Mankind has achieved remarkable social development following the Industrial Revolution. Then, we have depended on fossil fuels for much of its energy needs. As a result, a global warming caused by the massive consumption of fossil fuels has recently come up to the surface. And the number of natural disasters caused by it is on the increase. In this background, a Stirling engine has attracted attention because of an ability to utilize a wide variety of heat source which were previously unused.
Pancreatic solid pseudopapillary neoplasm (SPN) is a low-grade malignant neoplasm with a good prognosis. Clinically aggressive SPNs have rarely been reported but have not been analyzed in detail. In this study, we referred to this highly malignant type of SPN as high-grade SPN (HG-SPN) and compared its clinicopathological and genetic characteristics with conventional SPN (C-SPN) using immunohistochemistry and gene panel analyses. Five HG-SPNs and 15 C-SPNs were evaluated in this study. HG-SPNs share many pathologic characteristics: macroscopically, solid/cystic appearances, microscopically, pseudopapillary/pseudorosette pattern (100%), tumor cell loose cohesiveness (100%), thin/delicate vasculature (100%), tumor cell cytoplasmic vacuolization (100%), immunohistochemical positivity for β-catenin (nuclear expression) (100%), CD10 (80%), CD56 (80%), and vimentin (100%). Conversely, HG-SPNs showed distinct malignant features compared with C-SPNs: mean tumor size (11.7 vs. 2.9 cm, P <0.001); true necrosis (100% vs. 0%, P <0.001); high-grade nuclear atypia (100% vs. 0%, P <0.001); lymphatic and/or venous invasion (100% vs. 20%, P =0.004); mean mitotic count (4.38 vs. 0.05/high-power field, P <0.001); and mean Ki-67 labeling index (33.9% vs. 3.4%, P <0.001). All HG-SPN patients died of primary disease 3 to 36 months after surgery, while all C-SPN patients were alive without disease. Genetic studies have shown that all analyzed HG-SPNs have CTNNB1 mutations. Two HG-SPN cases showed RB1 mutations with altered immunohistochemical findings for RB1 and p16. Two HG-SPN cases had TP53 mutation and/or p53 overexpression. In conclusion, HG-SPNs show distinct malignant features and some genetic alterations that differ from C-SPNs, indicating the importance of differentiating between these 2 subtypes.
Pachydermodactyly, an uncommon variant of digital fibromatosis, predominantly affects young men and results in fibrous swelling on the sides of the proximal interphalangeal joints. It is generally considered benign and asymptomatic, requiring only regular follow-up. Nevertheless, the absence of established diagnostic criteria has led to misdiagnoses, prompting the administration of unnecessary medications. In this report, we present a 14-year-old Japanese male with symptomatic pachydermodactyly, necessitating careful differentiation from juvenile idiopathic arthritis (JIA) due to the presence of morning stiffness. Despite exhibiting typical pachydermodactyly features, the patient's age and symptoms suggested rheumatoid factor-negative polyarticular JIA. However, the lack of inflammatory findings precluded a JIA diagnosis. Following confirmation of the absence of uveitis and progression of bone destruction, the morning stiffness spontaneously resolved without active treatment. However, the patient underwent surgery for aesthetic reasons to alleviate the persistent swelling. Our case highlights the nuances of symptomatic pachydermodactyly, with a literature review revealing similarities between symptomatic and asymptomatic cases. This challenges the suitability of asymptomatic status as a definitive diagnostic criterion. Our findings contribute to the ongoing efforts in establishing diagnostic criteria for pachydermodactyly, aiming to reduce misdiagnoses and unnecessary medications in patients.
Stirling engines do not necessarily require the combustion of fossil fuels and are therefore attracting attention as heat engines that can use a wide variety of fuels and as low-pollution equipment. Therefore, the Stirling engine is expected to be put to practical use in areas where it is difficult to utilize internal combustion engines, such as solar heat and factory waste heat. The aim of this study is to design and build a prototype Stirling engine that can be operated using low-temperature heat sources such as snow and ice. In the prototype engine, the bore of the power piston was changed to a smaller bore and experiments were carried out and discussed. As a result, it was confirmed that the continuous operation time could be improved and that the engine could be operated at a temperature difference of about 30°C. Based on these results, a larger Stirling engine using a low-temperature heat source and a non-contact power generation method will be investigated to increase the power output.
Since the Industrial Revolution, the mankind has achieved astonishing technological innovation and economic development. Recently, the environmental pollution and global warming caused by a large amount of consumption of fossil fuels have become apparent. From such a background the Sustainable Development Goals (SDGs), which include climate change measures, were adopted at the UN Summit in 2015. On the other hand, Japan's energy self-sufficiency rate is 11.8%, which is low among developed countries, and Japan is dependent on imports of most fossil fuels from other countries. Besides the Stirling engines is not necessarily require the combustion of fossil fuels and is therefore low polluting. From this point, the Stirling engines attracts, attention in recent years. But one of the problems preventing the practical use of the Stirling engine is that it is more difficult to miniaturize than a conventional internal combustion engine. Another disadvantage is that the output response is poor. In this study, we focused on the Stirling engine as an engine that uses renewable energy and designed and manufactured a Stirling engine that can be operated even when snow or ice is used as the low-temperature heat source. And, we use a room temperature as the high-temperature heat source. The aim of this research is to make effective use of low-temperature heat sources that have not been used until now.
Epithelial-myoepithelial carcinoma (EMC) is a rare salivary gland cancer characterized by biphasic tubular structures composed of inner ductal and outer clear myoepithelial cells. Because of its histologic variety and overlap of histologic features with other salivary gland tumors, there are broad differential diagnoses. The HRAS Q61R mutation has been reported to be frequent in and specific to EMC. We evaluated the usefulness of RAS Q61R mutant-specific immunohistochemical (IHC) staining for detecting this genetic alteration in EMC. We investigated 83 EMC cases and 66 cases of salivary gland tumors with an EMC-like component, including pleomorphic adenoma, adenoid cystic carcinoma, basal cell adenoma/adenocarcinoma, and myoepithelial carcinoma. Sanger sequencing was performed for HRAS , KRAS , and NRAS . The diffuse and membranous/cytoplasmic RAS Q61R IHC expression was observed in 65% of EMC cases, in which all cases harbored the HRAS Q61R mutation. IHC-positive cases were present only in de novo EMCs (54/76 cases, 71%) but not in EMCs ex pleomorphic adenoma. The immunoreactivity was almost always restricted to the myoepithelial cells. Conversely, all EMC cases lacking the HRAS Q61R mutation were negative on IHC. In addition, only 3% of EMC-like tumors showed the abovementioned immunopositivity. None of the cases examined carried KRAS or NRAS mutations. IHC for RAS Q61R is highly sensitive and specific for detecting the HRAS Q61R mutation in EMC. Since significant immunopositivity was almost exclusively identified in nearly two thirds of EMCs but seldom in the histologic mimics, the IHC of RAS Q61R is a useful tool for diagnosing EMC in general pathology laboratories.
A 31-year-old man with neurofibromatosis type 1 (NF-1) had undergone resection of a malignant peripheral nerve sheath tumor (MPNST) on the buttock 3 months previously. He subsequently underwent mechanical thrombectomy for a hyperacute left middle cerebral artery embolism. Histopathologically, the emboli comprised neurofilament-positive pleomorphic tumor cells with geographic necrosis and conspicuous mitosis and were identified as MPNST. The patient died of respiratory failure due to lung MPNST metastasis on day 15 of hospitalization. To our knowledge, this is the first report of a spontaneous cerebral embolism due to MPNST in a NF-1 patient.
