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Saccadic oscillations (SOs) mostly occur spontaneously, but can be occasionally triggered by various stimuli. To determine clinical characteristics and underlying mechanisms of triggered SOs, we analyzed the clinical features and quantitative eye-movement recordings of six new patients and 10 patients in the literature who exhibited with triggered SOs. Eleven of the 16 patients (69%) had a lesion involving cerebellum and/or brainstem such as cerebellar degeneration, cerebellitis, or cerebellar infarction. The other causes were vestibular migraine (n = 2), multiple sclerosis (n = 1), Krabbe disease (n = 1), and idiopathic (n = 1). Vestibular stimulation was the most common trigger (n = 11, 69%), followed by removal of visual fixation (n = 4, 25%), hyperventilation (n = 1), light (n = 1), and blink (n = 1). The types of triggered SOs were varied which included ocular flutter (n = 13), opsoclonus (n = 3), vertical SOs (n = 2), and macrosaccadic oscillations (n = 1). Three patients exhibited downbeat nystagmus either before (n = 1) or after (n = 2) the onset of SOs. The frequency of triggered SOs ranged from 4 to 15 Hz, and oscillations with smaller amplitudes had higher frequencies and smaller peak velocities. SOs can be triggered by the modulation of unstable saccadic neural networks through vestibular and visual inputs in lesions of the brainstem and cerebellum.
Subject(s)
Ocular Motility Disorders , Saccades , Humans , Saccades/physiology , Female , Male , Middle Aged , Adult , Ocular Motility Disorders/etiology , Ocular Motility Disorders/physiopathology , Aged , Young AdultABSTRACT
In evidence-based medicine, systematic review continues to carry the highest weight in terms of quality and reliability, synthesizing robust information from previously published cohort studies to provide a comprehensive overview of a topic. Meta-analysis provides further depth by allowing for comparative analysis between the studied intervention and the control group, providing the most up-to-date evidence on their characteristics and efficacy. We discuss the principles and methodology of meta-analysis, and its applicability to the field of surgical research. The clinical question is defined using PICO framework (Problem, Intervention, Comparison, Outcome). Then a systematic article search is performed across multiple medical databases using relevant search terms, which are then filtered out based on appropriate screening tools. Pertinent data from the selected articles are collected and undergo critical appraisal by at least two independent reviewers. Additional statistical tests may be performed to identify the presence of any significant bias. The data are then synthesized to perform comparative analysis between the intervention and comparison groups. In this article, we discuss specifically the usage of R software (R Foundation for Statistical Computing, Vienna, Austria) for data analysis and visualization. Meta-analysis results of the pooled data are presented using forest plots. Concerns for potential bias may be addressed through the creation of funnel plots. Meta-analysis is a powerful tool to provide highly reliable medical evidence. It may be readily performed by independent researchers with minimal need for funding or institutional approval. The ability to conduct such studies is an asset to budding medical scholars.
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BACKGROUND: Despite recent advancements, the advantage of robotic surgery over other traditional modalities still harbors academic inquiries. We seek to take a recently published high-profile narrative systematic review regarding robotic surgery and add meta-analytic tools to identify further benefits of robotic surgery. METHODS: Data from the published systematic review were extracted and meta-analysis were performed. A fixed-effect model was used when heterogeneity was not significant (Chi2 p ≥ 0.05, I2 ≤ 50%) and a random-effects model was used when heterogeneity was significant (Chi2 p < 0.05, I2 > 50%). Forest plots were generated using RevMan 5.3 software. RESULTS: Robotic surgery had comparable overall complications compared to laparoscopic surgery (p = 0.85), which was significantly lower compared to open surgery (odds ratio 0.68, p = 0.005). Compared to laparoscopic surgery, robotic surgery had fewer open conversions (risk difference - 0.0144, p = 0.03), shorter length of stay (mean difference - 0.23 days, p = 0.01), but longer operative time (mean difference 27.98 min, p < 0.00001). Compared to open surgery, robotic surgery had less estimated blood loss (mean difference - 286.8 mL, p = 0.0003) and shorter length of stay (mean difference - 1.69 days, p = 0.001) with longer operative time (mean difference 44.05 min, p = 0.03). For experienced robotic surgeons, there were less overall intraoperative complications (risk difference - 0.02, p = 0.02) and open conversions (risk difference - 0.03, p = 0.04), with equivalent operative duration (mean difference 23.32 min, p = 0.1) compared to more traditional modalities. CONCLUSION: Our study suggests that compared to laparoscopy, robotic surgery may improve hospital length of stay and open conversion rates, with added benefits in experienced robotic surgeons showing lower overall intraoperative complications and comparable operative times.
