MNNG-induced mutations in the adult gill and hepatopancreas and in embryos of rpsL transgenic zebrafish

Peripheral mononuclear leukocyte DNA damage, plasma prolidase activity, and oxidative status in patients with benign prostatic hyperplasia

OBJECTIVES

Prolidase plays a major role in collagen turnover, matrix remodeling, and cell growth. Benign prostatic hyperplasia (BPH) may be associated with an increased extracellular matrix deposition. Therefore, the present study was designed to investigate the plasma prolidase activity, oxidative status, and peripheral mononuclear leukocyte DNA damage in patients with BPH.

PATIENTS AND METHODS

Twenty-six male patients with BPH and 24 healthy male subjects were included in this study. Blood samples were collected from antecubital vein after an overnight fasting period, and the plasma was separated. Plasma prolidase activity, total antioxidant capacity (TAC), total oxidant status (TOS), and oxidative stress index (OSI) were determined. The peripheral lymphocyte oxidative DNA damage was determined using an alkaline single cell gel electrophoresis assay (comet assay).

RESULTS

The plasma prolidase activity, TOS levels, OSI values, and peripheral mononuclear leukocyte DNA damage were significantly higher (P < 0.001), while the TAC levels were significantly lower (P < 0.001) in patients with BPH than controls. In BPH patients, the prolidase activity was significantly associated with TAC levels (r = -0.366, P < 0.05), TOS levels (r = 0.573, P < 0.001), and OSI (r = 0.618, P < 0.001) and peripheral mononuclear leukocyte DNA damage (r = 0.461, P < 0.001).

CONCLUSIONS

Our results showed that BPH might be associated with an increased oxidative stress, and also an increased plasma prolidase activity. Increased prolidase activity might play an important role in the etiopathogenesis and/or progression of BPH.

Materials for zebrafish research outreach activities in National Institute for Environmental Studies, Japan

To promote application of the fruits of zebrafish research, we need to cultivate understanding of the use of zebrafish not only in the research community but also among the general public. On Open Days at our institute, the National Institute for Environmental Studies (NIES), our zebrafish group exhibits our research activity to the public. I explain here how we enable visitors to observe zebrafish embryogenesis under stereomicroscopes. Two kinds of materials handed out to participants are introduced and included: a zebrafish embryogenesis flip book and a mini guide to zebrafish. These materials serve as tools for our outreach activity and to promote further understanding of zebrafish research.

Zebrafish assays for drug toxicity screening

Zebrafish are vertebrate organisms that are of growing interest for preclinical drug discovery applications. Zebrafish embryos develop most of the major organ systems present in mammals, including the cardiovascular, nervous and digestive systems, in < 1 week. Additional characteristics that make them advantageous for compound screening are their small size, transparency and ability to absorb compounds through the water. Furthermore, gene function analysis with antisense technology is now routine procedure. Thus, it is relatively simple to assess whether compounds or gene knockdowns cause toxic effects in zebrafish. Assays are being developed to exploit the unique characteristics of zebrafish for pharmacological toxicology. This review discusses assays that may be used to assess in vivo toxicity and provides examples of compounds known to be toxic to humans that have been demonstrated to function similarly in zebrafish.

Isolation of the retinoblastoma cDNA from the marine flatfish dab (Limanda limanda) and evidence of mutational alterations in liver tumors

We have isolated a dab (Limanda limanda) homologue of the human retinoblastoma (Rb) tumor suppressor gene. The L. limanda partial Rb cDNA encodes a partial predicted protein of 753 amino acids. DNA sequence analysis with other vertebrate Rb sequences demonstrates that the L. limanda Rb cDNA is highly conserved in regions of functional importance. The sequence reported herein, combined with the high degree of conservation observed in critical domains, has also facilitated an investigation of the molecular etiology of environmentally induced liver tumor samples in a feral fish species. Mutational alterations were detected in liver adenoma samples, also in apparently "normal" regions of liver samples dissected from fish displaying adenoma, but not in normal liver samples from otherwise healthy feral fish. These results are the first reporting the appearance of Rb mutations in wild-caught fish and suggest that the molecular etiology of fish cancer appears to involve Rb-implicated tumorigenesis. The ecotoxicological relevance of the Rb mutations in feral fish liver tumors, in terms of future genome instability and possible development of a genotoxicity biomarker, is discussed.

Cytotoxic effects of the main active components from three Chinese herbal medicines on N-methyl-N-nitro-N-nitrosoguanidine transformed GES-1 cells

AIM: To investigate the cytotoxic effects of Panax Notogengsing Saponin (PNS), Astragalin Saponin (AS) and Baicalin (Ba), the main active components from 3 Chinese herbal medicines, on an immortalized human gastric epithelial cell line GES-1 and the N-methyl-N-nitro-N- nitrosoguanidine (MNNG) transformed GES-1 cells (MC cells).

METHODS: GES-1 cells were transformed by 2×10^-5 mol/L MNNG. The transformed cells were named as MC cells. MC cells were treated with the 3 medicines alone or in different combinations. Cell viability was detected by MTT assay and soft agar colony formation assay, while apoptosis/necrosis were determined by electron microscopy, fluoroscopy and flow cytometry with annexin V staining.

RESULTS: PNS, AS and Ba inhibited the growth of GES-1 and MC cells in a dose and time-dependent manner. The colony formation efficiency in soft agar of MC cells was also decreased after treated with PNS, AS, Ba alone or in combination (P<0.05 or P<0.01vs control group). The 3 medicines induced apoptosis and/or necrosis of MC cells time-dependently. These effects were greatly enhanced when two or three of these medicines were used together (P<0.05 or P<0.01 vs 3 medicines used alone). The most potent combination was PNS+AS+Ba, followed by PNS+AS, AS+Ba and PNS+Ba, in a decreasing order.

CONCLUSION: PNS, AS and Ba can inhibit cell growth and induce cell death on MC cells. The cell death is partially caused by cell apoptosis. These effects can be enhanced to different extent by different combinations of these drugs.