably detected both at per-lesion and per-subject level. We recommend that future PRL studies report detailed reliability results, including rater experience level, and use a standardized set of reliability metrics (Cohen's κ or ICC) for improved comparability between studies.

Paramagnetic rim lesions are associated with greater incidence of relapse and worse cognitive recovery following relapse

BACKGROUND

Paramagnetic rim lesions (PRL) may be linked to relapse risk of people with relapsing-remitting multiple sclerosis (pwRRMS).

OBJECTIVE

To determine the relationship between presence of PRL lesions and cognitive recovery after relapse.

METHODS

PRL load was compared between acutely relapsing pwRRMS and matched stable pwRRMS controls (each group n = 21). In addition, cognitive recovery was compared between acutely relapsing pwRRMS with at least one PRL (PRL+) and those without any PRL (PRL-).

RESULTS

Acutely relapsing pwRRMS had significantly greater prevalence and number of PRL (p = 0.004 and p = 0.003) compared with stable controls. These findings remained significant after adjusting for global neuroinflammatory burden (enhancing and non-enhancing lesions). In addition, acutely relapsing PRL + pwRRMS (n = 10) had worse recovery of verbal memory following relapse compared with acutely relapsing PRL - pwRRMS (n = 7; p = 0.027).

CONCLUSION

These findings may partially explain previously suggested associations between presence of PRL with more severe disease course.

Susceptibility networks reveal independent patterns of brain iron abnormalities in multiple sclerosis

Brain iron homeostasis is necessary for healthy brain function. MRI and histological studies have shown altered brain iron levels in the brains of patients with multiple sclerosis (MS), particularly in the deep gray matter (DGM). Previous studies were able to only partially separate iron-modifying effects because of incomplete knowledge of iron-modifying processes and influencing factors. It is therefore unclear to what extent and at which stages of the disease different processes contribute to brain iron changes. We postulate that spatially covarying magnetic susceptibility networks determined with Independent Component Analysis (ICA) reflect, and allow for the study of, independent processes regulating iron levels. We applied ICA to quantitative susceptibility maps for 170 individuals aged 9-81 years without neurological disease ("Healthy Aging" (HA) cohort), and for a cohort of 120 patients with MS and 120 age- and sex-matched healthy controls (HC; together the "MS/HC" cohort). Two DGM-associated "susceptibility networks" identified in the HA cohort (the Dorsal Striatum and Globus Pallidus Interna Networks) were highly internally reproducible (i.e. "robust") across multiple ICA repetitions on cohort subsets. DGM areas overlapping both robust networks had higher susceptibility levels than DGM areas overlapping only a single robust network, suggesting that these networks were caused by independent processes of increasing iron concentration. Because MS is thought to accelerate brain aging, we hypothesized that associations between age and the two robust DGM-associated networks would be enhanced in patients with MS. However, only one of these networks was altered in patients with MS, and it had a null age association in patients with MS rather than a stronger association. Further analysis of the MS/HC cohort revealed three additional disease-related networks (the Pulvinar, Mesencephalon, and Caudate Networks) that were differentially altered between patients with MS and HCs and between MS subtypes. Exploratory regression analyses of the disease-related networks revealed differential associations with disease duration and T2 lesion volume. Finally, analysis of ROI-based disease effects in the MS/HC cohort revealed an effect of disease status only in the putamen ROI and exploratory regression analysis did not show associations between the caudate and pulvinar ROIs and disease duration or T2 lesion volume, showing the ICA-based approach was more sensitive to disease effects. These results suggest that the ICA network framework increases sensitivity for studying patterns of brain iron change, opening a new avenue for understanding brain iron physiology under normal and disease conditions.

Reproducing the effect of hippocampal network-targeted transcranial magnetic stimulation on episodic memory

Repetitive transcranial magnetic stimulation (rTMS) targeted to the hippocampal network via the inferior parietal cortex (HN-Stim) can strengthen hippocampal-cortical connectivity and improve episodic memory, offering a potential clinical intervention. However, acceptance of this technique has been tempered by the infrequent reproduction of findings in rTMS research on cognitive processes. We tested the reproducibility of the HN-Stim effect on episodic memory in our laboratory using different procedures from those previously published. We tested episodic memory in 29 participants before, one day, and one week after, three consecutive days of 20 Hz HN-Stim. Participants received stimulation targeted to either the area of inferior parietal cortex maximally connected to the left anterior hippocampus (HN-Stim; N = 14) or the vertex (control; N = 15), where we expected no effect. HN-Stim increased episodic memory performance one day, but not one week, after the last stimulation session. While failing to reproduce the lasting beneficial effect on memory found by others after five days of treatment, we found robust effects on behavior 24 h after treatment. HN-Stim is a safe and reliable means of enhancing episodic memory and may have potential for boosting learning and treating memory deficits.

