Inhibitory effects of NaF on mitochondrial energy generation in human platelets in vitro.

Background: fluoride is a beneficial ion that has been used in various fields, from industrial products to therapeutics. However, due to its narrow therapeutic index, fluoride sometimes acts as a toxic agent at relatively higher concentrations in the human body. Based on the interest in genetic stability, its cytotoxic effects have been investigated mainly in nucleated, adherent cells, such as fibroblasts. However, the sensitivity of blood cells, especially anucleate platelets, to fluoride is poorly understood. To fill this gap in the literature, we investigated the effects of relatively low levels of fluoride on platelet energy metabolism, function, and viability. Methods: Platelet-rich plasma (PRP) was prepared from 15 non-smoking healthy male adults (age: 28-63) and treated with NaF (0.5 or 1.0 mM) in microtubes for up to 3 days. Platelet function was evaluated based on aggregation and adhesion activities. Platelet energy metabolism was evaluated based on intracellular ATP levels, extracellular lactate levels, and respiration activities. The mitochondrial membrane potential (Em) and localization of reactive oxygen species (ROS) were visualized using cytochemical methods. Platelet viability was evaluated by cell counting and tetrazolium reduction. Result: NaF (1 mM) significantly reduced platelet viability and inhibited functions. Behind these phenomena, NaF substantially decreased mitochondrial Em and increased ROS production along with significant decreases in oxygen consumption and ATP levels. Simultaneously, NaF increased the lactate levels. Although not statistically significant, similar effects were observed at 0.5 mM NaF. Conclusion: At relatively low levels, NaF has the potential to attenuate platelet function probably primarily through the inhibition of mitochondrial energy generation. Cytotoxicity may be directly related to ROS production. These findings suggest that when used topically, for example, for caries prevention in the oral cavity, NaF could interfere with wound healing and tissue regeneration by endogenous and exogenously added platelets in the form of PRP.

Determination of starting materials, intermediates, and subsidiary colors in the color additive Food Red No. 106 (Sulforhodamine B) using high-performance liquid chromatography.

The main subsidiary color of structure in Food Red No. 106 (R106) was identified to be a desethyl derivative (R106-SubA). High-performance liquid chromatography (HPLC) was performed for the quantitative determination of benzaldehyde-2,4-disulfonic acid, N,N-diethyl-m-aminophenol, leuco acid, pyrone acid, R106-SubA, etc. in R106. An ammonium acetate solution (20mM) and acetonitrile:water (7:3) were used to stabilize the retention time of the HPLC analytes. The linearity of the calibration curves was in the range of 0.05-10µg/mL, with good correlation coefficients (R2>0.9983). The recoveries of impurities at levels 0.1%, 0.5% and 1% ranged from 94.2% to 106.6% with relative standard deviations of 0.1%-1.0%. While surveying commercial R106, the amounts obtained by area% determination were similar to those obtained by the calibration-curve determination. The area% determination by HPLC for the determinations of impurities in R106 is a simple and reliable method and can be applied in routine analysis.

Tumor angiogenesis and molecular target therapy in ovarian carcinomas.

Growth of solid tumors depends on angiogenesis, the process by which new blood vessels develop from the endothelium of a pre-existing vasculature. Tumors promote angiogenesis by secreting various angiogeneic factors, and newly formed blood vessels induce tumor cell proliferation and invasiveness. Ovarian carcinomas have a poor prognosis, often associated with multifocal intraperitoneal dissemination accompanied by intense neovascularization. The degree of angiogenesis of ovarian carcinomas may directly influence the clinical course of the disease. Although a growing body of evidence indicates that angiogenic intensity may play a prognostic role in gynecological malignancies including ovarian carcinomas, the related biological mechanisms remain to be further elucidated. In this review, we describe current knowledge pertaining to mechanisms and regulation of angiogenesis in ovarian carcinomas with special reference to our recent research results.

Glutathione S-transferase GSTM1, GSTT1 and p53 codon 72 polymorphisms in human tumor cells.

