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Exon skipping is an efficient technique to inhibit specific gene expression induced by a short-sequence peptide nucleic acid (PNA).To date, there has been no study on the effects of PNA on skin pigmentation. In melanocytes, the tripartite complex is responsible for the transport of mature melanosomes from the nucleus to the dendrites. The tripartite complex is composed of Rab27a, Mlph (Melanophilin), and Myosin Va. Defects in the protein Mlph, a melanosome transport-related protein, are known to cause hypopigmentation. Our study shows that Olipass peptide nucleic acid (OPNA), a cell membrane-permeable PNA, targets exon skipping in the Mlph SHD domain, which is involved in Rab27a binding. Our findings demonstrate that OPNA induced exon skipping in melan-a cells, resulting in shortened Mlph mRNA, reduced Mlph protein levels, and melanosome aggregation, as observed by microscopy. Therefore, OPNA inhibits the expression of Mlph by inducing exon skipping within the gene. These results suggest that OPNA, which targets Mlph, may be a potential new whitening agent to inhibit melanosome movement.
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Background@#The quarantine process at a country's port of entry has an important role in preventing an influx of coronavirus disease 2019 (COVID-19) cases from abroad and further minimizing the national healthcare burden of COVID-19. However, there has been little published on the process of COVID-19 screening among travelers entering into a country.Identifying the characteristics of COVID-19 infected travelers could help attenuate the further spread of the disease. @*Methods@#The authors analyzed epidemiological investigation forms and real-time polymerase chain reaction (PCR) results for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) of entrants to Incheon International Airport between March 11 to April 30, 2020. We performed univariate and multivariate logistic regression analysis to determine the odds of positive SARS-CoV-2 result. @*Results@#A total of 11,074 entrants underwent reverse-transcription PCR for SARS-CoV-2, resulting 388 confirmed cases of COVID-19 infection. COVID-19 had a strong association with the reported loss of smell or taste and association with self-reported fever, chill, cough, and vomiting. If a traveler reported contact with an individual with either respiratory symptoms or confirmed COVID-19 in the last two weeks directly prior to landing, the probability of a positive result was increased. @*Conclusion@#If overseas travelers experience loss of smell or taste in the two weeks prior to arrival, they may require an immediate examination to rule out COVID-19 at a port of entry. As to measure body temperature upon arrival at a port of entry, it is important to screen for any occurrence of fever within the two weeks prior to travel. Also, information with epidemiological relevance, such as recent contact with an individual suffering from any respiratory symptoms or with confirmed COVID-19, should be included in COVID-19 screening questionnaires for international travelers.
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Background@#Depression and anxiety are prevalent and can cause suffering in patients with Parkinson’s disease (PD). The Korean version of the Hospital Anxiety and Depression Scale (K-HADS) has been widely used to assess depression and anxiety symptoms in Korean patient with PD. The present study aimed to assess the reliability and validity of the K-HADS using Rasch measurement analysis. @*Methods@#A total of 106 PD patients (54 males, 52 females) who met the diagnostic criteria of the United Kingdom Brain Bank were recruited. Unidimensionality, the Rasch model fit, response category functioning, patient-item distribution, and the separation reliability of the K-HADS depression (K-HADS-D) and anxiety (K-HADS-A) subscales were statistically evaluated. @*Results@#The mean K-HADS-D and K-HADS-A scores were 8.08±4.69 (mean±standard deviation) and 5.44±4.18, respectively. Cronbach’s α coefficients of the K-HADS-D and K-HADS-A were 0.82 and 0.83. The Rasch analysis revealed that the K-HADS-D and K-HADS-A showed unidimensionality and no disordered functioning was observed in the 4-point polytomous scale. However, both K-HADS-D and K-HADS-A exhibited suboptimal separation reliability, while the K-HADS-A showed inadequate scale targeting with floor effect. @*Conclusions@#The present study comprises the first validation of the K-HADS using the Rasch measurement model, suggesting that the K-HADS-D and K-HADS-A are clinimetrically acceptable and reliable scales for use in Korean patients with PD. However, the moderate person separation indices implicate the relatively low discriminatory ability of the K-HADS in our study patients.
