Reshaping cortical activity with subthalamic stimulation in Parkinson's disease during finger tapping and gait mapped by near infrared spectroscopy

Exploration of motor cortex activity is essential to understanding the pathophysiology in Parkinson's Disease (PD), but only simple motor tasks can be investigated using a fMRI or PET. We aim to investigate the cortical activity of PD patients during a complex motor task (gait) to verify the impact of deep brain stimulation in the subthalamic nucleus (DBS-STN) by using Near-Infrared-Spectroscopy (NIRS). NIRS is a neuroimaging method of brain cortical activity using low-energy optical radiation to detect local changes in (de)oxyhemoglobin concentration. We used a multichannel portable NIRS during finger tapping (FT) and gait. To determine the signal activity, our methodology consisted of a pre-processing phase for the raw signal, followed by statistical analysis based on a general linear model. Processed recordings from 9 patients were statistically compared between the on and off states of DBS-STN. DBS-STN led to an increased activity in the contralateral motor cortex areas during FT. During gait, we observed a concentration of activity towards the cortex central area in the "stimulation-on" state. Our study shows how NIRS can be used to detect functional changes in the cortex of patients with PD with DBS-STN and indicates its future use for applications unsuited for PET and a fMRI

European LeukemiaNet laboratory recommendations for the diagnosis and management of chronic myeloid leukemia

From the laboratory perspective, effective management of patients with chronic myeloid leukemia (CML) requires accurate diagnosis, assessment of prognostic markers, sequential assessment of levels of residual disease and investigation of possible reasons for resistance, relapse or progression. Our scientific and clinical knowledge underpinning these requirements continues to evolve, as do laboratory methods and technologies. The European LeukemiaNet convened an expert panel to critically consider the current status of genetic laboratory approaches to help diagnose and manage CML patients. Our recommendations focus on current best practice and highlight the strengths and pitfalls of commonly used laboratory tests

DYNAMICS OF EXPANSION OF TYROSINE KINASE INHIBITOR-RESISTANT MUTANTS AS ASSESSED BY DEEP SEQUENCING OF THE BCR-ABL KINASE DOMAIN: IMPLICATIONS FOR ROUTINE MUTATION TESTING

Background: In Philadelphia-positive (Ph+) acute lymphoblastic leukemia (ALL) patients (pts), efficacy of tyrosine kinase inhibitor (TKI)-based therapies is often compromised by selection of resistant mutations in the BCR-ABL kinase domain (KD). Currently, the gold standard for BCR-ABL KD mutation screen- ing is conventional Sanger sequencing (SS). However, more sensitive approaches are desirable to allow more timely and rational therapeutic intervention. Aims: A Deep sequencing (DS) strategy based on the Roche 454 next-generation sequencing technology was set up in order to: study the dynamics of expansion of different types of BCR-ABL KD mutations in Ph+ ALL patients developing resistance to TKI-based therapies; test the ability of DS to highlight emerging clones harboring TKI-resistant mutations. Methods: 29 Ph+ ALL pts who had developed resistance to TKI-based (imatinib, dasatinib, nilotinib) therapies were selected for this retrospective analysis. All the pts were known to have developed TKI-resistant BCR-ABL mutations on treatment, as assessed by SS. To reconstruct the dynamics of mutation emergence, longitudinal re-analysis of samples from relapse backwards (n=97; 1-3 months sampling interval) was performed on a Roche GS Junior instru- ment. DS runs were designed so as to enable high sensitivity mutation calling (minimum target sequence coverage 4,000 reads). However, to minimize the likelihood of false positive results, data were analyzed filtering out all variants with <1% abundance. Results: DS could successfully detect all the mutations (n=85) previously identified by SS (>15% abundance). In addition, DS revealed that both those samples that had been scored as apparently wild-type by SS and those samples already known to harbor mutations as assessed by SS might be carrying one or more ‘lower level’ mutations (<15% abundance). In the latter cases, clonal analysis showed complex textures with the same mutation alone and also in combination with other(s) (‘compound’ mutations) in distinct subclones. Some lower level mutations were silent or apparently irrelevant from a clinical standpoint (passenger mutations?). In more than half of the cases, however, known TKI-resistant variants could be recognized that corresponded either to ‘withdrawing’ mutants not (yet) entirely de-selected by the switch in TKI or to outgrowing mutations anticipating an imminent relapse. Lower level mutations were confirmed with independent methods (ASO-PCR, RFLP). Notably, in 16/29 (55%) pts with molecularly detectable disease but not yet evidence of cytogenetic or hematologic relapse, DS could identify emerging mutations 1 to 3 months before they became detectable by SS. In the remaining 13 pts, however, outgrowth of the TKI-resistant mutation (T315I=7, Y253H=2, E255K=2, E255V=1 and F317L=1) was so rapid that not even a strict monthly monitoring could have allowed to pick them up before they became dominant. Summary / Conclusion: Now that multiple options are available, BCR-ABL KD mutation monitoring is a precious tool to maximize the efficacy of TKI-based regimens as induction or salvage therapy of Ph+ ALL. DS proved as reliable as SS for the detection of mutations with >15% abundance. As a key advantage, DS added precious quantitative and qualitative information on the full repertoire of mutated populations, that SS underestimated in more than half of the samples analyzed. TKI-resistant mutations leading to patient relapse were not necessarily preexisting at diagnosis or at the time of switchover to another TKI, underlining the importance of regular monitoring of pts. Although the majority of mutations were found to arise and take over very rapidly, a monthly monitoring by our DS approach would have allowed to identify them earlier than SS actually did - and well in advance of clinical relapse - in half of the pts. DS technologies would enable higher sensitivity mutation calling: further studies are warranted to determine the optimal lower detection limit to aim to in order to exclude both transient mutant subclones that will never take over and sequencing errors

