Predictors of the usefulness of mirogabalin for neuropathic pain: a single-institution retrospective study

Mirogabalin is a novel, preferentially selective α2δ-1 ligand to treat neuropathic pain. However, this agent is not always effective for patients with neuropathic pain. We therefore attempted to identify factors that could predict the efficacy of mirogabalin. The study comprised 133 patients given mirogabalin for alleviation of neuropathic pain between April and November 2019 at our hospital. Variables were extracted from medical records for regression analysis of factors associated to alleviation of neuropathic pain. We evaluated the effect of mirogabalin at two weeks after administration. Groups were categorized according to degree of improvement: poor, effective, or very effective. Multivariate ordered logistic regression analysis was conducted to identify predictors for the usefulness of mirogabalin. Threshold measures were analysed using receiver operating characteristic (ROC) curves. Maintenance dose [odds ratio (OR) = 0.90; 95% confidence interval (CI) = 0.84-0.98; P = 0.01], concomitant use of opioids (OR = 0.26, 95% CI = 0.08-0.83; P = 0.023) and Neurotropin^® (NTP) (OR = 4.78, 95% CI =1.04-21.93; P = 0.044) were factors significantly correlated to the effect of mirogabalin. ROC curve analysis of the effective group indicated a threshold maintenance dose of≤ 20 mg/day (area under the curve [AUC] = 0.53). In conclusion, maintenance dose (≤ 20 mg), concomitant use of opioids and NTP were identified as predictors for the utility of mirogabalin.

THU0568 EFFECTIVENESS OF FOOT ORTHOSIS TO PROMOTE PHYSICAL ACTIVITY FOR PATIENTS WITH CONCURRENT RHEUMATOID ARTHRITIS AND SARCOPENIA

Background:

Sarcopenia is a progressive systemic skeletal muscle disorder associated with an increased likelihood of adverse outcomes including physical disability, falls, and mortality. The muscle mass of patients with rheumatoid arthritis (RA) is lower than that of age-matched healthy individuals, and a high prevalence rate of sarcopenia has been reported1). In particular, foot deformities may increase the prevalence rate of sarcopenia because of inactivity due to foot pain on walking. Treatment with a foot orthosis (FO) can reportedly reduce pain2); however, whether a FO can resolve inactivity and sarcopenia is unclear.

Objectives:

To elucidate the effectiveness of a FO on physical activity and sarcopenia in patients with RA.

Methods:

Thirty patients with RA with foot deformities were enrolled from April 2017 to December 2019. Sarcopenia was diagnosed using the algorithm of the European Working Group on Sarcopenia in Older People, and the cut-off values of the Asian Working Group for Sarcopenia were applied. We also collected the clinical variables of patients with concurrent RA and sarcopenia who continued to use a FO for 6 months. The primary outcome was physical activity determined by the International Physical Activity Questionnaire. The secondary outcomes were foot pain measured with a visual analog scale; activities of daily living (ADL) measured with the Health Assessment Questionnaire; and body mass index, body fat percentage, and the skeletal muscle mass index measured with a body composition device. The clinical variables were compared between baseline and 6 months after continuous treatment with a FO.

Results:

The prevalence rate of sarcopenia was 76.6% (23/30), and nine patients with RA continued to use the FO for 6 months. Table 1 shows outcomes at baseline and after 6 months of treatment with a FO. The only clinical variable that showed a significant difference was foot pain. Physical activities, ADL, and body compositions were maintained after 6 months.

Table 1.

Outcomes of 6-month treatment with FO

Baseline6 monthsp valuePhysical activityIPAQWalking, MET-min/weekModerate, MET-min/weekVigorous, MET-min/week132 (66, 594)0 (0, 0)0 (0, 0)594 (396, 2376)0 (0, 0)0 (0, 0)0.071.000.32Foot painVAS score4.6 (3.1, 7.4)2.8 (1.1, 4.7)0.02ADLHAQ1.5 (1.1, 2.3)1.1 (0.9, 1.5)0.07Body compositionBMI, kg/m2BFP, %SMI, kg/m221.4 (20.7, 22.7)31.1 (24.2, 37.6)5.2 (4.8, 5.3)20.7 (19.3, 22.1)32.9 (26.3, 36.5)5.2 (5.0, 5.2)0.890.820.61

IPAQ: International Physical Activity Questionnaire, VAS: visual analog scale, ADL: activities of daily living, HAQ: Health Assessment Questionnaire, BMI: body mass index, BFP: body fat percentage, SMI: skeletal muscle mass index

Data are presented as median (lower quartile, upper quartile)

Conclusion:

The prevalence rate of sarcopenia in patients with RA with foot deformities was much higher than previous reported1). However, 6 months of treatment with a FO not only reduced foot pain but also maintained physical activity and muscle mass. Physical therapy has recently been recommended for patients with inflammatory arthritis. physical activity and muscle mass of patients with RA and concurrent foot deformities may be increased by combining physical therapy with orthotic treatment.

