RESUMO
Eukaryotic sexual life cycles alternate between haploid and diploid stages, the transitions between which are delineated by cell fusion and meiotic division. Transcription factors in the TALE-class homeobox family, GSM1 and GSP1, predominantly control gene expression for the haploid-to-diploid transition during sexual reproduction in the unicellular green alga, Chlamydomonas reinhardtii. To understand the roles that GSM1 and GSP1 play in zygote development, we used gsm1 and gsp1 mutants and examined fused gametes that normally undergo the multiple organellar fusions required for the genetic unity of the zygotes. In gsm1 and gsp1 zygotes, no fusion was observed for the nucleus and chloroplast. Surprisingly, mitochondria and endoplasmic reticulum, which undergo dynamic autologous fusion/fission, did not undergo heterologous fusions in gsm1 or gsp1 zygotes. Furthermore, the mutants failed to resorb their flagella, an event that normally renders the zygotes immotile. When gsm1 and gsp1 zygotes resumed the mitotic cycle, their two nuclei fused prior to mitosis, but neither chloroplastic nor mitochondrial fusion took place, suggesting that these fusions are specifically turned on by GSM1/GSP1. Taken together, this study shows that organellar restructuring during zygotic diploidization does not occur by default but is triggered by a combinatorial switch, the GSM1/GSP1 dyad. This switch may represent an ancient mechanism that evolved to restrict genetic recombination during sexual development.
Assuntos
Chlamydomonas reinhardtii/metabolismo , Células Germinativas/metabolismo , Proteínas de Homeodomínio/metabolismo , Proteínas de Plantas/metabolismo , Zigoto/metabolismo , Núcleo Celular/metabolismo , Chlamydomonas reinhardtii/genética , Cloroplastos/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Diploide , Retículo Endoplasmático/genética , Retículo Endoplasmático/metabolismo , Flagelos/genética , Flagelos/metabolismo , Genes Homeobox , Células Germinativas/citologia , Células Germinativas/crescimento & desenvolvimento , Haploidia , Proteínas de Homeodomínio/genética , Mitocôndrias/genética , Mitocôndrias/metabolismo , Fenótipo , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Recombinação Genética , Desenvolvimento Sexual/genética , Zigoto/citologia , Zigoto/crescimento & desenvolvimentoRESUMO
BACKGROUND: Clinical and radiological characteristics of middle cerebral artery (MCA) infarction may differ according to the location of occlusion. OBJECTIVES: We investigated the difference between proximal and distal symptomatic MCA occlusion (MCAO) in patients with ischemic stroke. The factors associated with the imaging characteristics were also analyzed. METHODS: Patients with ischemic stroke due to MCAO were consecutively enrolled. The location of MCAO was determined by the ratio of the length of the ipsilesional MCA to that of the contralateral MCA and dichotomized to proximal and distal MCAO. Clinical and radiological characteristics were compared between patients with proximal and distal MCAO. Factors associated with the basal ganglia (BG) involvement, hemorrhagic transformation (HT), and neurological change during admission were investigated. RESULTS: Among 181 included patients, MCAO location showed a bimodal peak (at the proximal [n = 99] and distal MCA [n = 82]). Proximal MCAO was more frequently associated with hyperlipidemia and large artery atherosclerosis, whereas distal MCAO was more frequently associated with hypertension, atrial fibrillation, and cardioembolic stroke. BG involvement was similar between the 2 groups (48 vs. 39%; p = 0.21), whereas HT was more frequent in distal MCAO (10 vs. 23%; p = 0.02). Among patients with proximal MCAO, hyperintense vessel sign was less frequently observed in those with a BG involvement than those without (38 vs. 60%; p = 0.03). Among those without BG involvement, the presence of HT was very low and similar between patients with proximal and distal MCAOs (1.9 vs. 2.0%). However, in patients with BG involvement, HT was more frequently observed in those with distal MCAO than in those with proximal MCAO (54.8 vs. 15.7%; p < 0.001). The presence of hyperintense vessel sign (OR 0.172, 95% CI 0.051-0.586; p = 0.005) and distal MCAO (OR 0.200, 95% CI 0.059-0.683; p = 0.011) was independently associated with improvement during admission. CONCLUSION: Proximal MCAO is more frequently associated with atherosclerosis, whereas distal MCAO is more frequently associated with cardioembolism. In proximal MCAO, the status of collateral flow presented by hyperintense vessel sign may affect the involvement of BG. In distal MCAO, distal migration of the embolus, which first impacted at the proximal MCA causing BG ischemia, may explain the high rate of HT by reperfusion injury. Hyperintense vessel sign and distal MCAO were independently associated with neurological improvement during admission.
Assuntos
Doenças dos Gânglios da Base/etiologia , Infarto da Artéria Cerebral Média/etiologia , Hemorragias Intracranianas/etiologia , Idoso , Doenças dos Gânglios da Base/diagnóstico por imagem , Doenças dos Gânglios da Base/fisiopatologia , Angiografia Cerebral , Circulação Cerebrovascular , Circulação Colateral , Bases de Dados Factuais , Avaliação da Deficiência , Feminino , Humanos , Infarto da Artéria Cerebral Média/diagnóstico por imagem , Infarto da Artéria Cerebral Média/fisiopatologia , Hemorragias Intracranianas/diagnóstico por imagem , Hemorragias Intracranianas/fisiopatologia , Angiografia por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Fatores de Risco , Grau de Desobstrução VascularRESUMO
Wearable devices may be used to evaluate sleep in patients with obstructive sleep apnoea (OSA). This study compared the use of two wearable devices (the Fitbit Charge 2 (FC2) and Galaxy Watch 2 (GW2)) with that of polysomnography (PSG) for assessing the sleep time of OSA patients. A total of 127 consecutive patients with OSA underwent overnight PSG while wearing the FC2 and GW2 on their nondominant wrist. We compared the total sleep time (TST) determined by the devices with that obtained by PSG with paired t tests, BlandâAltman plots, and interclass correlations. Moreover, we evaluated the time in each sleep stage and differences due to OSA severity. The mean age of the OSA patients was 50 years, and the mean apnoea-hypopnea index was 38.3 events/h. The recording failure rate was not significantly different between the GW2 and FC2 (15.7% vs. 8.7%, p = 0.106). Compared to PSG, both the FC2 and GW2 underestimated TST by 27.5 and 24.9 minutes, respectively. TST bias in both devices did not correlate with OSA severity. The FC2 and GW2 underestimated TST, which should be considered when monitoring sleep time in patients with OSA.
