Virantmycin, a novel chlorine-containing antiviral antibiotic, has been isolated from Streptomyces nitrosporeus No. AM-2722. The active substance in culture broth is isolated as colorless needles by solvent extraction followed by high performance liquid chromatography on silicic acid. The molecular formula is C18H26NO3C1 (molecular weight 351) from the elemental analysis and mass spectrum. The antibiotic possesses antifungal activity and potent inhibitory activity against various RNA and DNA viruses.In the course of our screening program for IFN (interferon) inducers and antiviral substances from Streptomyces, we found that Streptomyces sp. No. AM-2722, isolated from the putrefied tissue portion of a pumpkin, produces a novel antibiotic possessing a potent inhibitory activity against both RNA and DNA viruses.') The antibiotic also shows weak antifungal activity. The antibiotic, named virantmycin, is a novel antiviral antibiotic containing chlorine. The structure of virantmycin has been reported elsewhere.') In this paper, we describe the taxonomy of the producing strain, and the production, isolation and physicochemical and biological properties of virantmycin.
Taxonomic StudiesStrain AM-2722 was isolated from a pumpkin spoiled by microorganisms.The strain was cultivated at 27°C for 14 days on various media such as yeast extract-malt extract agar, inorganic saltsstarch agar, glucose -asparagine agar and tyrosine agar. Its morphological characteristics were ex-
In contrast to malignant lymphomas or skin cancer, smooth muscle tumors including leiomyosarcoma are rarely associated with transplant recipients. We herein present a 33-year-old woman with end-stage renal disease who received a transplant at 27 years of age. Four years after the transplantation, at age 31, she underwent a mastectomy because of primary right breast cancer, which was found to be a 5-mm-sized mucinous carcinoma with no regional lymph node metastasis. Six years after the transplantation, a liver tumor was unexpectedly discovered. An explorative laparotomy revealed a well-encapsulated tumor occupying the posterior portion of the right lobe of the liver. The patient underwent a posterior segmentectomy. Histologically, the tumor possessed intermingling fascicles of spindle cells with eosinophilic cytoplasm and elongated nuclei. Based on an immunohistochemical examination, the tumor cells were positive for the muscle-associated antibody. In addition, RNA probes for Epstein-Barr virus were negative based on in situ hybridization. The histologic, immunohistochemical findings were considered to be diagnostic for leiomyosarcoma, which is a low-grade malignancy. Two years after surgery, the patient is doing well with no recurrence of liver tumors or breast cancer.
The present study sought to identify the therapeutic efficacy of adjuvant external beam radiotherapy (EBRT) for carcinomas of the extrahepatic bile duct (EHBD) and gallbladder. Twenty-one patients with pathologically verified EHBD carcinoma and 18 patients with gallbladder carcinoma were analyzed retrospectively by Cox regression analysis for predictors of survival. The overall 5-year survival rates after resection were 33% for EHBD carcinoma and 56% for gallbladder carcinoma. The overall 5-year survival rate for EHBD carcinoma was 60% in 8 patients without microscopic residual disease (R0), 15% in 9 patients with microscopic residual tumor (R1), and 0% in 4 patients with macroscopic residual tumor (R2). The overall 5-year survival rate of gallbladder carcinoma patients was also decreased with R status equal to 73%, 40%, and 0% for R0, R1 and R2, respectively. Adjuvant radiotherapy significantly improved the 5-year survival rate in 7 patients with R1 disease of EHBD carcinoma (P = .035), compared with survival in 2 patients who underwent resection alone. However, no significant difference was noted in the 5-year survival rate between the resection plus EBRT group and the resection alone group for gallbladder carcinoma. Multivariate analysis revealed that histopathologic grade (G) was an independent predictor of survival for EHBD carcinoma and that direct invasion of liver parenchyma was a predictor of survival for gallbladder carcinoma. This study suggests that curative resection provides the best survival for patients with EHBD and gallbladder carcinoma, and that radiotherapy may play a beneficial role in controlling local-regional residual EHBD carcinoma tumors. However, new strategies for adjuvant therapy are needed to improve survival in patients with gallbladder carcinoma.
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