A direct test of competitive versus cooperative episodic-procedural network dynamics in human memory

Classical lesion studies led to a consensus that episodic and procedural memory arises from segregated networks identified with the hippocampus and the caudate nucleus, respectively. Neuroimaging studies, however, show that competitive and cooperative interactions occur between networks during memory tasks. Furthermore, causal experiments to manipulate connectivity between these networks have not been performed in humans. Although nodes common to both networks, such as the precuneus and ventrolateral thalamus, may mediate their interaction, there is no experimental evidence for this. We tested how network-targeted noninvasive brain stimulation affects episodic-procedural network interactions and how these network manipulations affect episodic and procedural memory in healthy young adults. Compared to control (vertex) stimulation, hippocampal network-targeted stimulation increased within-network functional connectivity and hippocampal connectivity with the caudate. It also increased episodic, relative to procedural, memory, and this persisted one week later. The differential effect on episodic versus procedural memory was associated with increased functional connectivity between the caudate, precuneus, and ventrolateral thalamus. These findings provide direct evidence of episodic-procedural network competition, mediated by regions common to both networks. Enhanced hippocampal network connectivity may boost episodic, but decrease procedural, memory by co-opting resources shared between networks.

Anesthesia providers' perspectives on abortion provision: deductive findings from a qualitative study

INTRODUCTION

A clinician's willingness to provide abortion care is complex. Anesthesia providers' experiences in providing anesthesia for abortion are not well studied. We aimed to explore anesthesia providers' perspectives on abortion provision.

METHODS

We conducted semi-structured, qualitative interviews with currently practising anesthesia providers in the southeastern United States. Participants were recruited from scientific meetings of two regional anesthesiology organizations and via snowball sampling. A semi-structured interview guide included domains of standardized second trimester abortion cases and personal abortion attitudes. Data were coded and analyzed iteratively using both inductive and deductive approaches with MAXQDA software. Deductive results are presented.

RESULTS

Fifteen participants completed interviews from February 2018 to February 2019, at which point thematic saturation occurred. Participants represented a range of provider type, years of experience, workplace setting, and prior abortion experience. Participants demonstrated varied personal abortion attitudes, with greater acceptability of maternal or fetal health indications than social or financial indications for abortion. Most participants were willing to provide anesthesia for abortion in specific clinical scenarios.

CONCLUSIONS

Southeastern United States anesthesia providers hold a spectrum of personal views on abortion and are willing to provide anesthesia for second trimester abortion in specific clinical scenarios. Findings may inform future research or professional development activities, which are important efforts toward improving multidisciplinary abortion care.

Multiple parietal pathways are associated with rTMS-induced hippocampal network enhancement and episodic memory changes

Repetitive transcranial magnetic stimulation (rTMS) of the inferior parietal cortex (IPC) increases resting-state functional connectivity (rsFC) of the hippocampus with the precuneus and other posterior cortical areas and causes proportional improvement of episodic memory. The anatomical pathway(s) responsible for the propagation of these effects from the IPC is unknown and may not be direct. In order to assess the relative contributions of candidate pathways from the IPC to the MTL via the parahippocampal cortex and precuneus, to the effects of rTMS on rsFC and memory improvement, we used diffusion tensor imaging to measure the extent to which individual differences in fractional anisotropy (FA) in these pathways accounted for individual differences in response. FA in the IPC-parahippocampal pathway and several MTL pathways predicted changes in rsFC. FA in both parahippocampal and hippocampal pathways was related to changes in episodic, but not procedural, memory. These results implicate pathways to the MTL in the enhancing effect of parietal rTMS on hippocampal rsFC and memory.

