Staphylococcus argenteus is a new species that was subclassified from Staphylococcus aureus in 2015, which is difficult to accurately identify by routine testing. Although invasive infections by S. argenteus have been sporadically reported, its detection rate and pathogenicity have not been fully elucidated. Therefore, we attempted to re-identify S. argenteus from the strains detected in blood culture and identified as methicillin-sensitive S. aureus at Kyorin University Hospital from 2016 to 2019, and analyzed toxin-producing genes and drug susceptibility of S. argenteus strains. Of the 312 strains tested, two (0.6%) were re-identified as S. argenteus. Both strains did not have toxin-producing genes and were susceptible to all antimicrobial agents except for penicillin. The detection rate of S. argenteus in blood cultures was lower than that reported in other countries. Further investigation is necessary to elucidate the prevalence and clinical significance of S. argenteus infections in Japan, and development of a simple method for species identification is essential.

We examined the enhanced effect of Fenton reaction by furan fatty acid metabolite, 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid (CMPF) . It is known that CMPF may induce uremia and diabetes, however, its role is not known so far. To evaluate the enhanced effect of Fenton reaction (Fe^2＋＋H₂O₂→･OH＋Fe^3＋＋OH⁻) by CMPF, the breaks of plasmid DNA has been measured using a electrophoresis. It was found that the plasmid DNA was broken by reactive oxygen species -hydroxyl radical (･OH) - accelerated by CMPF. In addition, electron spin resonance shows that CMPF accelerated the ･OH formation from Fenton reaction by reducing Fe^3＋ to Fe^2＋. Furthermore, quantum chemical calculation shows clearly that CMPF forms iron ions to stabilize the chelate complex, however, it does not form copper ion complex. These results suggest that oxidative degradation may be induced by CMPF.

Parathyroid carcinoma is extremely rare and is commonly diagnosed by pathological examination of a surgical specimen after resection for hyperparathyroidism. A 45-year-old woman broke her right clavicle during rehabilitation after undergoing surgery for a right femoral neck fracture. She was diagnosed as having severe osteoporosis and found to have hypercalcemia with high intact parathyroid hormone (PTH) . Thyroid ultrasound examination revealed a large mass (63 × 38 mm) in her cervical area which contained solid and cystic areas. Contrast-enhanced CT revealed the mass lesion was a tumor, the findings being similar to those of thyroid ultrasonography. Methoxy-isobutyl-isomitril scintigraphy showed positive uptake in the mass and the patient was diagnosed as having primary hyperparathyroidism associated with a right parathyroid tumor. Curative resection of the mass, including the right parathyroid and thyroid glands, was performed. The right recurrent nerve was not preserved because the tumor was considered to be invasive. The pathological diagnosis was parathyroid carcinoma. In this report we describe a rare case of a patient with hyperparathyroidism caused by parathyroid carcinoma diagnosed after the patient had experienced multiple bone fractures.