The genes of the glutathione S-transferase (GST) family encode enzymes that appear to be critical in cellular protection against the cytotoxic effects, whereas p53 is a tumor suppressor gene. Despite a large number of studies on germline polymorphisms of GSTM1, GSTT1 and p53 genes, there have been very few reports on genotyping of these genes in human malignant tumor cells. In this study, we investigated GSTM1, GSTT1 and p53 codon 72 polymorphisms in a variety of human tumor cell lines originating from different organs to clarify tissue-specific polymorphic frequency of these genes in human solid tumors. The GSTM1 and GSTT1 genetic polymorphisms were evaluated using multiplex PCR techniques and PCR-RFLP analysis was conducted to identify p53 codon 72 genotypes. Gene expression of GSTM1 or GSTT1 was detected by RT-PCR in the cells with respective present genotype for each. Polymorphisms of p53 codon 72 detected by PCR-RFLP were also confirmed using SSCP and sequence analyses. GSTM1 and GSTT1 genotypes were various in 104 cell lines examined. Null GSTM1 genotype was dominant in small cell lung, kidney and ovarian carcinoma cells, whereas null GSTT1 genotype was dominant in cervical and endometrial carcinoma cells. GSTM1 and GSTT1 genotypes in ovarian carcinoma cells were quite similar to those in small cell lung carcinoma cells. Polymorphic frequency of p53 codon 72 was also various among the cells, however, the Pro allele was found in only 1 of 6 kidney, 14 cervical and 4 endometrial carcinoma cell lines. There was a significant difference in GSTM1 and p53 genotypes between 34 small cell and 24 non small cell lung carcinoma cells (P < 0.01). Combined study on the distribution of GSTM1, GSTT1 and p53 genotypes revealed that null GSTM1 genotype was associated with the Arg allele of p53 codon 72 in 58 lung carcinoma cells and null GSTT1 genotype was associated with the Pro/Pro homozygote in 104 tumor cell lines examined. This is the first study examining GSTM1, GSTT1 and p53 codon 72 polymorphisms in a variety of human solid tumor cells and suggesting that polymorphic frequency of these genes may be tissue- and organ-specific. The molecular interaction between GST gene defects and p53 codon 72 genotype in the development of human malignant tumors should be further investigated.

Diagnostic and therapeutic laser conization for cervical intraepithelial neoplasia.

OBJECTIVE: The clinical efficacy of conservative treatment using Nd-YAG laser technique for cervical intraepithelial neoplasia (CIN) was evaluated in a large series of CIN patients based on the long-term follow-up results. METHODS: We have treated 2107 women preoperatively diagnosed as having CIN by Nd-YAG contact laser conization with vaporization of the base. Their postoperative histologic findings and clinical outcomes were evaluated. RESULTS: The cone specimen was reported as showing that 1956 (92.8%) of 2107 cases had no CIN or CIN 1-3 and 151 (7.2%) cases had invasive diseases. 1956 cases without invasive diseases were followed up for 16 to 252 months. Incomplete excision occurred in 230 (12.3%) of 1874 patients with CIN lesion in the cone specimen, but failure rate (persistence or recurrence) was only 1.2%. 192 (83.5%) of 230 postoperative CIN patients with positive surgical margins showed no abnormal cytology or colposcopy during follow-up period. Preoperative underdiagnosis of biopsy results compared with cytologic or colposcopic findings elevated the risk for incomplete excision and failure rate. CONCLUSION: The combination of laser excision and vaporization of the base was useful to detect unexpected invasive disease and revealed excellent therapeutic effects for CIN. Preoperative cytologic or colposcopic findings should be taken into account for the conservative treatment of CIN.

Germline polymorphism of p53 codon 72 in gynecological cancer.

OBJECTIVE: To investigate the biological significance of single nucleotide polymorphism at codon 72 of the p53 gene in the development of gynecological cancer. METHODS: p53 codon 72 polymorphism was examined in a total of 354 blood samples from 95 normal, 83 cervical, 108 endometrial and 68 ovarian cancer cases using polymerase chain reaction and restriction fragment length polymorphism techniques. RESULTS: When p53 codon 72 genotype was classified into two subgroups of Arg/Arg and Arg/Pro + Pro/Pro, the Arg/Arg genotype was associated with an increased risk for the development of endometrial cancer (OR = 1.86, 95% CI = 1.06 to 3.26) compared with the Arg/Pro + Pro/Pro genotype (P = 0.0301). The Arg allele also increased the risk of endometrial cancer (OR = 1.42, 95% CI = 0.93 to 1.52) compared with the Pro allele, but no statistical difference was found (P = 0.1031). There was no significant difference in the genotype or allele prevalence between control subjects and cervical or ovarian cancer patients. CONCLUSION: Homozygous Arg at codon 72 of the p53 gene may be a risk factor for developing endometrial cancer in a Japanese population.