Search

Background: Mycobacterium lentiflavum is a slow-growing nontuberculous mycobacterium that is widely distributed in soil and water systems, but it is sometimes pathogenic to humans. Although cases of M. lentiflavum infections are rare, 22 isolates of M. lentiflavum were identified at a single hospital in Japan. We suspected a nosocomial outbreak; thus, we conducted transmission pattern and genotype analyses. Methods: Cases of M. lentiflavum isolated at Kushiro City General Hospital in Japan between May 2020 and April 2021 were analyzed. The patient samples and environmental culture specimens underwent whole-genome sequencing (WGS). Additionally, we retrospectively collected clinical data from patient medical records. Results: Altogether, 22 isolates of M. lentiflavum were identified from sputum and bronchoalveolar lavage samples. Clinically, the instances with M. lentiflavum isolates were considered contaminants. In the WGS analysis, 19 specimens, including 18 patient samples and 1 environmental culture from the hospital’s faucet, showed genetic similarity. The frequency of M. lentiflavum isolation decreased after we prohibited the use of taps where M. lentiflavum was isolated. Conclusions: WGS analysis identified that the cause of M. lentiflavum pseudo-outbreak was the water used for patient examinations, including bronchoscopy.

Chest wall tumors are relatively rare, and hematogenous metastasis to the chest wall is very rare. We herein describe a rare case of occult thyroid carcinoma as metastasis to the chest wall in an 80-year-old woman. The patient received detailed examinations of the chest wall tumor, and the results suggested that she had occult thyroid carcinoma. Surgery was then performed to remove all of her thyroid. As a result, she was diagnosed with follicular carcinoma of the thyroid. We report an extremely rare case of occult thyroid carcinoma diagnosed as hematogenous metastasis to the chest wall.

Diesel exhaust (DE) is known to be one of the main causes of air pollution. Several studies have suggested that DE causes lung cancer, cardiovascular disease, abnormal reproductive function, and central nervous system damage as well as type I allergy in the airway. Type I allergy also plays a role in pathogenesis of endometriosis. In the present study, we examined the effect of exposure to DE on a rat model of endometriosis. Endometriosis was induced by autotransplantation of endometrium to the peritoneum in female Sprague-Dawley rats exposed to DE during prenatal and postnatal periods. Endometriotic lesions, normal peritoneum, and blood samples were obtained on days 4, 7, and 14 after autotransplantation. The extent of stromal proliferative lesions in the endometriosis model was greater in the rats of the DE exposure group than in those of the control group on day 14. Serum monocyte chemoattractant protein (MCP)-1levelwas significantlyhigher in ratswithendometriosis in the DE exposure group than in those in the control group on day 14. Results of this study suggest that DE exposure enhances the histologic and molecular pathology of endometriosis in rats.

The potential health risks of inhaling nanomaterials are of great concern because of their high specific activity and their unique property of translocation. Earlier studies showed that exposure to nanoparticles through the airway affects both respiratory and extrapulmonary organs. When pregnant mice were exposed to nanoparticles, the respiratory system, the central nervous system and the reproductive system of their offspring were affected. The aim of this study was to assess the effect of maternal exposure to nanoparticles on the offspring, particularly on the kidney. Pregnant ICR mice were exposed to a total of 100 µg of carbon black nanoparticle on the fifth and the ninth days of pregnancy. Samples of blood and kidney tissue were collected from 3-week-old and 12-week-old male offspring mice. Collagen expression was examined by quantitative RT-PCR and immunohistochemistry. Serum levels of creatinine and blood urea nitrogen were examined. Exposure of pregnant ICR mice to carbon black resulted in increased expression of Collagen, type VIII, a1 (Col8a1) in the tubular cells in the kidney of 12-week-old offspring mice but not in 3-week-old ones. The levels of serum creatinine and blood urea nitrogen, indices of renal function, were not different between the groups. These observations were similar to those of tubulointerstitial fibrosis in diabetic nephropathy. These results suggest that maternal exposure to carbon black nanoparticle induces renal abnormalities similar to tubulointerstitial fibrosis in diabetic nephropathy are induced in the kidney of offspring.

The pathogenesis of endometriosis, a gynecologic disorder associated with infertility, appears to involve immune responses. However, the details involved have not been clarified. In this study, we analyzed expression levels of interleukin (IL)-6, IL-10, monocyte chemoattractant protein-1, eosinophil chemotactic protein, macrophage inflammatory protein-1alpha, and regulated on activation normal T cell expressed and secreted (RANTES) and CC chemokine receptor 1 in endometriotic lesions in a rat model in which endometrium is autotransplanted onto peritoneal tissue and found that they were remarkably increased, while those of IL-2, IL-4, and interferon-gamma were not. These results were obtained in a rat model induced by autologous, not allogeneic, transplantation of endometrial epithelium to the peritoneum. Expression of these factors is consistent with that of endometriosis in humans. Therefore, this model may be useful in the investigation of the pathogenesis and treatment of endometriosis.