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Robotic Surgical Procedures , Humans , Abdomen/surgery , Conversion to Open Surgery/statistics & numerical data , Laparoscopy/methods , Length of Stay/statistics & numerical data , Operative Time , Pelvis/surgery , Postoperative Complications/epidemiology , Postoperative Complications/etiology , Randomized Controlled Trials as Topic , Robotic Surgical Procedures/methods , Robotic Surgical Procedures/adverse effectsABSTRACT
BACKGROUND AND PURPOSE: Diagnosis of lymphoma involving the central nervous system (CNS) is challenging. This study aimed to explore the abnormal vestibular and ocular motor findings in CNS lymphoma. METHODS: A retrospective search of the medical records identified 30 patients with CNS lymphoma presenting ocular motor and vestibular abnormalities from four neurology clinics of university hospitals in South Korea (22 men, age range 14-81 years, mean 60.6 ± 15.2). The demographic and clinical features and the results of laboratory, radiological and pathological evaluation were analyzed. RESULTS: Patients presented with diplopia (13/30, 43%), vestibular symptoms (15/30, 50%) or both (2/30, 7%). In 15 patients with diplopia, abnormal ocular motor findings included ocular motor nerve palsy (n = 10, 67%), internuclear ophthalmoplegia (n = 2, 13%), external ophthalmoplegia (n = 2, 13%) and exophoria (n = 1, 7%). The vestibular abnormalities were isolated in 14 (82%) of 17 patients with vestibular symptoms and included combined unilateral peripheral and central vestibulopathy in three from lesions involving the vestibular nuclei. CNS lymphoma involved the brainstem (53%), cerebellum (33%), leptomeninges (30%), deep gray nuclei (23%) or cranial nerves (17%). Two patients showed the "double-panda" sign by involving the midbrain. CONCLUSIONS: This study expands the clinical and radiological spectra of CNS lymphoma. Neuro-ophthalmological and neuro-otological evaluation may guide the early diagnosis of CNS lymphoma.
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Diplopia , Ocular Motility Disorders , Male , Humans , Adolescent , Young Adult , Adult , Middle Aged , Aged , Aged, 80 and over , Retrospective Studies , Ocular Motility Disorders/diagnosis , Eye Movements , Cerebellum , ParalysisABSTRACT
BACKGROUND AND PURPOSE: The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) have been identified as useful biomarkers for assessing the inflammatory response and for predicting the prognosis of various diseases. This study aimed to determine the clinical significance and effects on prognostic prediction of NLR and PLR in acute unilateral vestibulopathy (AUV). METHODS: We retrospectively recruited 128 patients who were diagnosed with AUV from July 2016 to April 2021, and compared NLR and PLR values between these patients with AUV and age- and sex-matched healthy subjects. We also analyzed the correlations of various clinical parameters with NLR and PLR. RESULTS: NLR and PLR in the AUV group were 3.41±2.80 (mean±standard deviation) and 128.86±67.06, respectively, with only NLR being significantly higher than that in the control group (1.55±0.60, p<0.001). The gain asymmetry of the horizontal vestibulo-ocular reflex (VOR) was slightly larger in patients with high NLR (n=52) than in those with normal NLR (n=76) (41.9%±20.2% vs. 33.6%±17.4%, p=0.048). However, the hospitalization period, preceding infection, canal paresis, and absolute horizontal VOR gain did not differ between patients with high and normal NLR and PLR values. The correlation analyses also revealed that none of the clinical parameters were significantly correlated with NLR or PLR. At 3-month follow-up examinations, NLR and PLR did not differ significantly between patients with and without function recovery of the horizontal VOR. CONCLUSIONS: This study found a high NLR in AUV, suggesting an acute inflammatory status in the vestibular organ. However, the usefulness of NLR and PLR as prognostic markers remains unclear.