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Background@#Pheochromocytoma and paraganglioma (PPGL) is diagnosed through biochemical confirmation of excessive catecholamines in urine and plasma. Recent technological developments have allowed us to measure urinary free metanephrines; however, the diagnostic accuracy of these new methods and the diagnostic cutoff values have not been evaluated. @*Methods@#This is a retrospective study of 595 subjects, including 71 PPGL cases and 524 controls. PPGL was based on pathological confirmation. Subjects with no evidence of PPGL over 2 years were included in the control group. @*Results@#Urinary free metanephrines yielded similar area under the curve (AUC) to urinary fractionated metanephrines and plasma free metanephrines. However, urinary free normetanephrine yielded a better AUC than did urinary fractionated normetanephrine. The optimal cutoff for urinary free metanephrine and normetanephrine corrected for urinary creatinine yielded 97.2% sensitivity and 98.1% specificity. @*Conclusion@#Urinary free metanephrines are a reliable method for diagnosing PPGL in Asian populations compared with existing biochemical methods.
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Background@#Pheochromocytoma and paraganglioma (PPGL) is diagnosed through biochemical confirmation of excessive catecholamines in urine and plasma. Recent technological developments have allowed us to measure urinary free metanephrines; however, the diagnostic accuracy of these new methods and the diagnostic cutoff values have not been evaluated. @*Methods@#This is a retrospective study of 595 subjects, including 71 PPGL cases and 524 controls. PPGL was based on pathological confirmation. Subjects with no evidence of PPGL over 2 years were included in the control group. @*Results@#Urinary free metanephrines yielded similar area under the curve (AUC) to urinary fractionated metanephrines and plasma free metanephrines. However, urinary free normetanephrine yielded a better AUC than did urinary fractionated normetanephrine. The optimal cutoff for urinary free metanephrine and normetanephrine corrected for urinary creatinine yielded 97.2% sensitivity and 98.1% specificity. @*Conclusion@#Urinary free metanephrines are a reliable method for diagnosing PPGL in Asian populations compared with existing biochemical methods.
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Background@#and PurposeWe aimed to determine the patterns and mechanisms of persistent nystagmus (PN) lasting >1 year in lateral medullary infarction (LMI). @*Methods@#We recruited 13 patients with PN due to LMI and another 13 with transient nystagmus (TN) (<1 year) as control. All patients underwent oculography, rotatory chair test, caloric test, bedside head impulse test, dizziness handicap inventory (DHI), and brain MRI. @*Results@#All patients had spontaneous, contralesional, horizontal-torsional nystagmus during the acute phase. Although two patients exhibited consistent contralesional torsional nystagmus, most patients (11/13, 85%) with PN evolved from the initial contralesional to ipsilesional nystagmus. During horizontal gaze, the patterns of ipsilesional PN were diverse; torsional (n=5), torsional-downbeat (n=2), horizontal (n=2), and horizontal nystagmus while looking at the lesion side, and torsional nystagmus while looking at the opposite side (n=2). During rotatory chair test, the gains of the vestibulo-ocular reflex in the PN group were lower than those in the TN group to the lesion side at 0.02 and 0.64 Hz. The caudal and ventrolateral parts of the vestibular nuclei were mostly involved in patients with PN. The DHI score did not differ between the groups. @*Conclusions@#PN patterns frequently change in LMI. Resultant vestibular asymmetry after vestibular afferents or cerebellar inhibitory pathway damage and/or inappropriate vestibular compensation may be responsible for PN in LMI. Impairment of the horizontal or vertical neural integrators may be another cause. The presence of PN does not necessarily indicate more severe dizziness in LMI.
