Venous invasion detectable only by elastic stain shows weak prognostic value in colon cancer

AIMS

Large venous invasion (VI) is prognostically significant in colon cancer. The increased use of elastic stains by pathologists results in higher VI detection rates compared to routine stains alone. This study assesses the prognostic value of VI detected by elastic versus routine stains.

METHODS AND RESULTS

Colon cancers resected between 2014 and 2017 underwent pathology slide review for VI. Cases without VI on routine stain were stained by elastic trichrome and re-examined. Demographic, clinical, pathological and outcome data were gathered by retrospective review. Kaplan-Meier curves with log-rank tests were performed for survival categorised by VI status. Cox regression was performed for multivariate analysis. Of 277 cases, 97 (35%) showed VI by routine stain alone, with an additional 58 (21%) discovered by subsequent elastic stains. Thus, elastic trichrome increased VI detection by 60%. However, only VI detected by routine stain showed worse overall survival (P < 0.001). VI detected by elastic stain only was not prognostically different from cases without VI (P = 0.428). For stage 2 cancers, VI was not prognostically significant regardless of method of detection. For stage 3 cases, only VI detected by routine stain was prognostic for overall survival (P = 0.002) with a hazard ratio of 4.04 by multivariate regression (P = 0.028).

CONCLUSIONS

VI detectable only by elastic stains do not show prognostic significance for survival in colon cancer. For pathologists with high baseline VI detections rates on routine stain, reflexive use of elastic stain may be of limited value.

Detecting Encrypted and Unencrypted Network Data Using Entropy Analysis and Confidence Intervals

The detection of clear and encrypted data that are transported through computer networks is of particular importance both for protecting the data and the users to whom they belong and to whom they are intended, as well as the networks through which they are transmitted. The proposed method consists of an algorithm that classifies the data it receives by testing the belongingness of their standard deviation values to established confidence intervals. Following the evaluation of the algorithm, an accuracy of 94.73% was obtained and it appears that the results can be used with certainty in subsequent analyses of the data detection.

Abnormal cerebellar processing of the neck proprioceptive information drives dysfunctions in cervical dystonia

The cerebellum can influence the responsiveness of the primary motor cortex (M1) to undergo spike timing-dependent plastic changes through a complex mechanism involving multiple relays in the cerebello-thalamo-cortical pathway. Previous TMS studies showed that cerebellar cortex excitation can block the increase in M1 excitability induced by a paired-associative stimulation (PAS), while cerebellar cortex inhibition would enhance it. Since cerebellum is known to be affected in many types of dystonia, this bidirectional modulation was assessed in 22 patients with cervical dystonia and 23 healthy controls. Exactly opposite effects were found in patients: cerebellar inhibition suppressed the effects of PAS, while cerebellar excitation enhanced them. Another experiment comparing healthy subjects maintaining the head straight with subjects maintaining the head turned as the patients found that turning the head is enough to invert the cerebellar modulation of M1 plasticity. A third control experiment in healthy subjects showed that proprioceptive perturbation of the sterno-cleido-mastoid muscle had the same effects as turning the head. We discuss these finding in the light of the recent model of a mesencephalic head integrator. We also suggest that abnormal cerebellar processing of the neck proprioceptive information drives dysfunctions of the integrator in cervical dystonia.

The reliability of commonly used electrophysiology measures

BACKGROUND

Electrophysiological measures can help understand brain function both in healthy individuals and in the context of a disease. Given the amount of information that can be extracted from these measures and their frequent use, it is essential to know more about their inherent reliability.

OBJECTIVE/HYPOTHESIS

To understand the reliability of electrophysiology measures in healthy individuals. We hypothesized that measures of threshold and latency would be the most reliable and least susceptible to methodological differences between study sites.

METHODS

Somatosensory evoked potentials from 112 control participants; long-latency reflexes, transcranial magnetic stimulation with resting and active motor thresholds, motor evoked potential latencies, input/output curves, and short-latency sensory afferent inhibition and facilitation from 84 controls were collected at 3 visits over 24 months at 4 Track-On HD study sites. Reliability was assessed using intra-class correlation coefficients for absolute agreement, and the effects of reliability on statistical power are demonstrated for different sample sizes and study designs.

RESULTS

Measures quantifying latencies, thresholds, and evoked responses at high stimulator intensities had the highest reliability, and required the smallest sample sizes to adequately power a study. Very few between-site differences were detected.

CONCLUSIONS

Reliability and susceptibility to between-site differences should be evaluated for electrophysiological measures before including them in study designs. Levels of reliability vary substantially across electrophysiological measures, though there are few between-site differences. To address this, reliability should be used in conjunction with theoretical calculations to inform sample size and ensure studies are adequately powered to detect true change in measures of interest.