Identifying site- and stimulation-specific TMS-evoked EEG potentials using a quantitative cosine similarity metric

The ability to interpret transcranial magnetic stimulation (TMS)-evoked electroencephalography (EEG) potentials (TEPs) is limited by artifacts, such as auditory evoked responses produced by discharge of the TMS coil. TEPs generated from direct cortical stimulation should vary in their topographical activity pattern according to stimulation site and differ from responses to sham stimulation. Responses that do not show these effects are likely to be artifactual. In 20 healthy volunteers, we delivered active and sham TMS to the right prefrontal, left primary motor, and left posterior parietal cortex and compared the waveform similarity of TEPs between stimulation sites and active and sham TMS using a cosine similarity-based analysis method. We identified epochs after the stimulus when the spatial pattern of TMS-evoked activation showed greater than random similarity between stimulation sites and sham vs. active TMS, indicating the presence of a dominant artifact. To do this, we binarized the derivatives of the TEPs recorded from 30 EEG channels and calculated cosine similarity between conditions at each time point with millisecond resolution. Only TEP components occurring before approximately 80 ms differed across stimulation sites and between active and sham, indicating site and condition-specific responses. We therefore conclude that, in the absence of noise masking or other measures to decrease neural artifact, TEP components before about 80 ms can be safely interpreted as stimulation location-specific responses to TMS, but components beyond this latency should be interpreted with caution due to high similarity in their topographical activity pattern.

Optimizing Hippocampal-Cortical Network Modulation via Repetitive Transcranial Magnetic Stimulation: A Dose-Finding Study Using the Continual Reassessment Method

OBJECTIVE

Repetitive transcranial magnetic stimulation (rTMS) can cause potentially useful changes in brain functional connectivity (FC), but the number of treatment sessions required is unknown. We applied the continual reassessment method (CRM), a Bayesian, adaptive, dose-finding procedure to a rTMS paradigm in an attempt to answer this question.

MATERIALS AND METHODS

The sample size was predetermined at 15 subjects and the cohort size was set with three individuals (i.e., five total cohorts). In a series of consecutive daily sessions, we delivered rTMS to the left posterior parietal cortex and measured resting-state FC with fMRI in a predefined hippocampal network in the left hemisphere. The session number for each successive cohort was determined by the CRM algorithm. We set a response criterion of a 0.028 change in FC between the hippocampus and the parietal cortex, which was equal to the increase seen in 87.5% of participants in a previous study using five sessions.

RESULTS

A ≥criterion change was observed in 9 of 15 participants. The CRM indicated that greater than four sessions are required to produce the criterion change reliably in future studies.

CONCLUSIONS

The CRM can be adapted for rTMS dose finding when a reliable outcome measure, such as FC, is available. The minimum effective dose needed to produce a criterion increase in FC in our hippocampal network of interest at 87.5% efficacy was estimated to be greater than four sessions. This study is the first demonstration of a Bayesian, adaptive method to explore a rTMS parameter.

Microfluidic Genipin Deposition Technique for Extended Culture of Micropatterned Vascular Muscular Thin Films

The chronic nature of vascular disease progression requires the development of experimental techniques that simulate physiologic and pathologic vascular behaviors on disease-relevant time scales. Previously, microcontact printing has been used to fabricate two-dimensional functional arterial mimics through patterning of extracellular matrix protein as guidance cues for tissue organization. Vascular muscular thin films utilized these mimics to assess functional contractility. However, the microcontact printing fabrication technique used typically incorporates hydrophobic PDMS substrates. As the tissue turns over the underlying extracellular matrix, new proteins must undergo a conformational change or denaturing in order to expose hydrophobic amino acid residues to the hydrophobic PDMS surfaces for attachment, resulting in altered matrix protein bioactivity, delamination, and death of the tissues. Here, we present a microfluidic deposition technique for patterning of the crosslinker compound genipin. Genipin serves as an intermediary between patterned tissues and PDMS substrates, allowing cells to deposit newly-synthesized extracellular matrix protein onto a more hydrophilic surface and remain attached to the PDMS substrates. We also show that extracellular matrix proteins can be patterned directly onto deposited genipin, allowing dictation of engineered tissue structure. Tissues fabricated with this technique show high fidelity in both structural alignment and contractile function of vascular smooth muscle tissue in a vascular muscular thin film model. This technique can be extended using other cell types and provides the framework for future study of chronic tissue- and organ-level functionality.

Long-term vascular contractility assay using genipin-modified muscular thin films

Vascular disease is a leading cause of death globally and typically manifests chronically due to long-term maladaptive arterial growth and remodeling. To date, there is no in vitro technique for studying vascular function over relevant disease time courses that both mimics in vivo-like tissue structure and provides a simple readout of tissue stress. We aimed to extend tissue viability in our muscular thin film contractility assay by modifying the polydimethylsiloxane (PDMS) substrate with micropatterned genipin, allowing extracellular matrix turnover without cell loss. To achieve this, we developed a microfluidic delivery system to pattern genipin and extracellular matrix proteins on PDMS prior to cell seeding. Tissues constructed using this method showed improved viability and maintenance of in vivo-like lamellar structure. Functional contractility of tissues fabricated on genipin-modified substrates remained consistent throughout two weeks in culture. These results suggest that muscular thin films with genipin-modified PDMS substrates are a viable method for conducting functional studies of arterial growth and remodeling in vascular diseases.