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BACKGROUND@#Differential diagnosis of idiopathic Parkinson disease (IPD) and multiple system atrophy-Parkinson type (MSA-P) is challenging since they share clinical features with parkinsonism and autonomic dysfunction. To distinguish MSA-P from IPD when the symptoms are relatively mild, we investigated the usefulness of the quantitative fractionalized autonomic indexes and evaluated the correlations of autonomic test indexes and functional status.@*METHODS@#Thirty-six patients with parkinsonism (22 with IPD and 14 with MSA-P) in Soonchunhyang University Bucheon Hospital from February 2014 to June 2015 were prospectively enrolled in the study. We compared fractionalized autonomic indexes and composite autonomic scoring scale between patients with IPD and MSA-P with Hoehn and Yahr (H&Y) score ≤3. Parasympathetic indexes included expiratory/inspiratory ratio during deep breathing, Valsalva ratio (VR), and regression slope of systolic blood pressure (BP) in early phase II (vagal baroreflex sensitivity) during Valsalva maneuver. Sympathetic adrenergic indexes were pressure recovery time (PRT) and adrenergic baroreflex sensitivity (BRSa) (BP decrement associated with phase 3 divided by the PRT), sympathetic index 1, sympathetic index 3, early phase II mean BP drop, and pulse pressure reduction rate. Additionally, we compared the unified multiple system atrophy rating scale (UMSARS) and H&Y scores and the autonomic indexes in all patients.@*RESULTS@#PRT was significantly different between the IPD and MSA-P groups (P = 0.004) despite the similar BP drop during tilt. Cut-off value of PRT was 5.5 s (sensitivity, 71.4%; specificity, 72.7%). VR (r = -0.455, P = 0.009) and BRSa (r = -0.356, P = 0.036) demonstrated a significant correlation with UMSARS and H&Y scores.@*CONCLUSIONS@#Among the cardiovascular autonomic indexes, PRT can be a useful parameter in differentiating the early stage of MSA-P from that of IPD. Moreover, VR, and BRSa may be the optimal indexes in determining functional symptom severity.
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Background@#Differential diagnosis of idiopathic Parkinson disease (IPD) and multiple system atrophy-Parkinson type (MSA-P) is challenging since they share clinical features with parkinsonism and autonomic dysfunction. To distinguish MSA-P from IPD when the symptoms are relatively mild, we investigated the usefulness of the quantitative fractionalized autonomic indexes and evaluated the correlations of autonomic test indexes and functional status.@*Methods@#Thirty-six patients with parkinsonism (22 with IPD and 14 with MSA-P) in Soonchunhyang University Bucheon Hospital from February 2014 to June 2015 were prospectively enrolled in the study. We compared fractionalized autonomic indexes and composite autonomic scoring scale between patients with IPD and MSA-P with Hoehn and Yahr (H&Y) score ≤3. Parasympathetic indexes included expiratory/inspiratory ratio during deep breathing, Valsalva ratio (VR), and regression slope of systolic blood pressure (BP) in early phase II (vagal baroreflex sensitivity) during Valsalva maneuver. Sympathetic adrenergic indexes were pressure recovery time (PRT) and adrenergic baroreflex sensitivity (BRSa) (BP decrement associated with phase 3 divided by the PRT), sympathetic index 1, sympathetic index 3, early phase II mean BP drop, and pulse pressure reduction rate. Additionally, we compared the unified multiple system atrophy rating scale (UMSARS) and H&Y scores and the autonomic indexes in all patients.@*Results@#PRT was significantly different between the IPD and MSA-P groups (P = 0.004) despite the similar BP drop during tilt. Cutoff value of PRT was 5.5 s (sensitivity, 71.4%; specificity, 72.7%). VR (r = -0.455, P = 0.009) and BRSa (r = -0.356, P = 0.036) demonstrated a significant correlation with UMSARS and H&Y scores.@*Conclusions@#Among the cardiovascular autonomic indexes, PRT can be a useful parameter in differentiating the early stage of MSAP from that of IPD. Moreover, VR, and BRSa may be the optimal indexes in determining functional symptom severity.
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OBJECTIVES: Fall is a major cause of morbidity and mortality among older adults. Falls result from many various causes, and dizziness is important risk for falls, especially in the elderly. Research on the relationship between chronic dizziness and falls in elderly people has been rarely performed and these were no studies that analyzed the risk of falls according to subtypes of chronic dizziness. METHODS: We conducted a prospective study of the association between subtypes of chronic dizziness and falls in the elderly between 65 to 75 years. We divided dizzy patients into 5 groups according to the results of symptom, vestibular and autonomic function test. Falls and new events (acute dizziness or other medical conditions) were checked monthly by telephone or out patient department follow-up for 6 months. RESULTS: Thirty-four patients were enrolled and all completed follow-up for 6 months. Nine patients classified as the falling groups and 34 patients as nonfalling group. Whereas the frequencies of orthostatic hypotension (n=6, 67%) and vestibular dysfunction (n=1, 11%) were higher in fall group, psychogenic dizziness (n=12, 35%), and vestibular migraine (n=3, 9%) were more frequent in nonfall group. CONCLUSIONS: The presence of dizziness in the elderly is a strong predictor of fall, especially orthostatic hypotension is an important predictor of fall. In order to lower the risk of falls in the elderly, an approach based on the cause of dizziness is needed.