References:

[1]Tada M, et al. Matrix metalloprotease 3 is associated with sarcopenia in rheumatoid arthritis - results from the CHIKARA study. Int J Rheum Dis. 2018; 21 (11): 1962-9.

[2]Hennessy K, et al. Custom foot orthoses for rheumatoid arthritis: A systematic review. Arthritis Care Res (Hoboken). 2012; 64 (3): 311-20.

Acknowledgments:

This work was supported by JSPS KAKENHI Grant Numbers JP19K11420.

Disclosure of Interests:

None declared

DOI: 10.1136/annrheumdis-2020-eular.3143

Remission induction, maintenance, and endoscopic outcome with oral 5-aminosalicylic acid in intestinal Behçet's disease

BACKGROUND AND AIM

Oral 5-aminosalicylic acid (5-ASA) is recommended for the therapy of mild to moderate intestinal Behçet's disease (BD). However, the induction remission efficacy and endoscopic outcomes of 5-ASA are unknown. We investigated remission induction at 8 weeks, endoscopic outcomes until 52 weeks, and event-free survival at 52 weeks in patients with intestinal BD treated with 5-ASA.

METHODS

Forty-one patients with intestinal BD were treated with oral 5-ASA. Clinical remission was evaluated with the Crohn's disease activity index (CDAI). The endoscopic response was evaluated using the modified global gastrointestinal endoscopic assessment scores. Rescue therapy-free survival and surgery-free survival at 52 weeks were estimated, and predictive factors for a clinical response at weeks 8 and 52 were identified.

RESULTS

Seven patients (17%) withdrew 5-ASA early (≤ 8 weeks) because of adverse events. At week 8, clinical efficacy could be accurately evaluated in 28 patients, and the response and remission rates were 61% and 57%, respectively, using the CDAI. Endoscopic evaluation was achieved in 17 patients up to 52 weeks, and the endoscopic response and remission rates were 71% and 35%, respectively. The probabilities of rescue therapy-free survival and surgery-free survival were 73% and 100%, respectively, at 52 weeks in all 41 patients. The predictive factors for therapeutic effectiveness at week 8 were a higher baseline C-reactive protein level and CDAI, but they were negative predictive factors for a 52-week response.

CONCLUSIONS

5-ASA is effective for clinical and endoscopic induction and maintaining a response in patients with mild to moderate intestinal BD.

Clinical application of radial magnetic resonance imaging for evaluation of rotator cuff tear

BACKGROUND

Magnetic resonance imaging is useful for evaluating the rotator cuff, but some tendinous insertions cannot be assessed using oblique sagittal, oblique coronal, and axial magnetic resonance (MR) images because of the presence of the partial volume effect.

HYPOTHESIS

The purpose of this study was to determine whether radial-slice MR images could reveal normal rotator cuff insertions and rotator cuff tears more clearly than conventional MR images.

PATIENTS AND METHODS

The study included 18 subjects with normal rotator cuffs and 30 with rotator cuff tears. MR images of rotator cuff insertions sliced into radial, oblique coronal, and axial sections were obtained. The extent to which normal rotator cuff insertions and rotator cuff tears were visualized in each of the three MR images was evaluated.

RESULTS

The top to posterior portions of the rotator cuff insertions from 0° to 120° could be visualized in the radial MR images. In comparison, the posterior portions of the rotator cuff insertions could not be visualized around 45° in both the oblique coronal and axial MR images.

DISCUSSION

These findings demonstrate that radial MR images are superior to the oblique coronal and axial MR images regarding their ability to accurately visualize rotator cuff insertions. Radial MR images also revealed greater detail around 45° in the posterior area of the rotator cuff tears than the oblique coronal and axial MR images. Radial MR images are particularly useful for visualizing clinically important posterosuperior rotator cuff tears.

LEVEL OF EVIDENCE

Level III - Diagnostic study.