Assuntos
Ritmo Circadiano , Apneia Obstrutiva do Sono , Humanos , Pessoa de Meia-Idade , Polissonografia , Apneia Obstrutiva do Sono/diagnóstico , Sono , Monitores de Aptidão FísicaRESUMO
BACKGROUND AND PURPOSE: Ischemic stroke recurs despite the use of antiplatelet agents. Various mechanisms are involved in recurrence due to intracranial atherosclerosis (ICAS) and extracranial atherosclerosis (ECAS). High-on-aspirin platelet reactivity (HAPR) may differ between recurrent stroke due to ICAS and ECAS. METHODS: Patients with recurrent ischemic stroke as a result of large-artery atherosclerosis despite taking aspirin were enrolled consecutively. Ischemic stroke was classified as stroke due to ICAS or ECAS according to the location of the culprit stenosis. An aspirin reaction units (ARU) value of >550 IU was defined as HAPR. HAPR and its associated factors were compared between the two groups and also considering the mechanism of stroke. RESULTS: Among the 190 patients with recurrent stroke (111 with ICAS and 79 with ECAS), 36 (18.3%) showed HAPR. The ARU value was higher in the ECAS than the ICAS group (492±83 vs. 465±78, mean±standard deviation; p=0.028), as was the proportion of patients with HAPR (27.8% vs. 12.6%, p=0.008). Being male and having stroke due to ECAS (reference=stroke due to ICAS: odds ratio=5.760; 95% confidence interval=2.154-15.403; p<0.001) was independently associated with HAPR. The ARU value differed according to the stroke mechanism, and was highest in those with artery-to-artery embolism. Artery-to-artery embolism was independently associated with HAPR in both the ICAS and ECAS groups. CONCLUSIONS: Recurrent stroke due to ECAS was more strongly associated with HAPR and insufficient antiplatelet inhibition than was that due to ICAS. Artery-to-artery embolism was associated with HAPR in recurrent ischemic stroke as a result of ICAS or ECAS.
RESUMO
BACKGROUND AND PURPOSE: This study aimed to evaluate the efficacy of intra-arterial thrombectomy (IAT) and prognosis for acute ischaemic stroke patients with active cancer. METHODS: We retrospectively reviewed 253 patients who underwent IAT within 24 h after stroke onset between January 2012 and August 2017. We classified the patients into active cancer (n = 26) and control groups (n = 227) and compared clinical data. Primary outcome was a modified Rankin scale score at 3 months with ordinal logistic regression (shift analysis). RESULTS: Initial National Institutes of Health Stroke Scale (NIHSS) and rate of successful recanalisation did not differ between groups, but the active cancer group showed poor outcomes at 3 months on shift analysis (P = 0.001). The independent predictors of poor prognosis were age [adjusted common odds ratio (aOR) 1.03, 95% confidence interval (CI) 1.01-1.05], baseline NIHSS (aOR 1.14, 95% CI 1.09-1.19), baseline C-reactive protein level (aOR 1.14, 95% CI 1.03-1.25), any cerebral haemorrhage (aOR 1.92, 95% CI 1.21-3.06), and active cancer (aOR 2.35, 95% CI 1.05-5.25). Mortality at 90 days was 30.8% in the cancer group and 8.8% in the control group (P = 0.003). CONCLUSIONS: Although baseline characteristics and recanalisation rate after IAT up to 24 h after stroke onset were similar between acute ischaemic stroke patients with active cancer and without any cancer, stroke-related death and short-term outcome were significantly poorer in patients with active cancer than the controls. Post-procedural haemorrhage and active cancer itself were independent predictors of a decrease in functional independence at 3 months.
Assuntos
Isquemia Encefálica/terapia , Artérias Cerebrais , Neoplasias/terapia , Acidente Vascular Cerebral/terapia , Trombectomia/métodos , Idoso , Idoso de 80 Anos ou mais , Isquemia Encefálica/diagnóstico por imagem , Isquemia Encefálica/epidemiologia , Artérias Cerebrais/diagnóstico por imagem , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias/diagnóstico por imagem , Neoplasias/epidemiologia , Estudos Retrospectivos , Acidente Vascular Cerebral/diagnóstico por imagem , Acidente Vascular Cerebral/epidemiologiaRESUMO
Influenza infection increases the risk of ischemic stroke. Here, we represent a case of a 32year-old female who presented with acutely developed altered mental status after influenza A infection. The clinical manifestation and initial lesion on brain DWI mimicked top of basilar syndrome, but without an arterial occlusion or stenosis. Follow-up neuro imaging analysis suggested cerebral venous infarction. It is valuable to report this case of venous infarction in a healthy young adult, as an uncommon complication of adult influenza infection.