Anticarcinogenic activity of blue fluorescent hexagonal boron nitride quantum dots: as an effective enhancer for DNA cleavage activity of anticancer drug doxorubicin.

Blue fluorescent hexagonal boron nitride quantum dots (h-BNQDs) of ∼10 nm size as an effective enhancer for DNA cleavage activity of anticancer drug doxorubicin (DOX) were synthesized using simple one-step hydrothermal disintegration of exfoliated hexagonal boron nitride at very low temperature âˆ¼ 120 °C. Boron nitride quantum dots (BNQDs) at a concentration of 25 µg/ml enhanced DNA cleavage activity of DOX up to 70% as checked by converting supercoiled fragment into nicked circular PBR322 DNA. The interaction of BNQDs with DOX is proportional to the concentration of BNQDs, with binding constant K b ∼0.07338 µg/ml. In addition, ab initio theoretical results indicate that DOX is absorbed on BNQDs at the N-terminated edge with binding energy -1.075 eV and prevented the normal replication mechanisms in DNA. BNQDs have been shown to kill the breast cancer cell MCF-7 extensively as compared with the normal human keratinocyte cell HaCaT. The cytotoxicity of BNQDs may be correlated with reduced reactive oxygen species level and increased apoptosis in MCF-7 cells, which may be liable to enhance the anticancerous activity of DOX. The results provide a base to develop BNQD-DOX as a more effective anticancer drug.

Semi-quantitative HPV viral load in patients with ASC-US cytology: viral load correlates strongly with the presence of CIN but only weakly with its severity.

OBJECTIVES: This study was performed to evaluate the prognostic significance of human papillomavirus (HPV) viral load, expressed in relative light units (RLUs), in patients with atypical squamous cells of undetermined significance (ASC-US) cytology. METHODS: A total of 349 ASC-US cases with HPV infection, detected using Hybrid Capture 2, were diagnosed histologically. A colposcopically directed punch biopsy was performed on acetowhite areas. Endocervical curettage biopsy and random cervical punch biopsy in four quadrants were performed in unsatisfactory colposcopy cases. In negative colposcopy cases, random cervical punch biopsy in four quadrants was performed. RESULTS: Case with no cervical intraepithelial neoplasia (CIN), CIN1 and CIN2+ (CIN2/CIN3) accounted for 162, 135 and 52 cases, respectively. The mean age showed no difference among the three groups (P = 0.510). There was a significant correlation between RLU values and the presence of CIN (P < 0.001), but less so with its severity: the median RLU values for negative, CIN1 and CIN2+ cases were 42.68, 146.45 and 156.43, respectively, with widely overlapping confidence intervals. The cut-off values of RLU to detect CIN1+ and CIN2+ were 6.73 and 45.64, respectively. CONCLUSIONS: The HPV viral load in ASC-US cases showed a significant correlation with the presence of CIN and less so with its severity, and showed large overlap of viral loads between grades of CIN. In ASC-US cases, RLU was not an accurate predictor of immediate high-grade CIN.

Synthesis and cytotoxic effects of deoxy-tomentellin.

Cannabigerol (1, CBG), methyl 4-[(2E)-3,7-dimethyl-2,6-octadienyl)oxy]-3-methoxybenzoate (2, DTM), 5-fluorouracil (3, FU) as a reference, and cannabidiol (4, CBD) were tested for their growth inhibitory effects against KB(ATCC NO, OCL 17) cell lines using two different assays, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazoliumbromide (MTT) assay and the sulforhod-amine B protein (SRB) assay. These compounds showed inhibitory activity in vitro in the micromolar range against KB cell lines. In general, the antitumor activities of these compounds (1, 2, 3 and 4) were dose-dependent over the micromolar concentration range of 1 to 100 M. The comparison of IC50 values of these compounds in tumor cell lines showed that their susceptibility to these compounds decreases in the following order: DTM > CBD > 5-FU > CBG by MTT assay and DTM = CBD > 5-FU > CBG by SRB assay. CBG 1, DTM 2, 5-FU 3, and CBD 4 were tested for their cytotoxic effects on NIH 3T3 fibroblasts using two different assays, the MTT assay and SRB assay. These compounds exhibited potent cytotoxic activities in vitro in the micromolar range against NIH 3T3 fibroblasts. In general, the cytotoxic activities of these compounds (1, 2, 3 and 4) were dose-dependent over the micromolar concentration range of 1 to 100 M. The comparison of CD50 values of these compounds in NIH 3T3 fibroblasts shows that their susceptibility to these compounds in decreases the following order(:) CBD > 5-FU > DTM > CBG by MTT assay, CBD > 5-FU > CBG > DTM by SRB assay. These results suggest that DTM 2 has the most growth-inhibitory activity against KB cell lines.

High-level expression of recombinant human soluble thrombomodulin in serum-free medium by CHO-K1 cells.

Cultivation of gene-engineered Chinese hamster ovary (CHO-K1) cells that produce recombinant human soluble thrombomodulin (rsTM) was investigated to optimize conditions for high-level expression of the protein in a serum-free medium. For economic protein production, oxygenation of cultures with pure O2 permitted sufficient cell growth for high rsTM production with only 1 g/l of microcarriers and a low foetal bovine serum concentration. A longer growth phase (over 5 days) with serum was important to establish sufficient growth of this cell line on the microcarriers for subsequent serum-free culture, and to support a long-term production phase (about 2 months). In the production phase, a high glucose concentration (6.15 g/l) in the serum-free medium was very effective for prolonging the harvest cycle interval. Under these conditions, up to 100 mg/l rsTM was expressed in the conditioned medium. The rates of glucose consumption (G) and lactate production (L) were measured periodically and their ratio (L/G ratio) correlated with rsTM productivity. When the average L/G ratio was lower, reflecting a lower lactate production rate due to appropriate oxygenation of the culture, the specific rsTM production rate increased. Thus it may be possible to estimate protein productivity from L/G ratios calculated from the glucose and lactate measurements.