Activation of the LMO2 oncogene through a somatically acquired neomorphic promoter in T-cell acute lymphoblastic leukemia

Somatic mutations within noncoding genomic regions that aberrantly activate oncogenes have remained poorly characterized. Here we describe recurrent activating intronic mutations of LMO2, a prominent oncogene in T-cell acute lymphoblastic leukemia (T-ALL). Heterozygous mutations were identified in PF-382 and DU.528 T-ALL cell lines in addition to 3.7% of pediatric (6 of 160) and 5.5% of adult (9 of 163) T-ALL patient samples. The majority of indels harbor putative de novo MYB, ETS1, or RUNX1 consensus binding sites. Analysis of 5'-capped RNA transcripts in mutant cell lines identified the usage of an intermediate promoter site, with consequential monoallelic LMO2 overexpression. CRISPR/Cas9-mediated disruption of the mutant allele in PF-382 cells markedly downregulated LMO2 expression, establishing clear causality between the mutation and oncogene dysregulation. Furthermore, the spectrum of CRISPR/Cas9-derived mutations provides important insights into the interconnected contributions of functional transcription factor binding. Finally, these mutations occur in the same intron as retroviral integration sites in gene therapy-induced T-ALL, suggesting that such events occur at preferential sites in the noncoding genome.

Cerebellar processing of sensory inputs primes motor cortex plasticity

Plasticity of the human primary motor cortex (M1) has a critical role in motor control and learning. The cerebellum facilitates these functions using sensory feedback. We investigated whether cerebellar processing of sensory afferent information influences the plasticity of the primary motor cortex (M1). Theta-burst stimulation protocols (TBS), both excitatory and inhibitory, were used to modulate the excitability of the posterior cerebellar cortex and to condition an ongoing M1 plasticity. M1 plasticity was subsequently induced in 2 different ways: by paired associative stimulation (PAS) involving sensory processing and TBS that exclusively involves intracortical circuits of M1. Cerebellar excitation attenuated the PAS-induced M1 plasticity, whereas cerebellar inhibition enhanced and prolonged it. Furthermore, cerebellar inhibition abolished the topography-specific response of PAS-induced M1 plasticity, with the effects spreading to adjacent motor maps. Conversely, cerebellar excitation had no effect on the TBS-induced M1 plasticity. This demonstrates the key role of the cerebellum in priming M1 plasticity, and we propose that it is likely to occur at the thalamic or olivo-dentate nuclear level by influencing the sensory processing. We suggest that such a cerebellar priming of M1 plasticity could shape the impending motor command by favoring or inhibiting the recruitment of several muscle representations.

Long-lasting inhibition of cerebellar output

OBJECTIVE

The cerebellar influence on the motor cortex output is exerted mostly though the cerebellothalamocortical pathway (CTC). One way to explore this pathway is by the means of transcranial magnetic stimulation (TMS). A single-pulse conditioning magnetic stimulation delivered over the lateral cerebellum was shown to diminish the excitability of the contralateral motor cortex 5 milliseconds later (cerebellocortical inhibition [CBI]), most likely through transynaptic activation of cerebellar Purkinje cells, which in turn inhibit the tonic activity of the CTC. Repetitive TMS (rTMS) delivered over the lateral cerebellum was shown to induce a long-lasting change of the cortical excitability, as well, but the mechanism and time course of this effect are still debated.

METHODS

We tested the time course of the effects of rTMS on the CBI in five paradigms: (1) 1 Hz rTMS, (2) continuous theta burst stimulation (cTBS), and (3) intermittent TBS (iTBS) over the right cerebellum, (4) 1 Hz rTMS over the cervical nerve roots, and (5) 1 Hz rTMS over the left cerebellum. Surface electromyography was recorded from the right first dorsal interosseous (FDI) and adductor digiti minimi. A double-cone coil was used for single-pulse cerebellar stimulation, whereas a figure-of-eight coil was used for the rTMS. The stimulus intensity was set at 90% of the M1 resting motor threshold for 1 Hz rTMS, and at 80% of the M1 active motor threshold for TBS. Both types of cerebellar stimulation were performed under magnetic resonance image (MRI)-guided neuronavigation centered over the right VIII B lobule, and stimulation intensities were adjusted for cerebellar cortex depth. A figure-of-eight coil was used for left motor cortex stimulation.

RESULTS

There was significant CBI suppression to the left motor cortex up to 30 minutes after the 900 stimuli of 1 Hz rTMS over either cerebellar hemisphere, and after 600 stimuli of cTBS over the right cerebellum, but not after 600 stimuli of iTBS over the right cerebellum, or after 900 of 1 Hz rTMS stimuli delivered over the cervical nerve roots. The 1 Hz rTMS over the left cerebellum significantly reduced the CBI in the right FDI 10 minutes after the end of the intervention. The amplitudes of the unconditioned cortical motor-evoked potentials were not significantly changed.