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OBJECTIVE: This study aimed to correlate the symptoms and signs with the findings of laboratory vestibular function tests in patients with spinocerebellar ataxia (SCA). METHOD: We retrospectively recruited 26 patients with SCA (9 men, median age: 52, age range: 21-67). Assessments included Dizziness Handicap Inventory, EuroQoL Five-Dimension, symptom questionnaires manifesting during walking in daily life, the Scale for the Assessment and Rating of Ataxia (SARA), and vestibular function tests including 3D video-oculography, video head impulse test, subjective visual vertical, and cervical and ocular vestibular evoked myogenic potentials (VEMP). RESULTS: Cross-analyses revealed that the patients with VEMP abnormalities showed higher SARA (p = 0.014) and prevalence of unpredictable falls (p = 0.046). The patients with SCA1 more frequently had unpredictable falls (75%, p = 0.038) and VEMP abnormalities (88%, p = 0.001) compared to SCA2 (29% falls, 17% VEMP abnormalities) and SCA6 (no falls or VEMP abnormalities). CONCLUSION: Abnormal VEMPs are strongly associated with unpredicted falls in patients with SCA, particularly in those with SCA1. Impaired processing of otolithic information may contribute to falls in SCAs, and VEMP may help identifying the patients with a risk for unpredicted falls and preventing fall-related injuries in SCA. Limited number of patients with lower SARA scores warrant further confirmatory studies.
Subject(s)
Accidental Falls , Spinocerebellar Ataxias , Vestibular Evoked Myogenic Potentials , Vestibular Function Tests , Humans , Male , Female , Vestibular Evoked Myogenic Potentials/physiology , Adult , Middle Aged , Spinocerebellar Ataxias/physiopathology , Spinocerebellar Ataxias/complications , Aged , Young Adult , Retrospective Studies , Risk FactorsABSTRACT
Melanoma, a highly malignant and aggressive form of skin cancer, poses a significant global health threat, with limited treatment options and potential side effects. In this study, we developed a temperature-responsive hydrogel for skin regeneration with a controllable drug release. The hydrogel was fabricated using an interpenetrating polymer network (IPN) of N-isopropylacrylamide (NIPAAm) and poly(vinyl alcohol) (PVA). PVA was chosen for its adhesive properties, biocompatibility, and ability to address hydrophobicity issues associated with NIPAAm. The hydrogel was loaded with doxorubicin (DOX), an anticancer drug, for the treatment of melanoma. The NIPAAm-PVA (N-P) hydrogel demonstrated temperature-responsive behavior with a lower critical solution temperature (LCST) around 34 °C. The addition of PVA led to increased porosity and faster drug release. In vitro biocompatibility tests showed nontoxicity and supported cell proliferation. The N-P hydrogel exhibited effective anticancer effects on melanoma cells due to its rapid drug release behavior. This N-P hydrogel system shows great promise for controlled drug delivery and potential applications in skin regeneration and cancer treatment. Further research, including in vivo studies, will be essential to advance this hydrogel system toward clinical translation and impactful advancements in regenerative medicine and cancer therapeutics.
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Objectives: This study aimed to determine the pathophysiology of recurrent benign paroxysmal positional vertigo (BPPV) in young patients using gene expression profiling combined with bioinformatics analysis. Methods: Total RNA was extracted from the whole blood of four young patients with recurrent BPPV and four controls. The differentially expressed genes (DEGs) between the groups were screened using a microarray analysis based on the cutoff criteria of |log2 fold change| > 1 and an adjusted p-value of < 0.05. Functional enrichment analysis of DEGs was performed using Gene Ontology analysis, and the protein-protein interaction (PPI) network was constructed using the Search Tool for the Retrieval of the Interacting Genes database. Results: A total of 39 DEGs were detected between the BPPV and control samples, comprising 33 upregulated DEGs and six downregulated DEGs in the BPPV group. Functional enrichment analysis indicated that the upregulated DEGs were significantly enriched in terms related to metabolic processes and the immune system. Two main pathways were extracted from the PPI network: one was associated with oxidative phosphorylation and stress and the other with the adaptive immune system and extracellular matrix degradation. Conclusion: The findings of our bioinformatics analysis indicated that oxidative stress or extracellular matrix degradation due to immune-mediated inflammatory responses may contribute to the development of recurrent BPPV in young patients.
