[Effects of mesalazine on liver carcinogenesis in medium-term bioassay using rats]

A two stage carcinogenesis promotion test using phenobarbital (PB) as a positive control was performed on mesalazine in rats (F344,male). Pathological and immunohistological examinations were performed to examine the cell damage and proliferation in the liver and kidneys. As the initiation treatment, groups 1,2,3 and 5 were administered 300 mg/kg diethylnitrosamine (DEN)dissolved in 0.9% physiological saline, and group 4 was administered 5 ml/kg 0.9% physiological saline once intraperitoneally. Then group 1 was orally administered a water solution (5 ml/kg) containing 0.5% CMC-Na, and groups 2,3 and 4 similar water solution but containing 150, 300 and 300 mg/kg mesalazine, respectively. Group 5 was administered 0.05% PB mixed in feed from weeks 2 to 8. Partial (2/3) hepatectomy was performed in all 5 groups at week 3 after DEN administration. NO clear differences between the groups were observed in general conditions, body weight or amount of food consumption. The number or area-size of hepatic GST-P positive altered cell foci revealed no significant differences between groups 1,2 and 3, but a significant increase in number and area-size was observed in group 5. No GST-P positive cell foci were detected in group 4. The number of altered cell foci (H.E. staining) in the DENgroups administered mesalazine was the same as that in group 1. Thus, mesalazine did not promote hepatocarcinogenesis in the present experimental system. Statistically insignificant appearances of basophilic and acidophilic changes were observed in the renal tubular epithelium and mineral deposits in the renal papillary region and cortical margin region. The PCNA labeling rate was significantly lower in group 4, corresponding with the histological finding showing no proliferation of the renal tubular epithelium. Judging from the above test results, mesalazine was likely to show neither a promotion effect on the initiation induced by DEN nor cell proliferative activity on the kidneys by administration for this experimental period.

Inhibition of tumor promoter activity toward mouse fibroblasts and their in vitro transformation by tissue inhibitor of metalloproteinases-1 (TIMP-1)

Tissue inhibitor of metalloproteinases-1 (TIMP-1), a natural inhibitor of matrix metalloproteinases (MMPs), is known to inhibit invasion and metastasis of tumor cells. In the present study we examined anti-tumor promoter activity of TIMP-1 and its effect on in vitro cell transformation using BALB/3T3 cells in low serum culture medium. In the dye transfer assay the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) continuously blocked gap-junctional intercellular communication (GJIC) of BALB/3T3 cells in confluent phase. TIMP-1 did not prevent transient inhibition of GJIC induced by TPA, but it quickly restored the reduced GJIC level to the control level. The recovery of GJIC was dependent on the concentration of TIMP-1 from 1 to 1000 ng/ml. In an in vitro two-stage transformation assay in which BALB/3T3 cells were treated with 0.5 microg/ml N-metyl-N'-nitro-N-nitrosoguanidine as initiator and 100 ng/ml TPA as promoter, TIMP-1 at concentrations > 10 ng/ml inhibited the focus formation of transformed cells by approximately 60%. TIMP-2 and a synthetic MMP inhibitor showed a similar inhibitory activity on in vitro cell transformation. Furthermore, zymographyic analysis showed that TPA treatment of BALB/3T3 cells induced secretion of gelatinase B and stromelysin-1 into the culture medium. These results indicate that TIMP-1 and TIMP-2 have inhibitory activity on in vitro transformation of cells. It seems likely that TPA-inducible MMPs are involved in carcinogenesis and TIMPs have a protective role against carcinogenesis in vivo.

Inhibition of amyloid beta protein aggregation and neurotoxicity by rifampicin. Its possible function as a hydroxyl radical scavenger

Aggregation of physiologically produced soluble amyloid beta protein (Abeta) to insoluble, neurotoxic fibrils is a crucial step in the pathogenesis of Alzheimer's disease. Aggregation studies with synthetic Abeta1-40 peptide by the thioflavin T fluorescence assay and electron microscopy and cytotoxicity assays using rat pheochromocytoma PC12 cells showed that an antibiotic, rifampicin, and its derivatives, which possess a naphthohydroquinone or naphthoquinone structure, inhibited Abeta1-40 aggregation and neurotoxicity in a concentration-dependent manner. Hydroquinone, p-benzoquinone, and 1,4dihydroxynaphthalene, which represent partial structures of the aromatic chromophore of rifampicin derivatives, also inhibited A beta1 40 aggregation and neurotoxicity at comparable molar concentrations to rifampicin. Electron spin resonance spectrometric analysis revealed that the inhibitory activities of those agents correlated with their radical-scavenging ability on hydroxyl free radical, which was shown to be generated in cell-free incubation of Abeta1-40 peptide. These results suggest that at least one mechanism of rifampicin-mediated inhibition of A beta aggregation and neurotoxicity involves scavenging of free radicals and that rifampicin and/or appropriate hydroxyl radical scavengers may have therapeutic potential for Alzheimer's disease.