Three cases of suspected sugammadex-induced hypersensitivity reactions

Neuromuscular blocking agents have been implicated in 60-70% of anaphylactic events associated with anaesthesia. We report two cases of probable hypersensitivity reaction to sugammadex and an additional suspected but less supported case of possible immune-mediated reaction or other adverse reaction. The patients were given a bolus of sugammadex 100 mg immediately before extubation. In all three patients, a possible allergic reaction was suspected within 4 min of sugammadex administration, but with different degrees of severity. Skin testing was positive in two of these patients. Hypersensitivity to sugammadex unaccompanied by cardiovascular or respiratory symptoms might be missed during the course of anaesthesia. Careful monitoring for possible allergic responses is required in patients who have received sugammadex.

Motor learning of hands with auditory cue in patients with Parkinson’s disease

In the present research, changes in motor cortex function were observed in relation to repetitive, voluntary thumb movement (training) in patients with Parkinson's disease (PD) and normal control subjects. Changes in the direction of thumb movement due to motor evoked potential (MEP) by transcranial magnetic stimulation (TMS), after motor training with and without rhythmic sound, were measured using a strain gauge for 12 patients with PD and 9 normal control subjects. PD patients who experienced the freezing phenomena showed poor change in direction of TMS-induced movement after self-paced movement; however, marked change in direction of TMS-induced movement was observed after training with auditory cue. PD patients who had not experienced the freezing phenomena showed positive effects with the auditory cue, producing similar results as the normal control subjects. Two routes for voluntary movement are available in the nervous system. The decreased function of basal ganglia due to PD impaired the route from the basal ganglia to the supplementary motor cortex. These data suggest that the route from sensory input to cerebellum to premotor cortex could compensate for the decreased function of the route via the basal ganglia to the premotor cortex. Once change in the motor cortex occurred, such change persisted even after the interruption of training. These phenomena suggest that motor memory can be stored in the motor cortex.

Nitric oxide synergistically potentiates interleukin-1 beta-induced increase of cyclooxygenase-2 mRNA levels, resulting in the facilitation of substance P release from primary afferent neurons: involvement of cGMP-independent mechanisms

We previously demonstrated that cultured rat dorsal root ganglion (DRG) cells respond to stimulation with interleukin-1 beta (IL-1 beta) by releasing substance P (SP), and this response is regulated via the cyclooxygenase (COX)-2 pathway. In this study, to ascertain the interaction between nitric oxide (NO) and prostaglandins in primary afferent neurons, we investigated the effect of NO on the IL-1 beta-induced release of SP in cultured DRG cells. An NO donor, S-nitroso-N-acetyl-DL-penicillamine (SNAP), did not in itself evoke SP release. However, it potentiated the IL-1 beta-induced release of SP. Similarly, while SNAP did not elicit the expression of COX-2 mRNA, it potentiated the expression induced by IL-1 beta in cultured DRG cells, and this potentiation was significantly suppressed by the NO scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (carboxy-PTIO). Moreover, SNAP also potentiated the expression of COX-2 protein induced by IL-1 beta in cultured DRG cells. The stimulatory effect of SNAP on the IL-1 beta-induced release of SP was completely inhibited on co-incubation with a selective COX-2 inhibitor, NS-398. 1H-[1,2,4]oxadiazolo[4,3-a]quinoxaline-1-one (ODQ), a potent inhibitor of soluble guanylate cyclase, did not suppress, and a membrane-permeable cGMP analogue, 8-Br-cGMP, did not mimic the stimulatory effects of SNAP in DRG cells. These results suggest that in cultured DRG cells, NO potentiates the IL-1 beta-induced increase in COX-2 expression via a soluble guanylate cyclase-cGMP-independent pathway, resulting in facilitation of SP release. The interaction between NO and COX in primary afferent neurons might contribute to the change in nociceptive perception in inflammatory hyperalgesia.

(1)H double-quantum filtered MR imaging of joints tissues: bound water specific imaging of tendons, ligaments and cartilage

The (1)H double-quantum filtered (DQF) NMR and DQF MRI is applied to the joint tissues of rabbits for selective visualization of tendons, menisci and articular cartilage. The (1)H DQF NMR selectively filters double-quantum coherence arising from the (1)H dipolar interaction of the "bound" water in these tissues. The double-quantum creation time dependency of the DQF signal intensity is determined by the molecular environment of the "bound" water. Therefore, each tissue has a unique creation time at which the DQF signal reaches its maximum intensity, tau(max) (Achilles tendon: 0.46 +/- 0.02 ms, patella: 0.55 +/- 0.8 ms, anterior cruciate ligament: 0.60 +/- 0.05 ms, meniscus: 0.78 +/- 0.02 ms, skin: 0.81 +/- 0.07 ms). We have presented the creation-time-contrasted DQF images of the meniscus, patella, foot, and knee joint. Compared with conventional T(2)*-weighted gradient-echo (GRE) MR images, tendons, ligaments, menisci, and articular cartilage were more clearly seen in the DQF MR images. All these tissues were distinctly discriminated from each other by their creation times. DQF MR images of foot and knee joints can selectively demonstrated tendons, ligaments, and cartilage, which make it easier to understand the complicated anatomic structure of joints. Because the DQF NMR signal intensity and tau(max) are sensitive to the order structure of the "bound" water, it might be possible to introduce the creation-time dependent-contrast of (1)H DQF MR images as a new tool for analyzing the changes in the ordered structure of the tissue.