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INTRODUCTION: Contributing factors to postlaparoscopy hernia are unknown. We hypothesized that postlaparoscopy incisional hernias are increased when the index surgery was performed in teaching hospitals. Laparoscopic cholecystectomy was chosen as the archetype for open umbilical access. MATERIALS AND METHODS: Maryland and Florida SID/SASD databases (2016-2019) wereused to track 1-year hernia incidence in both inpatient and outpatient settings, which was then linked to Hospital Compare, Distressed Communities Index (DCI), and ACGME. Postoperative umbilical/incisional hernia following laparoscopic cholecystectomy was identified using CPT and ICD-10. Propensity matching and eight machine learning modes were utilized including logistic regression, neural network, gradient boosting machine, random forest, gradient boosted trees, classification and regression trees, k nearest neighbors and support vector machines. RESULTS: Postoperative hernia incidence was 0.2% (total = 286; 261 incisional and 25 umbilical) in 117,570 laparoscopic cholecystectomy cases. Days to presentation (mean ± SD) were incisional 141 ± 92 and umbilical 66 ± 74. Logistic regression performed best (AUC 0.75 (95% ci 0.67-0.82) and accuracy 0.68 (95% ci 0.60-0.75) using 10-fold cross validation) in propensity matched groups (1:1; n = 279). Postoperative malnutrition (OR 3.5), hospital DCI of comfortable, mid-tier, at risk or distressed (OR 2.2 to 3.5), LOS >1 d (OR 2.2), postop asthma (OR 2.1), hospital mortality below national average (OR 2.0) and emergency admission (OR 1.7) were associated with increased hernias. A decreased incidence was associated with patient location of small metropolitan areas with <1 million residents (OR 0.5) and Charlson Comorbidity Index-Severe (OR 0.5). Teaching hospitals were not associated with postoperative hernia after laparoscopic cholecystectomy. CONCLUSIONS: Different patient factors as well as underlying hospital factors are associated with postlaparoscopy hernias. Performance of laparoscopic cholecystectomy at teaching hospitals is not associated with increased postoperative hernias.
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Cholecystectomy, Laparoscopic , Hernia, Ventral , Incisional Hernia , Laparoscopy , Humans , Incisional Hernia/epidemiology , Incisional Hernia/etiology , Incisional Hernia/surgery , Cholecystectomy, Laparoscopic/adverse effects , Hospitalization , Incidence , Databases, Factual , Laparoscopy/adverse effects , Hernia, Ventral/surgery , Postoperative Complications/diagnosis , Postoperative Complications/epidemiology , Postoperative Complications/etiologyABSTRACT
Background: Many kinds of vaccines have been developed worldwide to bring the coronavirus disease 2019 (COVID-19) to an end. We report a case of recurrent orbital apex syndrome following the first and third doses of SARS-CoV-2 vaccination. Case presentation: A 71-year-old woman presented with acute painless diplopia and visual disturbance for two days. She had received the first dose of the COVID-19 vaccine two weeks before. She showed decreased visual acuity and ophthalmoplegia in the right eye. An orbital magnetic resonance image (MRI) revealed a hyperintense lesion with enhanced bulging in the right cavernous sinus. Following the steroid pulse therapy, she fully recovered. However, six months after the first attack, painful ophthalmoplegia with decreased visual acuity recurred in her left eye after the booster vaccination for COVID-19. MRI also showed a well-enhanced hyperintense lesion in the left orbital apex. Fortunately, her visual acuity and ocular motility returned to normal after the steroid therapy. Conclusions: Immunologic reactions from COVID-19 vaccines may cause multiple cranial neuropathies. Diverse individual immunologic states should be considered before any kind of vaccine.