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Adulto , Idoso , Humanos , Acidentes por Quedas , Classificação , Tontura , Seguimentos , Hipotensão Ortostática , Transtornos de Enxaqueca , Mortalidade , Estudos Prospectivos , TelefoneRESUMO
OBJECTIVES: The Korean Dizziness Handicap Inventory (KDHI), which includes 25 patient-reported items, has been used to assess self-reported dizziness in Korean patients with Parkinson disease (PD). Nevertheless, few studies have examined the KDHI based on item-response theory within this population. The aim of our study was to address the feasibility and clinimetric properties of the KDHI instrument using polytomous Rasch measurement analysis. METHODS: The unidimensionality, scale targeting, separation reliability, item difficulty (severity), and response category utility of the KDHI were statistically assessed based on the Andrich rating scale model. The utilities of the orderedresponse categories of the 3-point Likert scale were analyzed with reference to the probability curves of the response categories. The separation reliability of the KDHI was assessed based on person separation reliability (PSR), which is used to measure the capacity to discriminate among groups of patients with different levels of balance deficits. RESULTS: Principal component analyses of residuals revealed that the KDHI had unidimensionality. The KHDI had satisfactory PSR and there were no disordered thresholds in the 3-point rating scale. However, the KDHI showed several issues for inappropriate scale targeting and misfit items (items 1 and 2) for Rasch model. CONCLUSIONS: The KDHI provide unidimensional measures of imbalance symptoms in patients with PD with adequate separation reliability. There was no statistical evidence of disorder in polytomous rating scales. The Rasch analysis results suggest that the KDHI is a reliable scale for measuring the imbalance symptoms in PD patients, and identified parts for possible amendments in order to further improve the linear metric scale.
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Humanos , Tontura , Doença de Parkinson , Análise de Componente Principal , Pesos e MedidasRESUMO
Cerebellar ataxia with neuropathy and vestibular areflexia syndrome (CANVAS) is a slowing progressive ataxic disorder characterized by bilateral vestibulopathy, cerebellar ataxia and somatosensory impairment. Autonomic dysfunction is recently considered as a core feature in CANVAS in addition to these symptoms. In most cases, patients with CANVAS show cerebellar atrophy in brain imaging, but some cases show minimal or no atrophy of cerebellum. Brain (18F)-fluoro-2-deoxy-D-glucose positron emission tomography (¹⁸F-FDG PET) study can be a complimentary tool to diagnosis CANVAS in cases of no structural abnormality such as cerebellar atrophy. Hereby, we present a case of CANVAS with minimal atrophy of cerebellum but showing a prominent hypometabolism in cerebellum, thalamus and posterior cingulate cortex in ¹⁸F-FDG PET.
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Humanos , Atrofia , Encéfalo , Ataxia Cerebelar , Cerebelo , Diagnóstico , Giro do Cíngulo , Neuroimagem , Tomografia por Emissão de Pósitrons , Disautonomias Primárias , Tálamo , Neuronite VestibularRESUMO
The original version of this article contained wrong informations of some authors which should be changed.
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BACKGROUND AND PURPOSE: Nonmotor symptoms (NMS) in Parkinson's disease (PD) have multisystem origins with heterogeneous manifestations that develop throughout the course of PD. NMS are increasingly recognized as having a significant impact on the health-related quality of life (HrQoL). We aimed to determine the NMS presentation according to PD status, and the associations of NMS with other clinical variables and the HrQoL of Korean PD patients. METHODS: We surveyed patients in 37 movement-disorders clinics throughout Korea. In total, 323 PD patients were recruited for assessment of disease severity and duration, NMS, HrQoL, and other clinical variables including demographics, cognition, sleep scale, fatigability, and symptoms. RESULTS: In total, 98.1% of enrolled PD subjects suffered from various kinds of NMS. The prevalence of NMS and scores in each NMS domain were significantly higher in the PD group, and the NMS worsened as the disease progressed. Among clinical variables, disease duration and depressive mood showed significant correlations with all NMS domains (p<0.001). NMS status impacted HrQoL in PD (rS=0.329, p<0.01), and the association patterns differed with the disease stage. CONCLUSIONS: The results of our survey suggest that NMS in PD are not simply isolated symptoms of degenerative disease, but rather exert significant influences throughout the disease course. A novel clinical approach focused on NMS to develop tailored management strategies is warranted to improve the HrQoL in PD patients.