Characteristics of proton NMR T(2) relaxation of water in the normal and regenerating tendon

The molecular behavior of water in normal and regenerating tendons was analyzed using the transverse relaxation time (T(2)) measured by spin-echo proton nuclear magnetic resonance ((1)H-NMR) spectroscopy at 2.34 T (25 degrees C). A section of the Achilles tendon was dissected from an anesthetized Japanese white rabbit, and its longitudinal axis was oriented at 0, 35, 54.7, 75, and 90 degrees to the static magnetic field. In the normal tendon, the T(2) relaxation of water presented biexponential relaxation and anisotropy in both the long T(2) (5.41 to 6.21 ms) and short T(2) (0.41 to 1.43 ms) components, in which the greatest values were obtained at 54.7 degrees. However, the range of the anisotropy was much narrower than we expected from the (1)H dipolar interaction of water bound to the collagen fibers in the tendon. The apparent fractions of water proton density also varied with orientation: the fraction of the longer T(2) components was at its maximum at 54.7 degrees. These results suggest that a simple two-compartment model could not be applicable to orientational dependency of the T(2) value of the tendon, and the well ordered water in the short T(2) relaxation component may show an elongated T(2) relaxation time that falls in the range of the long T(2) relaxation component at 54.7 degrees. This hypothesis can explain both the narrower range of the T(2) relaxation time and the orientational dependency on the apparent fraction of (1)H density. Regenerating processes of the Achilles tendon were followed for 18 weeks by analyzing the T(2) relaxation time. There is only a long T(2) relaxation time component (21.8 to 28.0 ms) up to 3 weeks after transection. Biexponential relaxation is revealed at 6 weeks and thereafter, whereby (i) the T(2) relaxation times become shorter, (ii) there is anisotropy in the short and long T(2) values, and (iii) the orientational dependency of the apparent fraction of water proton density becomes evident with maturation of the regenerating tendon. From these results, the (1)H T(2) relaxation time of water might be used to monitor the healing process of collagen structures of the tendon non-invasively.

Human corticospinal excitability evaluated with transcranial magnetic stimulation during different reaction time paradigms

The aim of this study was to evaluate corticospinal excitability of both hemispheres during the reaction time (RT) using transcranial magnetic stimulation (TMS). Nine right-handed subjects performed right and left thumb extensions in simple (SRT), choice (CRT) and go/no-go auditory RT paradigms. TMS, inducing motor-evoked potentials (MEPs) simultaneously in the extensor pollicis brevis muscles bilaterally, was applied at different latencies from the tone. For all paradigms, MEP amplitudes on the side of movement increased progressively in the 80-120 ms before EMG onset, while the resting side showed inhibition. The inhibition was significantly more pronounced for right than for left thumb movements. For the left SRT, significant facilitation occurred on the right after EMG onset. Initial bilateral facilitation occurred in SRT trials with slow RT. After no-go tones, bilateral inhibition occurred at a time corresponding to the mean RT to go tones. The timing of the corticospinal rise in excitability on the side of movement was independent of task difficulty and RT. This suggests that corticospinal activation is, to some extent, in series and not in parallel with stimulus processing and response selection. Corticospinal inhibition on the side not to be moved implies that suppression of movement is an active process. This inhibition is more efficient for right- than for left-side movements in right-handed subjects, possibly because of left hemispheric dominance for movement.

