Comparison between early and late carotid endarterectomy for symptomatic carotid stenosis in relation to oxidized low-density lipoprotein and plaque vulnerability

ObjectiveAlthough carotid endarterectomy (CEA), the gold standard in stroke prevention, has been performed in the late stage after the insult, its optimal timing remains unclear. Using biomarkers in plaque and plasma, we evaluated oxidative stress and plaque vulnerability between early and late CEA in symptomatic patients.MethodsWe compared symptomatic stroke patients who underwent early CEA within 4 weeks of the last insult (group A; n = 15) with those who received CEA in the late stage beyond 4 weeks from the last symptom (group B; n = 57). They were divided into vulnerable (group Av, n = 13; group Bv, n = 33) and stable (group As, n = 2; group Bs, n = 24) subgroups according to the pathologic findings on their plaques. We studied the relationships among their primary symptoms, clinical findings, oxidized low-density lipoprotein levels, and gelatinase A (matrix metalloproteinase [MMP]-9) activity in their plaques and plasma.ResultsGroup A had a variety of symptoms; there was no difference in the outcome of CEA between groups A and B. The plaque and plasma oxidized low-density lipoprotein levels were higher in group A than in group B (P < .05). The incidence of pathologically vulnerable plaque was higher in group A than in group B. Plaque oxidized low-density lipoprotein levels and MMP-9 activity were similar in group Av and group Bv and were higher in those groups than in group As and Bs.ConclusionsWe first demonstrated that vulnerable plaques in patients subjected to early CEA manifested a remarkable increase in oxidized low-density lipoprotein and MMP-9 activation. Our findings suggest that early CEA may be beneficial in the aspect of oxidative stress

Neural mechanisms of motion sickness

Three kinds of neurotransmitters : histamine, acetylcholine and noradrenaline, play important roles in the neural processes of motion sickness, because antihistamines, scopolamine and amphetamine are effective in preventing motion sickness. Histamine H1-receptors are involved in the development of the symptoms and signs of motion sickness, including emesis. On provocative motion stimuli, a neural mismatch signal activates the histaminergic neuron system in the hypothalamus, and the histaminergic descending impulse stimulates H1-receptors in the emetic center of the brainstem. The histaminergic input to the emetic center through H1-receptors is independent of dopamine D2-receptors in the chemoreceptor trigger zone in the area postrema and serotonin 5HT3-receptors in the visceral afferent, which are also involved in the emetic reflex. Antihistamines block emetic H1-receptors to prevent motion sickness. Scopolamine prevents motion sickness by modifying the neural store to reduce the neural mismatch signal and by facilitating the adaptation/habituation processes. The noradrenergic neuron system in the locus coeruleus is suppressed by the neural mismatch signal. Amphetamine antagonizes mismatch-induced suppression of noradrenergic neural transmission, resulting in preventing motion sickness

Risk factors of first bite syndrome

Objective : First bite syndrome is a complication of surgical resection of parapharyngeal space tumors and the development of cramping pain in the parotid region with the first bite of a meal. The present study aimed to identify the potential risk factors for the development of first bite syndrome. Methods : We retrospectively reviewed 30 consecutive patients with parapharyngeal space tumors who had been surgically treated between August 2003 and December 2015 at our department. Results : The tumor site (prestyloid or retrostyloid) and surgical approach (transcervical-parotid, transparotid, or transcervical) were not correlated with the development of first bite syndrome. Ligation and mobilization of the external carotid artery was significantly correlated with the development of first bite syndrome. Moreover, patients with complete resection of the parotid gland did not experience first bite syndrome. Discussion : The present findings suggest that concomitant surgical settings of 1) sympathetic denervation of the parotid gland with ligation of the external carotid artery or injury of the sympathetic nerve plexus around the external carotid artery during its mobilization, and 2) residual parotid gland tissue are risk factors for the development of first bite syndrome after surgical resection of parapharyngeal space tumors

The effect of visual-vestibulosomatosensory conflict induced by virtual reality on postural stability in humans