Unraveling the complexity of tyrosine kinase inhibitor-resistant populations by ultra-deep sequencing of the BCR-ABL kinase domain

In chronic myeloid leukemia and Philadelphia chromosome-positive acute lymphoblastic leukemia, tyrosine kinase inhibitor (TKI) therapy may select for drug-resistant BCR-ABL mutants. We used an ultra-deep sequencing (UDS) approach to resolve qualitatively and quantitatively the complexity of mutated populations surviving TKIs and to investigate their clonal structure and evolution over time in relation to therapeutic intervention. To this purpose, we performed a longitudinal analysis of 106 samples from 33 patients who had received sequential treatment with multiple TKIs and had experienced sequential relapses accompanied by selection of 1 or more TKI-resistant mutations. We found that conventional Sanger sequencing had misclassified or underestimated BCR-ABL mutation status in 55% of the samples, where mutations with 1% to 15% abundance were detected. A complex clonal texture was uncovered by clonal analysis of samples harboring multiple mutations and up to 13 different mutated populations were identified. The landscape of these mutated populations was found to be highly dynamic. The high degree of complexity uncovered by UDS indicates that conventional Sanger sequencing might be an inadequate tool to assess BCR-ABL kinase domain mutation status, which currently represents an important component of the therapeutic decision algorithms. Further evaluation of the clinical usefulness of UDS-based approaches is warranted

How Do Microbial Pathogens Make CENs?

This article does not have an abstract

Outcomes of Patients With Hypertrophic Obstructive Cardiomyopathy and Pacemaker Implanted After Alcohol Septal Ablation

Background: Atrioventricular block is a frequent major complication after alcohol septal ablation (ASA). Objectives: The aim of this study was to evaluate the outcomes of patients with implanted permanent pacemaker (PPM) related to a high-grade atrioventricular block after ASA for hypertrophic obstructive cardiomyopathy. Methods: We used a multinational registry (the Euro-ASA registry) to evaluate the outcome of patients with PPM after ASA. Results: A total of 1,814 patients were enrolled and followed up for 5.0 ± 4.3 years (median = 4.0 years). A total of 170 (9.4%) patients underwent PPM implantation during the first 30 days after ASA. Using propensity score matching, 139 pairs (n = 278) constituted the matched PPM and non-PPM groups. Between the matched groups, there were no long-term differences in New York Heart Association functional class (1.5 ± 0.7 vs 1.5 ± 0.9, P = 0.99) and survival (log-rank P = 0.47). Patients in the matched PPM group had lower long-term left ventricular (LV) outflow gradient (12 ± 12 mm Hg vs 17 ± 19 mm Hg, P < 0.01), more pronounced LV outflow gradient decrease (81% ± 17% vs 72% ± 35%, P < 0.01), and lower LV ejection fraction (64% ± 8% vs 66% ± 8%, P = 0.02) and were less likely to undergo reintervention (re-ASA or myectomy) (log-rank P = 0.02). Conclusions: Patients with hypertrophic obstructive cardiomyopathy treated with ASA have a 9% probability of PPM implantation within 30 days after ASA. In long-term follow-up, patients with PPM had similar long-term survival and New York Heart Association functional class but lower LV outflow gradient, a more pronounced LV outflow gradient decrease, a lower LV ejection fraction, and a lower likelihood of reintervention compared with patients without PPM. © 2022 American College of Cardiology Foundatio

Small chromosomes among Danish Candida glabrata isolates originated through different mechanisms

We analyzed 192 strains of the pathogenic yeast Candida glabrata from patients, mainly suffering from systemic infection, at Danish hospitals during 1985-1999. Our analysis showed that these strains were closely related but exhibited large karyotype polymorphism. Nine strains contained small chromosomes, which were smaller than 0.5 Mb. Regarding the year, patient and hospital, these C. glabrata strains had independent origin and the analyzed small chromosomes were structurally not related to each other (i.e. they contained different sets of genes). We suggest that at least two mechanisms could participate in their origin: (i) through a segmental duplication which covered the centromeric region, or (ii) by a translocation event moving a larger chromosome arm to another chromosome that leaves the centromere part with the shorter arm. The first type of small chromosomes carrying duplicated genes exhibited mitotic instability, while the second type, which contained the corresponding genes in only one copy in the genome, was mitotically stable. Apparently, in patients C. glabrata chromosomes are frequently reshuffled resulting in new genetic configurations, including appearance of small chromosomes, and some of these resulting "mutant" strains can have increased fitness in a certain patient "environment"