CONCLUSIONS

Our findings suggest that repetitive cerebellar stimulation operate at a cerebellar level, rather then at a cortical level.

Factors influencing the relation between corticospinal output and muscle force during voluntary contractions

The mechanisms by which voluntary forces of different strengths are produced in human muscles are not clear. We studied the relation between force and surface electromyography (sEMG) variables over a wide range of voluntary contraction strengths of biceps brachii (BIC) and abductor digiti minimi (ADM). The relation between force and motor evoked potentials (MEPs) to transcranial magnetic stimulation of motor cortex was also assessed. The root mean square of sEMG and median frequency (Mf) of the sEMG power spectrum as well as the MEP area of ADM and BIC were calculated up to the maximum voluntary contraction (MVC). The root mean square of ADM and BIC increased with increasing force levels up to the MVC. The Mf of BIC increased with force levels up to 70% MVC after which it rapidly declined. The Mf of ADM peaked at 40% MVC to slowly decline thereafter. The MEP changes with force were similar to Mf changes. Thus, corticospinal output, as tested by the Mf and MEPs, does not parallel force increments across the contraction range. This decline, which is contingent on the relative contribution of motor unit recruitment and rate coding to force production in each muscle, may depend on reduced motoneurone responsiveness at high firing rates. We suggest that, under controlled conditions, the frequency content of the sEMG signal may be taken to indicate motor unit recruitment range. This information may improve the utility of the Mf to enable evaluation of voluntary activation under different conditions.

Changes in coordination of postural control during dynamic stance in chronic low back pain patients

The human postural system operates on the basis of integrated information from three independent sources: vestibular, visual and somatosensory. It is conceivable that a derangement of any of these systems will influence the overall output of the postural system. The peripheral proprioceptive system or the central processing of proprioceptive information may be altered in chronic low back pain (CLBP). We therefore investigated whether patients with CLBP exhibited an altered postural control during quiet standing. Dynamic posturography was performed by 12 CLBP patients and 12 age-matched controls. Subject's task was to stand quietly on a computer-controlled movable platform under six sensory conditions that altered the available visual and proprioceptive information. While the control of balance was comparable between the two groups across stabilized support surface conditions (1-3), CLBP patients oscillated much more than controls in the anterior-posterior (AP) direction in platform sway-referenced conditions (4-6). Control experiments ruled out that increased sway was due to pain interference. In CLBP patients, postural stability under challenging conditions is maintained by an increased sway in AP direction. This change in postural strategy may underlie a dysfunction of the peripheral proprioceptive system or the central integration of proprioceptive information.

Cortico-motoneuronal output to intrinsic hand muscles is differentially influenced by static changes in shoulder positions

We investigated whether shoulder position influenced the recruitment properties of the abductor digiti minimi muscle (ADM) and first dorsal interosseous muscle (FDI). ADM and FDI motor evoked potentials (MEPs) in response to transcranial magnetic stimulation (TMS) were obtained in seven healthy volunteers at two different static positions of the shoulder joint (30 degrees adduction vs 30 degrees abduction) while the arm was passively supported at shoulder level (90 degrees in the horizontal plane) and the elbow joint was fixed at 90 degrees . ADM and FDI voluntary activity was also examined during (1) externally paced finger abductions at 2 Hz in the two different shoulder positions (EMG(ADM) and EMG(FDI) was back-averaged time-locked to the end of finger abduction) and (2) maximal voluntary abduction of the little finger and the index finger. Maximal EMG power and force were analysed in the two shoulder positions. H-reflexes from ADM and FDI were also obtained in two subjects. The ADM stimulus-response curve to TMS showed that the slope and plateau level were significantly reduced with the shoulder at 30 degrees abduction. In contrast, the FDI stimulus-response curve to TMS was not influenced by shoulder position. The back-averaged EMG(ADM) showed a significant decrease in peak amplitude and area with the shoulder at 30 degrees abduction, while no change in EMG(FDI) was observed under the same condition. Similarly, maximal EMG(ADM) and force exertion by the little finger were significantly reduced with the shoulder at 30 degrees abduction, while no such effect was observed for FDI. ADM H-reflex, but not FDI, was also decreased with shoulder abduction. These results indicate that the corticospinal pathway to ADM is less accessible to TMS and to voluntary command when the shoulder is placed at 30 degrees abduction. In contrast, activation of FDI, whether by TMS or by volition, is not influenced by shoulder position. This finding suggests that there are differences in the corticospinal innervation to ADM and FDI, possibly due to the different role of these muscles in hand function.