ACC1-mediated fatty acid biosynthesis intrinsically controls thymic iNKT cell development.

To meet the energetic requirements associated with activation, proliferation, and survival, T cells switch their metabolic signatures from energetically quiescent to activated. However, little is known about the role of metabolic pathway controlling the development of invariant natural killer T (iNKT) cells. In the present study, we found that acetyl-CoA carboxylase 1 (ACC1), a rate-limiting enzyme for the fatty acid biosynthesis pathway, plays an essential role in the development of iNKT cells in the thymus. Mice lacking T-cell specific ACC1 showed a reduced number of iNKT cells with an increased proportion of iNKT cells at immature stages 0 and 1. Furthermore, mixed bone marrow (BM) chimera experiments revealed that T-cell intrinsic ACC1 expression was selectively important for the development of thymic iNKT cells, especially for the differentiation of the NKT1 cell subset. Our single-cell RNA-sequencing (scRNA-seq) data and functional analysis demonstrated that ACC1 is responsible for survival of developing iNKT cells. Thus, these findings highlighted a novel role of ACC1 in controlling thymic iNKT cell development mediated by the control of cell survival.

Clinical Characteristics of Corynebacterium ulcerans Infection, Japan.

Corynebacterium ulcerans is a closely related bacterium to the diphtheria bacterium C. diphtheriae, and some C. ulcerans strains produce toxins that are similar to diphtheria toxin. C. ulcerans is widely distributed in the environment and is considered one of the most harmful pathogens to livestock and wildlife. Infection with C. ulcerans can cause respiratory or nonrespiratory symptoms in patients. Recently, the microorganism has been increasingly recognized as an emerging zoonotic agent of diphtheria-like illness in Japan. To clarify the overall clinical characteristics, treatment-related factors, and outcomes of C. ulcerans infection, we analyzed 34 cases of C. ulcerans that occurred in Japan during 2001-2020. During 2010-2020, the incidence rate of C. ulcerans infection increased markedly, and the overall mortality rate was 5.9%. It is recommended that adults be vaccinated with diphtheria toxoid vaccine to prevent the spread of this infection.

Aurora Image Classification with Deep Metric Learning.

In recent years, neural networks have been increasingly used for classifying aurora images. In particular, convolutional neural networks have been actively studied. However, there are not many studies on the application of deep learning techniques that take into account the characteristics of aurora images. Therefore, in this study, we propose the use of deep metric learning as a suitable method for aurora image classification. Deep metric learning is one of the deep learning techniques. It was developed to distinguish human faces. Identifying human faces is a more difficult task than standard classification tasks because this task is characterized by a small number of sample images for each class and poor feature variation between classes. We thought that the face identification task is similar to aurora image classification in that the number of labeled images is relatively small and the feature differences between classes are small. Therefore, we studied the application of deep metric learning to aurora image classification. As a result, our experiments showed that deep metric learning improves the accuracy of aurora image classification by nearly 10% compared to previous studies.

Usefulness of Fibrinogen/Fibrin Degradation Products Value in Differential Diagnosis Between Acute Ischemic Stroke and Acute Aortic Dissection.

A post-marketing surveillance study reported fatalities following tissue plasminogen activator administration in acute aortic dissection (AAD) with the symptoms of acute ischemic stroke (AIS) patients. Therefore, it is important to discriminate AAD from AIS. The present study aimed to investigate whether fibrinogen/fibrin degradation products (FDP) value can be useful in differential diagnosis between AAD and AIS. The study group comprised 20 AAD patients (10 men and 10 women; age 63.9 ± 13.6 years) and 159 AIS patients (91 men and 68 women; age 74.2 ± 10.6 years) who were transported to our hospital from 2007 to 2012. The AAD cases were further divided into patent-type AAD and thrombosed-type AAD. FDP values were significantly higher in the AAD group than in the AIS group (18.15 [5.2 - 249.9] µg/ml vs. 2.3 [1.5 - 4.45] µg/ml ; P < 0.001). In AAD groups, FDP values were significantly higher in the patent-type AAD group (n = 9) than in the thrombosed type AAD group (n = 11) (293.2 µg/ml [63.1 - 419.6 µg/ml ] vs. 5.6 µg/ml [3.8 - 7.9 µg/ml ]. FDP values were significantly higher in patients with AAD than in those with AIS, especially those with patent-type AAD compared with AIS patients. High FDP values may be a useful marker for differential diagnosis between patent-type AAD and AIS.