Release of superoxide radicals by mouse macrophages stimulated by oxidative modification of glycated low density lipoproteins

Diabetic patients have high levels of glycated LDL. Although glycated LDLs are implicated in the development of atherosclerosis in such patients, convincing data are lacking. We observed release of superoxide radicals (O2-) from mouse resident peritoneal macrophages stimulated by an oxidized/glycated LDL by using a highly sensitive and specific chemiluminescence method. Oxidized/glycated LDL was achieved by an addition of low concentration of Fe3+ to glycated LDL. Macrophages took up an appreciable amount of the glycated LDL oxidized by iron, leading to the development of foam cells, while they did not take up untreated glycated LDL or the native LDL. These observations clearly indicate that the oxidized/glycated LDL reacts well with macrophages. Since an oxidation of glycated LDL may occur in vivo, the oxidized/glycated LDL might play an important role in atherogenesis.

[Leukoencephalopathy in a patient being treated for small cell lung cancer]

A 62-year-old man was given a diagnosis of small cell lung cancer, and received 6 courses of combination chemotherapy (PE therapy) composed of cisplatin (80 mg/m2, day 1) and etoposide (100 mg/m2, days 1, 2, 3). Multiple brain metastases were found, and whole brain irradiation (44 Gy) was given. Eleven months after radiotherapy, he suffered from dizziness and abnormal gait. Enhanced CT of the head showed slight enlargement of the lateral ventricles and markedly low density of the white matter, but no evidence of intracranial tumor involvement. A magnetic resonance scan (axial T2-weighted) showed symmetric extensive hyperintensity in the white matter. Treatment-related leukoencephalopathy caused by the PE therapy and whole brain irradiation was diagnosed. He was alive 8 months after the appearance of neurological symptoms, without recurrence of lung cancer. A search of the literature revealed no previous report of leukoencephalopathy related to PE therapy.

Solitary plasmacytoma of the mandible. Case report and review of the literature

A case of solitary plasmacytoma of the mandible is presented. Review of the literature disclosed the following characteristics regarding the clinical course and prognosis. The patients ages ranged from 34 to 76 years, with a mean of 53 years; there was a marked preponderance of males. The site of predilection was the posterior portion of the mandible. The common symptom was a non-painful swelling of the mandible of long duration, and radiological features were non-specific. Monoclonal immunoglobulin was initially detected in 42% of the evaluated patients. The majority of patients were treated with radiation therapy with a mean dose of 48Gy with or without surgery. The period of follow-up ranged from 4 months to 12 years, and 17% of the patients progressed to multiple myeloma within 1 year.

Abnormal sclerocytes in nanophthalmos

Scleral tissue from a nanophthalmic patient was examined morphologically and by a tissue culture method. Collagen in the unusually thickened scleral tissue was arranged in irregularly interlacing bundles. Results of tissue culture studies showed sclerocytes that seemed to secrete many granules that stained positively with Alcian blue and periodic acid-Schiff (PAS). No granules were seen in cells of scleral tissue cultured from two control eyes. These findings may be the result of the modified glycosaminoglycan metabolism, which in turn contributes to the abnormal packing of collagen bundles and thickening of sclera in nanophthalmos.

Pulmonary aspergillosis due to Aspergillus terreus combined with staphylococcal pneumonia and hepatic candidiasis

A female patient with systemic lupus erythematosus (SLE) developed pulmonary aspergillosis with staphylococcal pneumonia and hepatic candidiasis. Aspergillus terreus, which is a rare causative organism of pulmonary aspergillosis, was identified from a pulmonary lesion by culture. The aleurioconidium production, a characteristic of the genus Aspergillus sect. terrei, was demonstrated on short and irregular hyphal features in tissue sections. This report is the first of a combined case of pulmonary aspergillosis due to A. terreus with infections caused by other microorganisms.

