Microglia are the resident macrophages of the central nervous system and play complex roles in the milieu of diseases including the primary diseases of myelin. Although mitochondria are critical for cellular functions and survival in the nervous system, alterations in and the roles of mitochondrial dynamics and associated signaling in microglia are still poorly understood. In the present study, by combining immunohistochemistry and 3D ultrastructural analyses, we show that mitochondrial fission/fusion in reactive microglia is differentially regulated from that in monocyte-derived macrophages and the ramified microglia of normal white matter in myelin disease models. Mouse cerebral microglia in vitro demonstrated that stimulation of TLR4 with lipopolysaccharide, widely used to examine microglial reactions, caused the activation of the mitochondrial fission protein, dynamin-related protein 1 (Drp1) and enhanced production of reactive oxygen species (ROS). The increase in the ROS level activated 5′ adenosine monophosphate-activated protein kinase (AMPK), and facilitated elongation of mitochondria along the microtubule tracks. These results suggest that the polymorphic regulation of mitochondrial fission and fusion in reactive microglia is mediated by distinct signaling under inflammatory conditions, and modulates microglial phenotypes through the production of ROS.
Dysphagia, one of the major complications of neuromuscular diseases such as Parkinson's disease and amyotrophic lateral sclerosis (ALS), decreases quality of life and may lead to malnutrition or aspiration pneumonia. Although recent reports have suggested that surgical aspiration prevention improves quality of life and enables oral intake, the selection of appropriate aspiration prevention techniques has rarely been discussed. In this report, we present the cases of three patients with neuromuscular diseases who underwent surgical aspiration prevention; we selected the surgical techniques based on analysis of the dysphagia mechanisms, disease progression, and general condition in each case. Case 1 was a 55-year-old man with multiple system atrophy (MSA) and presented with dysphagia associated with insufficient upper esophageal sphincter (UES) relaxation. We performed central-part laryngectomy, which was able to improve UES relaxation. Case 2 was a 79-year-old man with progressive supranuclear palsy who presented with respiratory disorder and dysphagia. Glottic closure under local anesthesia was selected because he also had acute hepatobiliary dysfunction and methicillin-resistant Staphylococcus aureus pneumonia with pleural effusion. Case 3 was a 75-year-old man with ALS and presented with respiratory disorder and mild dysphagia. Subglottic closure with total cricoidectomy was selected because his dysphagia was expected to worsen due to tracheostomy and disease progression. We also summarize the characteristics of the aspiration prevention surgical techniques based on our cases and on literature review. The causes of dysphagia, including insufficient UES opening during swallowing, weak pharyngeal constriction, velopharyngeal insufficiency, and inadequate laryngeal elevation, should be assessed by detailed examination before surgery, and the type of aspiration prevention surgery should be selected based on patient swallowing function and general condition.
Ultrastructural analyses with electron microscopy have provided indispensable information to understand physiology and pathology of the nervous system. Recent advancement in imaging methodology paved the way for complete reconstruction of the neuronal connection map in the central nervous system, which is termed 'connectome' and would provide key insights to understand the functions of the brain. The critical advancement includes serial ultrastructural observation with scanning electron microscopy (SEM) instead of conventional serial sectioning transmission electron microscopy along with specific tissue preparation methods to increase heavy metal deposition for efficient SEM imaging. The advanced imaging methods using SEM have distinct advantages and disadvantages in multiple aspects, such as resolution and imaging speed, and should be selected depending on the observation conditions, such as target tissue sizes, required spatial resolution and necessity for re-observation. Dealing with the huge dataset remained to be a major obstacle, and automation in segmentation and 3D reconstruction would be critical to understand neuronal circuits in a larger volume of the brain. Future improvement in acquisition and analyses of the morphological data obtained with the advanced SEM imaging is awaited to elucidate the significance of whole connectome as the structural basis of the consciousness, intelligence and memory of a subject.
Advancement of microscopic technologies established significant progress in our understanding of the brain. In the recent effort to elucidate the complete wiring map of the brain circuitry termed 'connectome', the different modalities of imaging technology, including those of light and electron microscopy, have started providing essential contribution in multiple organisms. The contribution would be impossible without the recent innovation in both acquisition and analyses of the big connectomic data. The current data demonstrated complicated networks with unidirectional and reciprocal connections of the cerebral circuits at the macroscopic and light microscopic ('mesoscopic') levels, and the unimaginable complexity of synaptic connections between axons and dendrites at the electron microscopic ('microscopic') level. At the same time, the data highlighted the necessity to make substantial advancement in methodology of the connectomic studies, including efficient handling and automated analyses of the acquired dataset. Further understanding about structural and functional connectome seems to be facilitated by combinations of the different imaging modalities. Such multidisciplinary approaches will give us the clues to address whether the complete connectome can elucidate fundamental mechanisms processing the basic and higher functions of human brains.
Background: Anaplastic thyroid cancer is a rare and rapidly progressive cancer with an extremely poor prognosis. Besides surgical control, no clear treatment has been found, mainly due to the small population affected and high mortality rate.Aims: To propose evidence-based treatment guidelines based on a 5-year retrospective study of patients with anaplastic thyroid cancer treated at our facility. There have been no clearly defined guidelines for treatment plan for undifferentiated thyroid cancer. Our paper presents a retrospective analysis on the treatment of patients with undifferentiated thyroid cancer at our hospital. Methods and Results: We retrospectively evaluated the data of patients diagnosed with anaplastic thyroid cancer from April 2017 to March 2022. The total number of patients diagnosed and treated was seven. Two of these patients had operable cancer; five were inoperable and treated with lenvatinib or paclitaxel maintenance therapy. The median time from the first visit to death was 3.84 months, and six of the seven patients died before this study started. Three of them had Stage IVB cancer and died due to deterioration of their general condition, including lung metastasis; the other three had Stage IVC cancer and died of suffocation. The survivor had Stage IVB cancer, was treated by surgery combined with chemical radiotherapy, and survived >240 days. Conclusion: Considering the above findings, personalized surgical treatment should be prioritized to prevent suffocation. Especially in Stage IVB cancer, local control can be achieved by surgical and anticancer drug treatment to avoid death from suffocation.
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