Interleukin-1beta induces substance P release from primary afferent neurons through the cyclooxygenase-2 system

Substance P (SP) is synthesized in the dorsal root ganglion (DRG) and released from primary afferent neurons to convey information regarding noxious stimuli. The effects of the proinflammatory cytokine interleukin-1 (IL-1) beta on the release of SP were investigated using primary cultured rat DRG cells. Recombinant mouse IL-1beta added to the cells at 0.1 ng/ml increased the SP-like immunoreactivity (SPLI) in the culture medium after incubation for 6 h by approximately 50% as compared with that of nontreated DRG cells. The effect of IL-1beta was Ca(2+)-dependent and significantly inhibited by 100 ng/ml IL-1 receptor-specific antagonist (IL-1r antagonist), cyclooxygenase (COX) inhibitors such as 0.1 mM aspirin, 1 microg/ml indomethacin, and 1 microM NS-398 (specific for COX-2), and 1 microM dexamethasone. Furthermore, a 1-h incubation with IL-1beta markedly increased the inducible COX-2 mRNA level, which was inhibited by an IL-1r antagonist and dexamethasone, whereas IL-1beta showed no effect on the level of constitutive COX-1 mRNA. These observations indicated that IL-1beta induced the release of SP from the DRG cells via specific IL-1 receptors, the mechanism of which might involve prostanoid systems produced by COX-2. This could be responsible for the hyperalgesic action with reference to inflammatory pain in the primary afferent neuron to spinal cord pathway.

1H double-quantum-filtered MR imaging as a new tool for assessment of healing of the ruptured Achilles tendon

1H double-quantum-filtered magnetic resonance imaging (DQF MRI) was applied to monitor the healing process of the Achilles tendons in rabbits after tenotomy. DQF MRI provides a new contrast, which is based on the non-zero average of the dipolar interaction caused by anisotropic motion of water molecules, determined mainly by their interaction with the ordered collagen fibers. Tissues are characterized by the dependence of their DQF signal on the DQ creation time, tau. With the use of DQF MRI, higher tissue contrast is obtained between tendon, bone, skin, and muscle. The tendons, which give weak signals in standard MRI techniques, are highlighted in the (1)H DQF image. The image changed dramatically during the healing process of the injured Achilles tendon. These changes matched the phases of the healing process. By using a tau-weighted contrast, the DQF images indicate the part of tendon that has not completely healed, even after the conventional MRI appeared normal. Magn Reson Med 42:884-889, 1999.

Subclinical syphilitic hepatitis, which was markedly worsened by a Jarisch-Herxheimer reaction

Early syphilitic hepatitis is uncommon and tends to be overlooked. However, the diagnosis of this disease is important, because appropriate treatment results in rapid resolution of the hepatitis. We report a case of subclinical early syphilitic hepatitis exaggerated by a Jarisch-Herxheimer reaction. This reaction helped to realize the diagnosis in this case.

Norepinephrine- and K+-induced Mn2+-dependent contractions and the dynamics of intracellular Mn2+ changes in dispersed smooth muscle cells from Ca2+-depleted Mn2+-loaded vas deferens of the guinea pig

The cellular mechanisms of norepinephrine (NE)-induced Mn2+-dependent contractions were investigated in dispersed smooth muscle cells from guinea pig vas deferens by characterizing the effects of NE and K+ on cell length observed by videotape microscopy and on intracellular Mn2+ and Ca2+ concentration ([Mn2+]i and [Ca2+]i) observed by confocal microscopy. Both stimulants induced slow sustained contraction in Ca2+-depleted, Mn2+-accumulated cells (Mn2+-loaded cells), whereas they induced biphasic contractions in normal cells that were neither Ca2+-depleted nor Mn2+-loaded. In both conditions, the number of cells responding to NE as well as the magnitude of NE-induced contractions increased in a dose-dependent manner. Contractions induced by K+ in Mn2+-loaded strip preparations were markedly smaller than those induced by NE. Although individual K+-induced contractions in responsive Mn2+-loaded cells were as large as those induced by NE, a much smaller percentage of Mn2+-loaded cells was responsive to K+ than to NE. These results are consistent with the idea that the contractions of strip preparations may reflect the magnitude of the contractions of individual cells as well as the percentage of responsive cells in the preparations. Inconsistent with the contractions, the [Mn2+]i rise induced by K+ was larger than that induced by NE, and the percentage of cells responsive to K+ was larger than that responsive to NE. These results suggest that NE may increase the Mn2+ sensitivity of contractile elements.

[A case of acute multifocal motor neuropathy with conduction block after Campylobacter jejuni enteritis]

The patient was a 25-year-old male with acute multifocal motor neuropathy with conduction block (MMNCB) after Campylobacter jejuni enteritis. After having suffered from diarrhea for 3 days, he rapidly developed asymmetrical distal-dominant muscle weakness in all extremities. Sensory disturbance was unremarkable except for slight disturbance in deep sensation. Deep tendon reflexes were normal throughout the course of present illness. CSF analysis revealed increased protein up to 66 mg/dl without pleocytosis. In electrophysiological examinations, persistant multifocal conduction blocks in the motor nerves were predominantly noted in the distal part of the extremities. Serum titers of anti-Campylobacter jejuni antibody, anti-GM1 antibody and anti-GalNAc-GD1a antibody were elevated. Muscle weakness resolved completely within 7 weeks. The sural nerve biopsy did not reveal either axonal degeneration, nor demyelination. These clinical and laboratory findings suggested that this case was most likely an acute type of MMNCB after Campylobacter jejuni enteritis.