Small-cell lung carcinoma: an analysis of 194 consecutive patients

The treatment of small-cell lung carcinoma (SCLC) requires the careful combination of chemotherapy and radiation therapy. To understand the factors involved in the outcome of these patients, the authors undertook a study of patients treated for limited stage SCLC. The charts of 194 consecutive patients treated at our facilities between 1986 and 1994 were reviewed. All patients underwent thoracic radiation therapy (TRT), 50% received prophylactic cranial irradiation (PCI), and all but one received chemotherapy. The probability of survival at 5 years was 14%, and the disease-free survival (DFS) was 17%. Patients receiving a combination of platinum and etoposide (PE) and Cytoxan (Bristol-Myers, Evansville, IN, U.S.A.), Adriamycin (Adria Laboratories, Dublin, OH, U.S.A.), and Vincristine (Eli Lilly, Indianapolis, IN, U.S.A.) (CAV) experienced a DFS at 3 years of 31%, versus 14% for CAV only and 18% for PE only (p = 0.004). In a multivariate survival analysis, only PCI (p = 0.001), having received PE and CAV (p = 0.01), and response to treatment (p = 0.001) were significant. Radiation dose and field size did not influence outcome. The combination of PE and CAV chemotherapy produced the best results in our series. Unanswered questions regarding the optimal TRT dose, field size, and timing of TRT await the results of ongoing randomized trials.

Oral dolasetron mesylate in patients receiving moderately emetogenic platinum-containing chemotherapy. Oral Dolasetron Dose Response Study Group

PURPOSE

This double-blind, dose-response study was conducted to assess the safety and efficacy of four oral doses of dolasetron mesylate for preventing acute emesis in cancer patients receiving their first course of moderately emetogenic platinum-containing chemotherapy.

PATIENTS AND METHODS

Patients were randomized to receive a single oral dose of 25, 50, 100, or 200 mg dolasetron 30 minutes before receiving IV carboplatin (275-400 mg/m2)- or cisplatin (20-50 mg/m2)-containing chemotherapy, then monitored for nausea and vomiting for 24 hours.

RESULTS

Three hundred seven cancer patients from 32 sites completed the study. There was a statistically significant dose response across the four doses for complete response (no emetic episodes or rescue medication): 44.7%, 71.3%, 73.2%, and 82.5% for the 25, 50, 100, or 200 mg doses of dolasetron, respectively. Patients' nausea severity and patient satisfaction visual analogue scale scores also showed a statistically significant trend with dose. All doses of dolasetron were well tolerated. The most common adverse events were headache (17.6%) and dizziness (2.0%).

DISCUSSION

This study demonstrates the safety and antiemetic efficacy of oral dolasetron mesylate in patients receiving moderately emetogenic platinum-containing chemotherapy with the highest antiemetic activity observed at 200 mg.

Black widow spider bite in a child

An 8-year-old boy who was bitten by a black widow spider was seen in the emergency department twice, as well as by his private family physician, within a 24-hour period of time before being admitted to the hospital. This patient should have been observed for a longer period of time in the emergency department or admitted to the hospital on the day of presentation for observation with conservative management. The current literature is reviewed with special emphasis on the pediatric patient, and management guidelines are recommended.

Low doses of prophylactic cranial irradiation effective in limited stage small cell carcinoma of the lung

PURPOSE

Prophylactic cranial irradiation (PCI) for the prevention of brain metastasis in small cell lung cancer remains controversial, both in terms of efficacy and the optimal dose-fractionation scheme. We performed this study to evaluate the efficacy of PCI at low doses.

METHODS AND MATERIALS

One hundred and ninety-seven patients were referred to our institution for treatment of limited stage small cell carcinoma of the lung between June 1986 and December 1992. Follow-up ranged from 1.1 to 89.8 months, with a mean of 19 months. Eighty-five patients received PCI.

