Publications by authors named "Ryuichiro Hori"

2 Publications

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Clarithromycin As an Alternative and Prophylactic Agent in a Hematopoietic Stem Cell Transplantation Patient.

Am J Case Rep 2021 Jun 15;22:e931731. Epub 2021 Jun 15.

Medical Mycology Research Center, Chiba University, Chiba, Japan.

BACKGROUND Nocardia infections have rarely been reported in hematopoietic stem cell transplantation (HSCT) patients, who usually receive the prophylactic use of sulfamethoxazole/trimethoprim (ST) against Pneumocystis jiroveci. However, the ST prophylaxis, sensitive to Nocardia species, sometimes induces renal toxicities. Therefore, alternative prophylactic or therapeutic drugs are required for nocardiosis in HSCT patients. CASE REPORT A 34-year-old Japanese man with acute mixed phenotypic leukemia with t(9; 22) received allogenic peripheral blood HSCT from a haplo-identical sibling donor. He developed graft versus host disease (GVHD) with grade II, and was treated with prednisolone and cyclosporine A with concurrent ciprofloxacin, fluconazole, valacyclovir, and ST. However, the prophylactic ST was ceased because of its renal toxicity. He developed a pulmonary nodular lesion with elevated ß-D-glucan and Aspergillus galactomannan antigen. Repeated blood and sputum culture isolated no pathogens. Voriconazole treatment administered once improved these lesions and laboratory findings. One month later, he presented with right pleuritic chest pain and multiple ring-enhancing cavitation lesions along the ribs. A needle biopsy demonstrated Nocardia elegans, which is an extremely rare infection induced by Nocardia species, in the cavitation lesions, shown by 16S rRNA gene sequencing. He was started on doripenem and liposomal amphotericin B, and a subsequent treatment kept him free from Nocardia elegans infection, without any adverse effects, while continuing the cyclosporine A and prednisolone treatment for chronic GVHD. CONCLUSIONS Clarithromycin has fewer adverse effects than ST. This case suggests that clarithromycin is an appropriate alternative and prophylactic therapy for patients with nocardiosis and ST toxicities.
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http://dx.doi.org/10.12659/AJCR.931731DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8216568PMC
June 2021

meningitis in a diffuse large B-cell lymphoma patient with CD4-positive lymphocytopenia and persistent oligoclonal CD8-positive lymphocytes in the peripheral blood.

Int J Clin Exp Pathol 2018 1;11(1):455-461. Epub 2018 Jan 1.

Medical Mycology Research Center, Chiba University Chuo-Ku, Chiba, Japan.

Nocardiosis, sometimes presenting with multiple granulomatous lesions, is a rare opportunistic infection occurring in immunocompromised patients. However, its immunological features remain largely unaddressed. We investigated the immunological characteristics of human nocardiosis and examined the component cells of the granulomatous lesions. A 66-year-old man with diffuse large B-cell lymphoma presented with fever and multiple nodules in the lung during chemotherapy. The blood culture formed white colonies, but their characterization was difficult by routine microbiological laboratory methods. Matrix-assisted laser desorption ionization-time of flight mass spectrometry identified the colonies as . Meanwhile, the patient suddenly experienced an epileptic seizure without a brain abscess. His cerebrospinal fluid (CSF) showed neutrophilic pleocytosis (108/mm). The conventional agar culturing failed to isolate colonies, but culturing with brain-heart infusion agar generated colonies. These colonies were completely concordant with those from the blood, as confirmed by 16S rRNA gene sequencing. Therefore, the patient had developed meningitis through sepsis induced by . His CD4-positive T-lymphocyte counts were low, and oligoclonal CD8-positive αβ T-lymphocytes were present in the blood prior to the first and after three cycles of chemotherapy. He had bone marrow granulomatous lesions comprising lymphoma and CD8-positive αβ T-cells. Treatment with sulfamethoxazole/trimethoprim relieved all of his symptoms. The combined analysis by microbiological and molecular methods determined the cause of his epileptic seizure. His immunological characteristics, including low CD4-positive or CD8-positive αβ T-lymphocytes, may have contributed to the unusual clinical presentations by , which rarely involves the central nervous system.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6957946PMC
January 2018