Absence of facilitation or depression of motor evoked potentials after contralateral homologous muscle activation

We have previously described post-exercise facilitation and post-exercise depression of motor evoked potentials (MEPs) to transcranial magnetic stimulation (TMS). To determine the presence of post-exercise facilitation after exercise of a contralateral muscle, MEPs were recorded from the resting right extensor carpi radialis (ECR) muscle while the left ECR muscle was activated, then immediately after brief left ECR activation, and, finally, immediately after brief right ECR activation. We repeated the experiment using the first dorsal interosseous (FDI) muscle. To determine the presence of post-exercise depression after exercise of a contralateral muscle, MEPs were recorded from the right ECR after prolonged exercise of the left ECR, followed by right ECR recording after its fatigue. The mean MEP amplitudes from the right ECR and the right FDI after brief activation were 187% and 266% of their pre-exercise values, respectively. There were no significant changes in MEPs recorded from the right ECR or FDI muscles during or immediately after brief activation of their left counterparts. The mean amplitude of MEPs recorded from the right ECR after it fatigued was approximately half the pre-exercise value, but there was no significant change in MEPs recorded from the right ECR after prolonged exercise of the left ECR. Therefore, neither post-exercise facilitation nor post-exercise depression occurred after contralateral homologous muscle exercise.

Effects of transcranial electrical and magnetic stimulation on reciprocal inhibition in the human arm

We studied the effects of transcranial electrical stimulation (TES) and transcranial magnetic stimulation (TMS), delivered at intensities below the threshold for evoking an electromyographic response, on the disynaptic and presynaptic phases of reciprocal inhibition in 8 healthy subjects. After TES, the H-reflex evoked in the flexor carpi radialis (FCR) muscle was strongly facilitated when the cortical stimulus was given 4.0-4.5 ms after the test stimulus (median nerve stimulus). TES reduced the disynaptic phase of reciprocal inhibition most strongly when the cortical stimulus followed the test stimulus by 3.0-3.5 ms. TES also reduced presynaptic inhibition, but with a time course that was identical to that of the facilitation of the uninhibited H-reflex. After subthreshold TMS, the facilitation of the H-reflex showed at least 2 peaks, one occurring when the cortical stimulus was given 2 ms after the test stimulus and the other when the cortical stimulus followed the test stimulus by 0.5 to -1.5 ms. The effects of TMS on the 2 phases of reciprocal inhibition were similar, and in both cases the disinhibitory effects had essentially the same time course as the facilitatory effect of TMS on the uninhibited H-reflex. The different effects of TES on the 2 phases of reciprocal inhibition provide evidence of the presynaptic nature of the second phase. The absence of a difference in the effect of TMS on the 2 phases could be due to the more temporally dispersed descending volley after TMS.

Decreased postexercise facilitation of motor evoked potentials in patients with chronic fatigue syndrome or depression

We studied the effects of exercise on motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) in 18 normal (control) subjects, 12 patients with chronic fatigue syndrome, and 10 depressed patients. Subjects performed repeated sets of isometric exercise of the extensor carpi radialis muscle until they were unable to maintain half maximal force. MEPs were recorded before and after each exercise set and for up to 30 minutes after the last set. The mean amplitude of MEPs recorded from the resting muscle immediately after each exercise set was 218% of the mean pre-exercise MEP amplitude in normal subjects, 126% in chronic fatigue patients, and 155% in depressed patients, indicating postexercise MEP facilitation in all three groups. The increases in the patient groups, however, were significantly lower than normal. The mean amplitudes of MEPs recorded within the first few minutes after the last exercise sets in all three groups were approximately half their mean pre-exercise MEP amplitudes. This postexercise MEP depression was similar in all groups. We conclude that postexercise cortical excitability is significantly reduced in patients with chronic fatigue syndrome and in depressed patients compared with that of normal subjects.