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Humanos , Cognição , Demografia , Coreia (Geográfico) , Transtornos dos Movimentos , Doença de Parkinson , Prevalência , Qualidade de VidaRESUMO
A hyperintensity in the subarachnoid space on fluid-attenuated inversion-recovery (FLAIR) images is often caused by diseases such as subarachnoid hemorrhage or meningitis. Oxygen has a known paramagnetic effect and also causes signal changes in the subarachnoid space on FLAIR images. These changes usually develop when the inspired air contains a high oxygen fraction. Here we present a patient with a hyperintensity in the subarachnoid space on FLAIR images whose inspired air contained only a low oxygen fraction.
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Humanos , Meningite , Oxigênio , Hemorragia Subaracnóidea , Espaço SubaracnóideoRESUMO
Lemierre's syndrome is characterized by anaerobic bacterial infection in the head and neck, causing thrombophlebitis of the jugular vein. This disease is usually associated with a history of pharyngitis. The most common pathogens are Fusobacterium species, particularly Fusobacterium necrophorum. Lemierre's syndrome is seen most commonly in teenagers and young adults. We present a case report of a 67-year-old man with an atypical clinical manifestation of an uncommon pathogen in Lemierre's syndrome with epilepsia partialis continua.
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Adolescente , Idoso , Humanos , Adulto Jovem , Infecções Bacterianas , Epilepsia Parcial Contínua , Fusobacterium , Fusobacterium necrophorum , Cabeça , Veias Jugulares , Síndrome de Lemierre , Pescoço , Faringite , Tromboflebite , Trombose VenosaRESUMO
Fucoidan has attracted attention as a potential drug because of its biological activities, which include osteogenesis. However, the molecular mechanisms involved in the osteogenic activity of fucoidan in human alveolar bone marrow-derived mesenchymal stem cells (hABM-MSCs) remain largely unknown. We investigated the action of fucoidan on osteoblast differentiation in hABM-MSCs and its impact on signaling pathways. Its effect on proliferation was determined using the crystal violet staining assay. Osteoblast differentiation was evaluated based on alkaline phosphatase (ALP) activity and the mRNA expression of multiple osteoblast markers. Calcium accumulation was determined by Alizarin red S staining. We found that fucoidan induced hABM-MSC proliferation. It also significantly increased ALP activity, calcium accumulation and the expression of osteoblast-specific genes, such as ALP, runt-related transcription factor 2, type I collagen-alpha 1 and osteocalcin. Moreover, fucoidan induced the expression of bone morphogenetic protein 2 (BMP2) and stimulated the activation of extracellular signal-related kinase (ERK), c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase by increasing phosphorylation. However, the effect of fucoidan on osteogenic differentiation was inhibited by specific inhibitors of ERK (PD98059) and JNK (SP600125) but not p38 (SB203580). Fucoidan enhanced BMP2 expression and Smad 1/5/8, ERK and JNK phosphorylation. Moreover, the effect of fucoidan on osteoblast differentiation was diminished by BMP2 knockdown. These results indicate that fucoidan induces osteoblast differentiation through BMP2-Smad 1/5/8 signaling by activating ERK and JNK, elucidating the molecular basis of the osteogenic effects of fucoidan in hABM-MSCs.
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Humanos , Proteína Morfogenética Óssea 2/genética , Cálcio/metabolismo , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Relação Dose-Resposta a Droga , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Células-Tronco Mesenquimais/citologia , Osteoblastos/citologia , Osteogênese/efeitos dos fármacos , Fosforilação , Polissacarídeos/farmacologia , Inibidores de Proteínas Quinases/farmacologia , RNA Mensageiro/genética , Transdução de Sinais/efeitos dos fármacos , Proteínas Smad/metabolismoRESUMO
OBJECTIVE: There have been several efforts to elucidate the pathophysiology of the vestibular migraine (VM). But, there is no consistent result. This study was to identify the possible pathophysiology of VM by comparing vestibulo-ocular reflex (VOR) parameters between VM, and the tension type headache (TTH) patients. In addition, we compared VOR parameters between ictal and interictal period in the VM group. METHODS: Seventy eight patients were included: 44 having VM and 34 TTH. Three parameters (gain, asymmetry, and phase) of the horizontal VOR rotating at 60 degrees were measured. In 10 VM patients VOR parameters were obtained twice sequentially first in the ictal and second in the interictal period. RESULTS: Although the average of the VOR gain in VM group was lower than that of TTH group but there was no statistical significance. An asymmetry of the VOR was significantly higher in VM group. There were various changes in other VOR parameters between ictal and interictal periods with no consistent trends. CONCLUSION: We could deduce that VM patients might have subclinical vestibular dysfunction from the reduced gain and increased asymmetry of the VOR in the interictal period. Dynamic changes of the VOR in the ictal period could be responsible for dizziness in VM patients, which are caused by the pathological alteration of the physiologic plasticity of the VOR.
