CT and MRI characteristics for differentiating mediastinal Müllerian cysts from bronchogenic cysts.

AIM: To evaluate how computed tomography (CT) and magnetic resonance imaging (MRI) characteristics can be used to differentiate immunohistochemically confirmed mediastinal Müllerian cysts (MMCs) from bronchogenic cysts (BCs). MATERIALS AND METHODS: Sixteen patients with histopathologically and immunohistochemically confirmed mediastinal cysts (four with MMCs and 12 with BCs) were included in this study. CT and MRI images were reviewed retrospectively and the location, size, CT attenuation, and MRI signal intensity of the two pathologies were compared. RESULTS: On review of CT images, cysts could be located to the anterior mediastinum in four BCs, middle mediastinum in three MMCs and seven BCs, and posterior mediastinum in one MMC and one BC. Contact with a vertebral body was observed in 4/4 MMCs (100%) and 6/12 BCs (50%). The ratios of minimum-to-maximum diameter (0.57±0.09 versus 0.74±0.11, p<0.01), CT attenuation (7.8±6 versus 44.3±12 HU, p<0.01), and cyst-to-spinal cord signal intensity ratios (SIRs) on T1-weighted images (0.56±0.2 versus 1.31±0.4, p<0.01) were significantly lower for MMCs than BCs. No significant differences in maximum diameter, minimum diameter, and SIRs on T2-weighted images were found between MMCs and BCs. CONCLUSION: In characterising mediastinal cysts in a middle-aged female patient, contact with a vertebral body, flattened configuration, hypodensity on CT, and hypointensity compared to spinal cord on T1-weighted images are features that are specific to MMCs.

Pancreatic MRI associated with pancreatic fibrosis and postoperative fistula: comparison between pancreatic cancer and non-pancreatic cancer tissue.

AIM: To evaluate the potential value of magnetic resonance imaging (MRI) for predicting postoperative pancreatic fistula (POPF) in patients with pancreatic cancer (PC) and non-pancreatic cancer (non-PC). MATERIAL AND METHODS: This retrospective study was approved by the institutional review board and written informed consent was waived. Forty patients underwent pancreatoduodenectomy due to PC (n=31) and non-PC (n=9). The pancreas-to-muscle signal intensity ratio (SIR) on three-dimensional (3D)- fast field echo (FFE) T1-, in- and opposed-phase T1-, and T2-weighted images, as well as the apparent diffusion coefficient (ADC) value of the pancreas were measured. The frequency of POPF and MRI measurements were compared between patients with PC and non-PC. The MRI measurements were also compared with the grade of pancreatic fibrosis on pathological findings, fat deposition, and interstitial oedema. RESULTS: The frequency of POPF was significantly higher in patients with non-PC than in those with PC (p=0.0067), with an odds ratio of 10.4. The SIR on 3D-FFE T1-weighted images was significantly higher in patients with non-PC (p=0.0001) and those with POPF (p=0.017) than in those with PC and those without POPF, respectively. Multiple regression analysis demonstrated that the SIR on 3D-FFE T1-weighted image was independently associated with the grade of pancreatic fibrosis (p<0.0001). CONCLUSION: The frequency of POPF was significantly higher in patients with non-PC than in those with PC was inversely related to the grade of pancreatic fibrosis. The SIR on 3D-FFE T1-weighted image might be a potential imaging biomarker for predicting POPF.

Chemoprevention of 2-amino-1-methyl-6-phenylimidazo [4,5-b]pyridine-induced mammary carcinogenesis in rats.