Abnormal cortical motor excitability in dystonia

To assess the excitability of the motor system, we studied 11 patients with task-specific dystonia and 11 age-matched normal subjects. The dominant side was affected in nine of the patients. We delivered transcranial magnetic stimuli at different stimulus intensities and with different levels of muscle facilitation to the side contralateral to the side of electromyographic recording, and recorded motor evoked potentials (MEPs) from the flexor carpi radialis muscles bilaterally. The threshold intensity for eliciting MEPs at rest did not differ between patients and normal subjects. We compared the affected side in patients with the dominant side in normal subjects. With facilitation, the percentage of the area of the MEP to the M wave (MEP area%) was similar in both groups at low stimulus intensities, but with increasing stimulus intensity the increase in the MEP area% was greater in patients than in normal subjects (ANOVA, p < 0.001). The increase in MEP area% was similar in both groups with increasing facilitation levels. The duration of the silent period was similar in patients and normal subjects. We conclude that cortical motor excitability is increased in dystonia.

Characterization of postexercise facilitation and depression of motor evoked potentials to transcranial magnetic stimulation

We studied the effects of exercise on motor evoked potentials (MEPs) to transcranial magnetic stimulation (TMS) and transcranial electrical stimulation (TES). Subjects performed 30-second periods of isometric exercise of the extensor carpi radialis until fatigue, which was defined as the inability to maintain half maximum force. The amplitude of MEPs to TMS recorded from the resting muscle after each exercise period was on average more than twice the pre-exercise value (postexercise MEP facilitation). After fatigue occurred, the MEP amplitudes were approximately 60% of the pre-exercise value (postexercise MEP depression). There was a gradual recovery of the depressed MEPs to pre-exercise values over several minutes of rest. Postexercise MEP facilitation was constant when exercise intensity ranged from 10 to 50% of maximum voluntary contraction and it decayed to baseline over several minutes after the end of exercise. There was no postexercise MEP facilitation to TES. We hypothesize that both postexercise MEP facilitation and MEP depression are due to intracortical mechanisms.

Responses to paired transcranial magnetic stimuli in resting, active, and recently activated muscles

Transcranial magnetic stimulation (TMS) causes the corticospinal system to become refractory to subsequent stimuli for up to 200 ms. We examined the phenomenon of paired pulse inhibition with TMS under conditions of rest, ongoing voluntary activation (isometric force generation), and at variable delays following activation (postactivation) of the wrist extensors of seven normal subjects. Paired stimuli were delivered to the motor cortex with a circular coil at 1.1 times motor evoked potential (MEP) threshold, with various interstimulus intervals. Voluntary activation caused a marked decrease in the variability of the ratio of the amplitude of the MEP evoked by the test pulse to that of the MEP evoked by the conditioning pulse. Marked inhibition of the MEP evoked by the test pulse was still present. Postactivation, however, caused a dramatic reversal of the inhibitory effect of the conditioning pulse in all subjects at interstimulus intervals ranging from 40 to 120 ms. This effect lasted for up to 10 s following the cessation of activation. MEPs to transcranial electrical stimulation were also inhibited by conditioning TMS, but postactivation did not reverse this inhibition, indicating that the reversal of paired pulse inhibition is intracortical. We conjecture that paired pulse inhibition reflects activity of inhibitory interneurons or inhibitory connections between cortical output cells that are inactivated in the postactivation state.

Cortical modulation of spinal excitability: an F-wave study

F-waves are known to be highly sensitive to changes in the excitatory state of the spinal cord. This paper describes the effects of subthreshold transcranial magnetic stimulation on the F-waves evoked in hand and foot muscles. In the abductor pollicis brevis muscle, the F-wave was significantly enhanced when the cortical stimulus was given with a delay corresponding approximately to the expected time of collision, i.e., the difference between the mean latency of the F-wave and the mean latency of the motor evoked potential. A second, usually larger facilitatory phase follows the first phase after 2-3 msec, and later peaks of enhancement often occurred. After the enhancement periods, a significant inhibition of the F-wave was usually observed. In the extensor digitorum brevis muscle, the first facilitatory phase was observed some milliseconds earlier than expected in 4 of 5 subjects, and the inhibitory phase was less pronounced. We argue that the sequential arrival of I-waves at the spinal segment could be responsible for the changes observed in the F-wave recorded from the small hand muscle. In the foot muscle, anatomical and technical factors could contribute to the generation of a D-wave. The strong inhibition observed in the F-wave recorded from the hand muscle is likely to be due to the arrival on alpha-motoneurons of inhibitory postsynaptic potentials (IPSPs) generated by the cortical stimulus. Our data show that the F-wave ia a probe for changes in the spinal cord excitatory state.