Necessity of transferrin for RNA synthesis in chick myotubes

Chick transferrin (Tf) is essential not only for growth and differentiation but also for the maintenance of chick myotubes in culture. Its removal from the culture medium gives rise to degeneration of the myotubes. The analysis of this process revealed that the removal resulted in decrease in total and messenger RNA content in the myotubes; this was mainly due to a decrease in RNA synthesis. Activity of in vitro RNA synthesis in isolated nuclei from myotubes cultured without Tf was lower than the activity in nuclei from myotubes cultured with Tf and increased with the addition of FeCl3. Although RNA degradation in myotubes was also enhanced following Tf removal, the degree was small. The synthesis of most proteins was reduced. In contrast to this, a few new proteins of unknown nature were synthesised in myotubes cultured in Tf-free medium. The role of Fe ion carried into the cells by Tf in promoting myogenic cell growth and differentiation and in preventing the myotubes from degeneration can be explained, at least in part, on the basis of its effect on RNA synthesis. Since we have found that Fe is required for activation of RNA polymerase purified from embryonic muscles (Shoji and Ozawa, 1985b), these effects may be ascribed to this activating effect.

The relationship of Phialophora verrucosa to Phialophora americana

Phialophora verrucosa and P. americana, two dematiaceous hyphomycetes, are known to cause chromoblastomycosis. Even though most medical mycologists consider P. americana as synonymous with P. verrucosa, others maintain them as two distinct species on the basis that the phialides of P. americana have deeper collarettes than those of P. verrucosa. Thirty-two isolates, identified either as P. americana or P. verrucosa, were studied for their morphologic, physiologic, and antigenic characteristics to evaluate their taxonomic status. Collarette morphology was found to be a variable character in 12 of the 32 isolates. Those 12 produced phialides with both shallow and deep collarettes. All of the isolates hydrolysed urea within 7 days at 25 degrees C, and failed to liquefy gelatin after 3 weeks at 25 degrees C. None of the isolates decomposed casein, xanthine, or hypoxanthine at the end of 3 weeks at 25 degrees C. All decomposed tyrosine. They grew at 25 degrees C and 37 degrees C, but failed to grow at 40 degrees C. The antigenic relationship between the two species was studied by the exoantigen procedure. The 32 isolates showed close antigenic relatedness. Adsorptions of antisera with homologous and heterologous antigens rendered the antisera free of precipitin bands when studied by the microimmunodiffusion test. The depth of phialide collarettes produced by the two species, being found to be variable character, and the identical nature of the two species with respect to their physiologic and antigenic characteristics, led us to conclude that P. americana should be considered as a synonym of P. verrucosa.

Orchid allergy

A female office worker acquired contact allergy by handling Cymbidium cultivars for several years. The sensitizing properties of this ornamental orchid were demonstrated by experimental sensitization of guinea pigs. Chemical analysis of the ether extracts disclosed the presence of two quinones. The structure of the main quinone was elucidated as 2,6-dimethoxy-1,4-benzoquinone by x-ray crystallographic analysis. In the patient and in the sensitized animals, only this quinone elicited strong reactions, while tests with the second constituent were negative or gave only weak responses. Although 2,6-dimethoxy-1,4-benzoquinone is only a moderately strong sensitizer, its role as a contact allergen is emphasized, as it has been found in more than 50 different plant and wood species.

Conduction of nonconjugative plasmids by F' lac is not necessarily associated with transposition of the gamma delta sequence

A nonconjugative kanamycin-resistant (Kmr) recombinant plasmid, pNR5311, transferred at a low frequency from an Hfr or F' lac Escherichia coli donor to an F- lac- recipient. Among the transconjugants, two types of Kmr plasmids were found: one was indistinguishable from pNR5311 (type A), and the other was a recombinant between pNR5311 and the gamma delta sequence (type B). When the F' lac strain was used as a donor, 5% of lactose-fermenting (Lac+) and 75% of lactose-nonfermenting (Lac-) transconjugants had type A plasmids. A kinetic study revealed that type A plasmids were transferred more readily in short mating periods than were type B plasmids. Involvement of Tn903, which is present in pNR5311, in transfer of type A plasmids was unlikely since there was no discernible change in the F' lac molecule coexisting with the type A plasmid in the transconjugant cells. The non-gamma delta-associated conduction of pNR5311 by F' lac did not require the recA+ function of the donor. Conduction of pBR322 by F' lac was also carried out, and two types of plasmids with and without gamma delta were found, as with pNR5311. These findings suggest that the transfer of nonconjugative plasmids is conducted by a novel pathway which is not associated with translocation of transposable elements into either plasmid.