A Case of Infectious Enterocolitis with Hyperammonemia.

Case reports of hyperammonemia due to urease-producing bacteria are found occasionally, but most of them are associated with urinary tract infections. We experienced a case of infectious enterocolitis with hyperammonemia in which the causative bacteria was speculated to be urease-producing bacteria. A Japanese woman in her 70s had been diagnosed with microscopic polyangiitis in a nearby hospital and was transferred to our hospital. Although the microscopic polyangiitis was relatively under control after treatment with steroids and rituximab, frequent diarrhea with hyperammonemia (324 µg/dl) appeared and she became comatose. Her blood ammonia decreased to 47 µg/dl and her consciousness recovered to a normal state after antibiotic treatment for infectious enterocolitis and ammonia detoxification therapy. Liver dysfunction, portosystemic shunt, excessive protein intake and constipation were not observed, and she took no medications that would cause hyperammonemia. Although culture results could not identify urease-producing bacteria, considering the clinical course, acute hyperammonemia was suspected to be due to urease-producing bacteria infection. It is necessary to consider the influence of urease-producing bacteria as a cause of acute hyperammonemia not only in urinary tract infections but also in infective enterocolitis.

The first fatal case of Corynebacterium ulcerans infection in Japan.

Introduction.Corynebacterium ulcerans (C. ulcerans) is a zoonotic pathogen that occasionally causes diphtheria-like symptoms in humans. Cases of C. ulcerans infection have been increasing in recent years, and C. ulcerans has been recognized as an emerging pathogen. Case presentation. Here we report a case of asphyxia death due to pseudomembrane caused by diphtheria toxin (DT)-producing C. ulcerans. This is, to our knowledge, the first fatal case of C. ulcerans infection in Japan. A strain of C. ulcerans was obtained from the patient's pet cat and was confirmed to be identical to the patient's isolate by sequencing of the 16S rRNA gene and the DT gene, by pulsed-field gel electrophoresis (PFGE) and by ribotyping. In the same way, it was revealed that the isolate in this case belonged to the same molecular type as the C. ulcerans 0102 isolated from the first case in Japan in a distant prefecture 15 years earlier, in 2001. Conclusion. DT-producing C. ulcerans can be contracted from a companion animal and causes human death if the appropriate treatment is delayed. The finding indicates that this molecular type of virulent C. ulcerans is currently widespread in Japan.

[Examination of relationship between lactate clearance and neurologic outcome in cardiac arrest induced by ventricular fibrillation].

A significant relationship between lactate clearance and mortality rates in cardiac arrest cases has been reported. However, the relationship between lactate clearance and neurologic outcomes in cardiac arrest cases is not clear. We examined lactate clearance in cardiac arrest cases induced by ventricular fibrillation. We investigated 13 patients with cardiac arrest induced by ventricular fibrillation from April, 2006 to March, 2012 in which therapeutic hypothermia was performed. Patients were classified into two groups: those with a favorable neurologic outcome (n=7) and those with a poor outcome (n=6). We compared lactate clearance levels between the two groups. There was no significant difference in lactate concentrations at admission and 8 or 24 hours lactate clearance between the two groups 8 or 24 hours after admission. This result suggests we may not predict the neurologic outcome of cardiac arrest cases induced by ventricular fibrillation using lactate clearance.