Modifying effects of dietary exposure of diallyl disulfide (DAD), aspirin, DL-alpha-difluoromethylomithine (DFMO), beta-naphthoflavone (beta-NF), alpha-naphthoflavone (alpha-NF), indole-3-carbinol (I3C) and protocatechuic acid (PCA) on 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP)-induced mammary carcinogenesis were examined in two experiments with female rats. For both experiments, PhIP in corn oil at a concentration of 85 mg/kg was given to animals via an intragastric tube for eight doses for an initial 4 weeks, and test chemicals were given in the diet (Experiment 1: DAD, 200 ppm; aspirin, 400 ppm; DFMO, 400 ppm; beta-NF, 1000 ppm; Experiment 2: alpha-NF, 1000 ppm; I3C, 1000 ppm; PCA, 2000 ppm) for an initial 4 weeks. The experiments were terminated after 25 weeks. In Experiment 1, exposure of beta-NF decreased the incidence and multiplicity of total mammary tumors (fibroadenoma, intraductal carcinoma and invasive ductal carcinoma) (P < 0.001 and P < 0.0001), and lowered the incidence of ductal carcinoma (P < 0.0001). DAD lowered the incidence of ductal carcinoma and decreased the multiplicity of the total tumors (P < 0.01 and P < 0.005). Furthermore, aspirin decreased the total tumors (P < 0.05). In Experiment 2, alpha-NF decreased the multiplicity of ductal carcinoma (P < 0.05). These results suggest that alpha-NF, beta-NF, DAD or aspirin could be chemopreventing agents for mammary neoplasia.

The telomerase activities in several organs and strains of rats with ageing.

Telomerase activity is known to be implicated both in cell immortalization and carcinogenesis. Telomerase activity has not been detected in most human somatic tissues. However, we previously confirmed that the activity is present both in methylazoxymethanol acetate-induced rat colonic adenocarcinoma and non-treated colonic mucosa, presumably indicating the tissue-specific activity of the enzyme in rats. To determine the standard activity of rat telomerase in various organs in relation to differences in sex, age and strain, we examined the activity by using the telomeric repeat amplification protocol (TRAP) assay. The testis, liver, and colon mucosa showed the activity. The brain had very low or negative activity in 5-week-old male rats of the F344, SD, Wistar, Donryu or ACI strains. Age (5-week-old and 9-month-old) or sex difference for the activity was not apparent in rats of these strains. In general, telomerase activity in the fetal brain, liver and kidney was stronger than in the adult organ. The telomerase activity of each organ was different from that of human. This difference may indicate that the rat has a specific mechanism for maintaining the telomeric repeats of the chromosome even in somatic tissues. The basic information resulting from this study may be useful for the study of the role of telomerase in tumorigenesis in animal experiment models.

Inhibitory effects of diallyl disulfide or aspirin on 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine-induced mammary carcinogenesis in rats.

Modifying effects of diallyl disulfide (DAD), aspirin or DL-alpha-difluoromethylornithine (DFMO) on 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP)-induced mammary carcinogenesis in SD rats were investigated. A total of 166 female rats, 6 weeks old, were divided into 8 groups. They were fed a high fat diet throughout the experiment. Starting at 7 weeks of age, groups 1-4 were given PhIP (85 mg/kg body weight in corn oil) by gavage 8 times in 10 days, and groups 5-8 were given corn oil alone. For the beginning 4 weeks, groups 2 and 5 were given DAD at 200 ppm in diet. Similarly groups 3 and 6, and groups 4 and 7 were given aspirin (400 ppm) and DFMO (400 ppm), respectively. Mammary carcinomas were only recognized in groups 1-4 at the termination (25 weeks after the start of experiment). Multiplicity (mean number/rat) of neoplasms in group 2 (PhIP+DAD, 0.90/rat) and group 3 (PhIP+aspirin, 1.37/rat) was significantly smaller than that in group 1 (PhIP alone, 2.45/ rat) (P < 0.005 and P < 0.05, respectively). These results indicate that dietary intake of DAD or aspirin during the time corresponding to initiation phase has chemopreventive potential on PhIP-induced mammary carcinogenesis in rats.

[Futraful and UFT, their metabolic characteristics].

Investigations were made in human on the metabolism of Futraful (FT) and UFT (combination of uracil and FT), both of which are anticancer agents of pyrimidine metabolism antagonist. As a result, it was demonstrated that from the metabolic view point, those drugs essentially have a tumor-selective toxicity. Next, the mechanism of the superior clinical anticancer effect of UFT, compared to FT, was investigated enzymatically, showing the inhibitory effect of uracil on the degradation of 5-fluorouracil generated from FT in the organs and tumor tissues. Discussions were also made for the further development of fluoropyrimidines.