Pulsed magnetic stimulation and F waves in Parkinson's disease

Twenty-two patients with Parkinson's disease with predominantly unilateral signs in the upper extremities were studied by means of transcranial magnetic stimulation. The mean central motor conduction time (CMCT) on the clinically affected side determined by F wave technique was significantly shorter (p < .01) than that of the other side at rest. However, the mean CMCT during slight voluntary contraction was not significantly different in the two sides. Amplitudes of motor evoked potentials and F waves tended to be higher on the clinically affected side than on the other side. We conclude that reduced CMCT and high F wave amplitudes reflect hyperexcitability of the anterior horn cells in patients with Parkinson's disease.

Hereditary elliptocytosis associated with spectrin Le Puy in a Japanese family: ultrastructural aspect of the red cell skeleton

A dominantly-inherited hereditary elliptocytosis of intermediate severity was recorded in a Japanese family from Yamagata. The condition was associated with a spectrin truncated beta-chain (MW: 214 kD; 31% of total beta-spectrin), and a defect of mutant spectrin as regards tetramerization and phosphorylation. cDNA analysis revealed skipping of exon X, the third-to-last exon of the spectrin beta-gene. At the gene level, a one-base substitution (A-->G) changed position +4 of the 5' donor splice site consensus sequence of intron X. This mutation has been described before in a French kindred, defining spectrin Le Puy. Electron micrographs following quick-freeze deep-etching showed that the skeletal network was disorganized.

A clinicophysiologic study of central and peripheral motor conduction in hereditary demyelinating motor and sensory neuropathy

Central and peripheral motor nerve conduction were analyzed in 13 patients with hereditary demyelinating motor and sensory neuropathy using central magnetic stimulation and peripheral electrodiagnostic techniques. All patients showed a marked decrease in peripheral nerve conduction velocity. In 11 patients, the central motor conduction time was slightly prolonged but in 2 it was markedly prolonged suggesting dysfunction of the corticospinal tract. These two patients exhibited marked weakness and atrophy of distal muscles without clinical signs of upper motor neuron dysfunction, which was considered to be masked by the lower motor neuron disorder. This study suggests that in some patients with hereditary demyelinating polyneuropathy central as well as peripheral nerve fibers may be affected.

Central motor conductivity in aged people

The conductivity of motor neurons in 26 aged females (mean age 79 years) was analyzed by the conventional conduction method and by pulsed magnetic stimulation and compared with that in 14 younger controls. In aged people, slow motor conduction velocities were found in peripheral nerves. Central motor conduction time (CMCT) in relaxed muscle was shorter in the aged people, although CMCT was normal in mildly contracted muscle. These findings coincide with the results studied in Parkinson's disease, although these subjects were not diagnosed as having Parkinson's disease. Aged people generally have an anteflexed posture, slow movements, and poor postural reflexes, and have been reported to have a decrease in the dopamine level which is relatively earlier than that of other transmitters in the basal ganglia. This may account for the present finding that aged people have neurophysiological abnormalities in CNS which are similar to those in Parkinson's disease.

[Central motor conduction time (CMCT) in hereditary motor sensory neuropathy type I (HMSN type I)]

The motor system of 13 cases with hereditary motor sensory neuropathy (HMSN) type I were analysed by clinical neurophysiological method. The motor conduction velocity (MCV) and F wave latency in lower motor neurone were markedly delayed. The latency of the muscle evoked potential (MEP) by cortical magnetic stimulation were also markedly delayed. The central motor conduction times (CMCT) were calculated by two methods. CMCT-mag was calculated by subtraction of the MEP by cervical magnetic stimulation from the MEP by cortical magnetic stimulation. CMCT-f was calculated by subtraction of the [(F wave latency -1 + distal latency)/2] from the MEP by cortical magnetic stimulation. There were positive correlation between CMCT-f and CMCT-mag. CMCT of HMSN type I were divided to two groups. CMCT of the first group was markedly delayed. CMCT of the second group was mildly delayed or normal. The former group showed marked weakness in distal muscles clinically. The latter group showed mild or moderate weakness in distal muscles clinically. All these patients did not show any pyramidal tract signs, which could be covered by severe lower motor neurone involvements. The classification of HMSN type I by gene was well known, genetical analysis might be important to these groups in HMSN type I.

[Detection of HTLV-I/ATLV by using the culture of lymph node lymphocytes with adult T-cell leukemia/lymphoma]

We cultured the cervical lymph node lymphocytes of a patient suffering from cutaneous T-cell lymphoma. His anti-ATLV antibody was positive by indirect immunofluorescent method (IF). ATLV was detected on these cultured cells by IF. Type C particles were observed in the cultured cells by electron microscopy. These particles were measured to be 60 to 120 nm in diameter with electron dense core, and were considered as ATLV. This case showed a possibility of detecting ATLV by culture of lymph node lymphocytes from such a patient.