RESULTS

Patients receiving PCI exhibited brain failure in 15%, while 38% of untreated patients developed metastases. This degree of prophylaxis was achieved with a median total dose of 25.20 Gy and a median fraction size of 1.80 Gy. At these doses, acute and late complications were minimal. Patients receiving PCI had significantly better 1-year and 2-year overall survivals (68% and 46% vs. 33% and 13%). However, patients with a complete response (CR) to chemotherapy and better Karnofsky performance status (KPS) were overrepresented in the PCI group. In an attempt to compare similar patients in both groups (PCI vs. no PCI), only patients with KPS > or = 80, CR or near-CR to chemotherapy, and treatment with attempt to cure, were compared. In this good prognostic group, survival was still better in the PCI group (p = 0.0018).

CONCLUSION

In this patient population, relatively low doses of PCI have accomplished a significant reduction in the incidence of brain metastasis with little toxicity. Whether such treatment truly improves survival awaits the results of additional prospective randomized trials.

Chemotherapy of intermediate- and high-grade non-Hodgkin's lymphomas with a high-dose doxorubicin-containing regimen

Forty-seven previously untreated patients with intermediate- or high-grade non-Hodgkin's lymphoma were treated with four courses of a regimen that consisted of high-dose (120 mg/m2) Adriamycin (doxorubicin; Adria Laboratories, Columbus, OH), vincristine (2 mg), cytarabine (3 gm/m2), and dexamethasone (50 mg intravenously [IV] on day 1 and 20 mg/day orally on days 2 to 5) (AVAD), which was administered every 3 to 4 weeks. The median age of the patients was 58 years; 72% were Ann Arbor stage IV, 49% had "B" symptoms, 62% had masses larger than 7 cm, 40% had masses at least 10 cm in diameter, and 49% had serum lactate dehydrogenase (LDH) greater than 250 U/L. Overall, 72% of the patients (89% of diffuse large-cell lymphoma [DLCL] patients) attained complete (CR) or probable complete responses (PCR), and relapses occurred in 32%. There were no episodes of clinical congestive heart failure, but one patient developed recurrent ventricular arrhythmias. Fever during neutropenia occurred with 65% of treatment courses. Three deaths were attributed primarily to complications of therapy. The lymphoma-free survival of all entered patients is 51% (24 of 47), with a follow-up of 30 to 67 months (median, 58 months). These results confirm that high CR/PCR and long-term survival rates can be achieved in patients with aggressive histologies of non-Hodgkin's lymphomas, even in groups with poor prognostic factors, using high-dose anthracycline-containing chemotherapy regimens delivered over a short period of time. However, the apparently higher relapse rate in comparison to our previous study leads us to speculate that consolidation with noncross-resistant agents may be helpful in increasing even further the cure rate in this group of patients.

Differing modulation of protein kinase C by bryostatin 1 and phorbol esters in JB6 mouse epidermal cells

Bryostatin 1 (Bryo), a macrocyclic lactone, stimulates some but not all of the biologic effects which are induced by phorbol esters (PEs). In vitro, it competes with PEs for binding to whole cells and activates the calcium/phospholipid-dependent protein kinase, PK-C. To examine whether Bryo, like PEs, is able to stimulate the nonadherent growth of cells, we used the mouse epidermal cell line JB6, which is stimulated by PEs to grow in soft agar. Like PEs, Bryo stimulates both the adherent and nonadherent growth of these cells, but Bryo (0.001-1 microM) is less active than equivalent concentrations of PEs. To attempt to explain the biologic differences between these two agents, we examined the modulation of PK-C by both PEs and Bryo. In a phosphotransferase assay using partially purified PK-C from JB6 cells, Bryo (1-0.001 microM) stimulated less phosphorylation of histone substrate than did PMA. Also, when whole cells were treated with equal concentrations of Bryo or PMA, Bryo stimulated a decreased loss of PK-C from the cytosol. Using purified isozymes of PK-C from rat brain, Bryo demonstrated identical competition to PMA for binding to forms alpha and gamma but decreased binding to form beta. Hydroxylapatite chromatography of JB6 cytosol demonstrated that these cells contain largely peak 2, or beta-PK-C. Although Bryo more weakly activates PK-C from JB6 cells, prolonged exposure of JB6 cells to either 1.0 or 0.01 microM Bryo caused a more rapid loss of immunologically detectable PK-C than did similar concentrations of PEs. We conclude that Bryo is capable of stimulating both the nonadherent and the adherent growth of JB6 cells in a similar fashion to phorbol esters. The differences in biologic effects of Bryo and PMA may be partially explained by Bryo's modulation of PK-C.