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Humanos , Tontura , Transtornos de Enxaqueca , Plásticos , Reflexo Vestíbulo-Ocular , Cefaleia do Tipo Tensional , Testes de Função VestibularRESUMO
BACKGROUND AND OBJECTIVES: Dizziness is a common presenting complaint in the emergency department (ED) that had various pathologic causes. Most of dizziness can be caused by benign origin but identifying cerebrovascular causes among ED patients with dizziness is a diagnostic challenge. ABCD2 score is clinical prediction tool for assessing the risk of stroke after a transient ischemic attack. We evaluated predictors of cerebrovascular causes and whether ABCD2 score would identify cerebrovascular events among ED patients with dizziness. MATERIALS AND METHODS: We analyzed 180 patients (> or =20 years old) with dizziness in ED, Presbyterian Medical Center (single-center prospective observational study) for 2 months. Type of dizziness, associated symptoms, past medical history, ABCD2 score (0-7), neuro-otologic examination, diagnosis were recorded. RESULTS: The incidence of dizziness is 3.6% (192/5,374). After excluding 12 patients, 180 patients (56% female, mean 59 years) met our eligibility criteria and were included in the final analysis. Cerebrovascular causes of dizziness were found in 10% (18/180): 3 vertebrobasilar insufficiency, 9 cerebellar infarction, 1 right middle cerebral artery (MCA) infarction, 1 right MCA giant aneurysm, 1 lateral medullary infarction, 1 posterior limb of internal capsule infarction, 1 intracerebral hemorrhage of cerebellum. Patients with cerebrovascular cause were males and had more hypertension, diabetes mellitus, imbalance, abnormal neuro-otologic findings and ABCD2 score. CONCLUSION: Several clinical factors (hypertension, diabetes, abnormal neuro-otologic findings ABCD2 scores) favored a diagnosis of central neurological causes of dizziness. ABCD2 score is a simple and easily applied tool for distinguishing cerebrovascular from peripheral causes of dizziness in ED.
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Feminino , Humanos , Masculino , Aneurisma , Cerebelo , Hemorragia Cerebral , Diabetes Mellitus , Diagnóstico , Tontura , Medicina de Emergência , Serviço Hospitalar de Emergência , Extremidades , Hipertensão , Incidência , Infarto , Cápsula Interna , Ataque Isquêmico Transitório , Artéria Cerebral Média , Estudos Prospectivos , Protestantismo , Acidente Vascular Cerebral , Insuficiência VertebrobasilarRESUMO
BACKGROUND: Natural killer cells expanded from human peripheral blood (PB) have been used in cancer immunotherapy research. Although most research teams have access to human PB, it is necessary to find a source of blood that can be easily obtained. We have tested the possibility of using blood retained in a disposable platelet apheresis set as an alternative source, with special interest in expansion of NK cells for use in cancer immunotherapy research. METHODS: For expansion of NK cells, peripheral blood mononuclear cells (PBMCs) were isolated from an MCS+ platelet apheresis kit (Haemonetics, Braintree, USA) and PB from the same donor (n=7) and co-cultured with 100-Gy gamma ray-irradiated K562 cells expressing the 4-1BB ligand and membrane-bound IL-15 for three weeks in RPMI1640 medium in the presence of IL-2 and IL-15. Cytotoxicity was measured using WST-1 at 1:1, 2:1, and 4:1 effector-to-target (E:T) ratios for a period of four hours. RESULTS: Mean rate of expansion of NK cells was 1,097-fold and their purity was 94.4% from blood retained in a disposable platelet apheresis set; mean rate of expansion of NK cells was 953-fold and their purity was 92.0% from PB after a period of three weeks. No differences in cytotoxicity against K562, 697, Raji, and RPMI8226 were observed between NK cells expanded from two blood sources. CONCLUSION: Blood retained in a disposable platelet apheresis set is a useful and convenient source for expansion of NK cells for use in cancer immunotherapy research.