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PURPOSE: To describe the clinical characteristics and posterior vitreous findings of spontaneous reattachment of rhegmatogenous retinal detachment (SRRRD). METHODS: Eighty-six eyes from 80 patients who were diagnosed with SRRRD (SRRRD group) and 92 eyes from 92 patients who had undergone successful scleral buckling for rhegmatogenous retinal detachment ( group for comparison) were included. Ultrawide field fundus imaging and spectral domain optical coherence tomography were performed to evaluate fundus characteristics and vitreoretinal interface. RESULTS: A significant difference was found in the proportion of complete posterior vitreous attachment between the SRRRD and rhegmatogenous retinal detachment groups (44.2% vs. 19.6%, P < 0.001). The incidence of atypical epiretinal tissue (AET) in the SRRRD group was 14% (12 of 86 eyes), whereas none of the eyes in the rhegmatogenous retinal detachment group exhibited AET. In SRRRD eyes with AET, the visual acuity was lower (logarithm of the minimum angle of resolution, 0.51 ± 0.57 vs. 0.14 ± 0.15, P < 0.001), the mean age was higher (years, 61.7 vs. 39.4, P < 0.001), and the SRRRD lesion extent was wider (clock hours, 5.67 vs. 3.70, P = 0.004) than in SRRRD eyes without AET. CONCLUSION: Compared with the rhegmatogenous retinal detachment group, the SRRRD group had a higher incidence of posterior vitreous attachment. Furthermore, AET was a significant comorbidity in the eyes with SRRRD, particularly in the elderly and the area of presumed reattachment over two quadrants and was related to worse functional outcomes.
Subject(s)
Retinal Detachment , Humans , Aged , Retinal Detachment/diagnosis , Retinal Detachment/surgery , Retinal Detachment/etiology , Scleral Buckling/adverse effects , Visual Acuity , Fundus Oculi , Vitrectomy/adverse effects , Retrospective StudiesABSTRACT
The incidence and characteristics of acute vestibular symptoms, responsible structures, and lateralization of the causative lesions in supratentorial stroke remain unknown. This study aimed to determine the incidence, clinical features, and anatomical correlation of acute vestibular symptoms in supratentorial stroke. We performed a prospective, multicenter, observational study that had recruited patients with supratentorial stroke from the neurology clinics of referral-based four university hospitals in Korea. All patients received a constructed neuro-otological evaluations, and neuroimaging. We analyzed the incidence of acute vestibular symptoms, abnormal ocular motor and vestibular function tests, and stroke lesions. Of 1301 patients with supratentorial stroke, 48 (3.7%) presented with acute vestibular symptoms, and 13 of them (1%) had the vestibular symptoms in isolation. In patients with acute vestibular symptoms, abnormal findings included spontaneous nystagmus (5%), impaired horizontal smooth pursuit (41%), and abnormal tilt of the subjective visual vertical (SVV) (20%). Video head impulse and caloric tests were normal in all the patients. There was no clear correlation between acute vestibular symptoms and involvement of specific vestibular cortex. In patients with unilateral stroke, there was also no lateralization of the causative lesions of acute vestibular symptoms (left vs. right; 52 vs. 48%), even in patients with vertigo (left vs. right; 58 vs. 42%). This study demonstrates that the incidence of acute vestibular symptoms in supratentorial stroke is 3.7%, with being isolated in 1%. The widespread lesions responsible for acute vestibular symptoms implicate diffuse multisensory cortical-subcortical networks in the cerebral hemispheres without a lateralization.
Subject(s)
Nystagmus, Pathologic , Stroke , Humans , Incidence , Prospective Studies , Vertigo/diagnosis , Stroke/complications , Stroke/diagnostic imaging , Stroke/epidemiology , Nystagmus, Pathologic/diagnostic imaging , Nystagmus, Pathologic/epidemiology , Nystagmus, Pathologic/etiologyABSTRACT
BACKGROUND: Improvement in continuous-flow left ventricular assist device (CF-LVAD) technology has translated to better outcomes for patients on CF-LVAD support as a bridge-to-transplant. However, data are lacking regarding the subset of CF-LVAD patients with renal failure awaiting simultaneous heart-kidney transplant (HKTx). We sought to better understand the characteristics and outcomes of patients in this group. METHODS: The United Network for Organ Sharing (UNOS) database was used to identify adult patients listed for heart transplant (HTx) or HKTx from January 1, 2009 to March 31, 2017. Patients were followed from time on waitlist to either removal from waitlist or transplantation. Demographic and clinical data for HTx and HKTx patients were assessed. Kaplan-Meier analysis assessed waitlist and post-transplant survival. For waitlisted patients, both death and removal from the waitlist due to deteriorating medical condition were considered events. RESULTS: Overall, 26 638 patients registered for transplant were analyzed. 25 111 (94%) were listed for HTx, and 1527 (6%) for HKTx. 7683 (29%) patients listed for HTx had CF-LVAD support. For those listed for HKTx, 441 (28%) underwent dialysis alone, 256 (17%) had CF-LVAD support alone, and 85 (6%) were treated with both CF-LVAD and dialysis. 15 567 (58%) underwent HTx, and 621 (2%) underwent HKTx. In these groups, post-transplant survival was similar (p = 0.06). Patients listed for HKTx treated with both dialysis and CF-LVAD had significantly worse waitlist survival compared to HKTx recipients (p < 0.001). CONCLUSION: Post-transplant survival is comparable between HTx and HKTx, and early survival is similar between HTx patients and those listed for HTx with CF-LVAD support. However, outcomes on the waitlist for HKTx in CF-LVAD patients on dialysis is significantly worse compared to HKTx recipients. This highlights the need to better account for this patient population when allocating organs.
Subject(s)
Heart Failure , Heart Transplantation , Heart-Assist Devices , Kidney Transplantation , Adult , Humans , Kidney Transplantation/adverse effects , Heart Failure/surgery , Heart-Assist Devices/adverse effects , Treatment Outcome , Heart Transplantation/adverse effects , Retrospective StudiesABSTRACT
Objectives: This study aimed to describe the clinical and radiological characteristics of a cerebello-brainstem dominant form of X-linked adrenoleukodystrophy (X-ALD). Methods: Three affected members from a family with cerebellar ataxia received full neurological, laboratory and radiological examinations. Genetic diagnoses were confirmed using whole-exome sequencing and protein structural modeling. Results: All affected members presented with slurred speech, ataxia, and spasticity, but showed obvious differences in phenotypic severity and radiological findings. The levels of very long-chain fatty acids (VLCFA) were elevated in each member, while only one had adrenal dysfunction. Genetic analysis identified a hemizygous missense mutation (c.887A>G, p.Tyr296Cys) of the ATP-binding cassette subfamily D member 1 gene (ABCD1) in all affected members, which is likely to destabilize the overall structure of the ABCD1 protein. Conclusions: We report a cerebello-dominant form of X-ALD caused by a missense variant in ABCD1. This report highlights intrafamilial phenotypic variability in X-ALD.
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Objectives: This study aimed to determine the underlying pathogenesis of Meniere's disease (MD) using transcriptome analysis. Methods: Total RNA was extracted from the peripheral blood mononuclear cells of 39 patients with MD and 39 controls. Through microarray analysis for nine patients and controls, the differentially expressed genes (DEGs) of those two groups were screened based on cut-off criteria (|fold changes| > 2.0 and adjusted p-value < 0.05). The functional enrichment analysis of DEGs was performed using Gene Ontology (GO). Results: There were 996 DEGs identified in the MD group: 415 were upregulated and 581 were downregulated. A functional enrichment analysis indicated that the downregulated DEGs were significantly enriched in terms related to immune system processes. Among them, 17 genes were enriched in terms for the major histocompatibility complex (MHC) protein complex, and the relative messenger RNA (mRNA) levels of three markedly downregulated DEGs [fold changes < -5: human leukocyte antigen (HLA)-DMA, HLA-DRB1, and HLA-DPB1] were significantly decreased in another 30 patients with MD compared with normal controls by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). However, there were no correlations between the expression levels of these three genes and clinical data, such as age, onset age, time course, or hearing threshold. Conclusions: Our transcriptome analysis showed that the downregulated DEGs in MD were mainly associated with the immune system pathways including the MHC protein complex in MD. Remarkably, a breakdown in immunological tolerance mediated by MHC class II may contribute to the MD development, which has implications for targeted treatment.
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Vertical pendular nystagmus (PN) rarely occurs with acute pontine lesions. To hypothesize a pathophysiology for acute vertical PN, we analyzed the clinical characteristics and quantitative eye-movement recordings of one new case with acute vertical PN and an additional 11 patients from the literature. Most patients had extensive pontine lesions causing either the locked-in syndrome or unresponsiveness, but two conscious patients had focal lesions restricted to the paramedian caudal pontine tegmentum. All patients presented a complete or partial horizontal gaze palsy, and about half showed ocular bobbing before or during the appearance of vertical PN. The vertical oscillations were conjugate at a frequency of 1-5 Hz, and the amplitudes were variable, ranging from 0.2° to 40°. The peak velocities were asymmetric in some patients, faster with downward movements. About half of the patients developed palatal tremor several weeks or months after presenting with acute vertical PN. Based on the location of the lesions and results of eye-movement recordings, we suggest two possible mechanisms for acute vertical PN; oscillations originating in the inferior olives due to disruption of the central tegmental tract or low-velocity saccadic oscillations caused by omnipause neuron damage.
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Nystagmus, Pathologic , Ocular Motility Disorders , Humans , Eye Movements , Pons/diagnostic imaging , Pons/pathology , Ocular Motility Disorders/complications , MovementABSTRACT
The operating parameters necessary to improve the desorption rate of a membrane capacitive deionization (MCDI) system while controlling the Faradaic reactions were studied. The total charge (QT) accumulated in the carbon electrode was set as the main operating parameter determining the desorption rate of the MCDI system. After adsorption was performed until the preset QT value was reached using the MCDI unit cell, desorption was performed at a cell potential of -0.2 V. As a result of this MCDI operation, the average desorption rate increased in proportion to the QT value. Additionally, the ratio of desorption charge according to the desorption time was consistent regardless of QT. Through this, it could be seen that the desorption process of the MCDI system is similar to the discharge characteristic of a series circuit comprising a resistor (R) and a capacitor (C). If the desorption time is too short during the MCDI operation, some charges will remain in the carbon electrode. When the adsorption charge (Qad) is supplied again, QT increases. When QT exceeds the maximum allowable charge (MAC), which is the total charge at the onset of Faradaic reactions, electrode reactions can occur. Through RC circuit analysis, a model equation for calculating the minimum desorption time required to operate a MCDI system without the occurrence of Faradaic reactions was derived. As a result of MCDI operation while changing the desorption time, the desalination performance almost matched the result predicted through the model equation. Additionally, it was found that the smaller Qad is, the shorter the desorption time, resulting in a higher desalination rate of the MCDI system.
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Water Purification , Adsorption , Carbon , Electrodes , Sodium Chloride , Water Purification/methodsABSTRACT
This study aimed to determine the incidence, pattern, and etiology of dissociated vestibulo-ocular reflex (VOR) function according to the stimulus frequency in dizzy patients. We retrospectively evaluated the results of bithermal caloric tests and video-head impulse tests (vHITs) in 1022 patients with dizziness or vertigo between July 2016 and April 2021. Patients were classified into concordant group (normal or abnormal results on both tests) and discordant group (dissociated results between two tests). Of 1022 patients, discordant group had 159 (16%), comprising abnormal horizontal vHITs with normal caloric responses (n = 36, 23%) and abnormal caloric tests with normal horizontal vHITs (n = 123, 77%). The former group showed similar frequency of peripheral (44%) and central (42%) causes, and more common involvement of bilateral horizontal semicircular canals in central than peripheral causes (86.7 vs 37.5%, p = 0.005). The most common peripheral causes were Meniere's disease and chronic vestibular neuritis, while central causes were variable, but mainly affecting the cerebellum. In the latter group, peripheral causes were common (67%), with the main etiologies being Meniere's disease and vestibular neuritis, whereas central causes were found in only 5%. The degree of canal paresis did not differ significantly between patients with central and peripheral causes. Discordant VOR function according to the stimulus frequency was not uncommon in dizzy patients. Specific patterns of VOR dissociation according to the disease etiologies may offer insight into underlying pathophysiology.