In this study, we examined the effects of sensory inputs of visual-vestibulosomatosensory conflict induced by virtual reality (VR) on subjective dizziness, posture stability and visual dependency on postural control in humans. Eleven healthy young volunteers were immersed in two different VR conditions. In the control condition, subjects walked voluntarily with the background images of interactive computer graphics proportionally synchronized to their walking pace. In the visual-vestibulosomatosensory conflict condition, subjects kept still, but the background images that subjects experienced in the control condition were presented. The scores of both Graybiel’s and Hamilton’s criteria, postural instability and Romberg ratio were measured before and after the two conditions. After immersion in the conflict condition, both subjective dizziness and objective postural instability were significantly increased, and Romberg ratio, an index of the visual dependency on postural control, was slightly decreased. These findings suggest that sensory inputs of visual-vestibulosomatosensory conflict induced by VR induced motion sickness, resulting in subjective dizziness and postural instability. They also suggest that adaptation to the conflict condition decreases the contribution of visual inputs to postural control with re-weighing of vestibulosomatosensory inputs. VR may be used as a rehabilitation tool for dizzy patients by its ability to induce sensory re-weighing of postural control

免疫組織化学法を用いた一側内耳破壊ラットの前庭代償の新しい評価法の開発

Background: Unilateral labyrinthectomy (UL) causes the disappearance of ipsilateral medial vestibular nuclear (ipsi-MVe) activity and induces spontaneous nystagmus (SN), which disappears during the initial process of vestibular compensation (VC). Ipsi-MVe-activity restores in the late process of VC. Objective: We evaluated the late process of VC after UL in rats and examined the effects of thioperamide (H3 antagonist) on VC. Materials and methods: MK801 (NMDA antagonist)-induced Fos-like immunoreactive (-LIR) neurons in contra-MVe, which had been suppressed by NMDA-mediated cerebellar inhibition in UL-rats was used as an index. Results: The number of MK801-induced Fos-LIR neurons in contra-MVe gradually decreased to the same level as that of sham-operated rats 14 days after UL. Thioperamide moved the disappearance of the MK801-induced Fos-LIR neurons 2 days earlier. The number of MK801-induced Fos-LIR neurons in thioperamide-treated rats was significantly decreased, compared with that of vehicle-rats on days 7 and 12 after UL. But, thioperamide did not influence the decline of SN frequency in UL-rats. Conclusion: There findings suggested that the number of MK801-induced Fos-LIR neurons in contra-MVe was decreased in concordance with the restoration of ipsi-MVe-activity during the late process of VC after UL and that thioperamide accelerated the late, but not the initial process of VC

Comparison of the efficacy of the Epley maneuver and repeated Dix–Hallpike tests for eliminating positional nystagmus: A multicenter randomized study

Background and objectivesPatients with benign paroxysmal positional vertigo of the posterior canal (pc-BPPV) exhibit BPPV fatigue, where the positional nystagmus diminishes with the repeated performance of the Dix–Hallpike test (DHt). BPPV fatigue is thought to be caused by the disintegration of lumps of otoconial debris into smaller parts and can eliminate positional nystagmus within a few minutes [similar to the immediate effect of the Epley maneuver (EM)]. In this study, we aimed to show the non-inferiority of the repeated DHt to the EM for eliminating positional nystagmus after 1 week.MethodsThis multicenter, randomized controlled clinical trial was designed based on the CONSORT 2010 guidelines. Patients who had pc-BPPV were recruited and randomly allocated to Group A or Group B. Patients in Group A were treated using the EM, and patients in Group B were treated using repeated DHt. For both groups, head movements were repeated until the positional nystagmus had been eliminated (a maximum of three repetitions). After 1 week, the patients were examined to determine whether the positional nystagmus was still present. The groups were compared in terms of the percentage of patients whose positional nystagmus had been eliminated, with the non-inferiority margin set at 15%.ResultsData for a total of 180 patients were analyzed (90 patients per group). Positional nystagmus had been eliminated in 50.0% of the patients in Group A compared with 47.8% in Group B. The upper limit of the 95% confidence interval for the difference was 14.5%, which was lower than the non-inferiority margin.DiscussionThis study showed the non-inferiority of repeated DHt to the EM for eliminating positional nystagmus after 1 week in patients with pc-BPPV and that even the disintegration of otoconial debris alone has a therapeutic effect for pc-BPPV. Disintegrated otoconial debris disappears from the posterior canal because it can be dissolved in the endolymph or returned to the vestibule via activities of daily living.Classification of evidenceThis study provides Class II evidence of the non-inferiority of repeated DHt to the EM for eliminating positional nystagmus after 1 week.Registration numberUMIN000016421

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements